Patent Publication Number: US-2021191661-A1

Title: Electronic control unit, vehicle electronic control system, rewrite execution method, rewrite execution program, and data structure of specification data

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of PCT/JP2019/031177 filed on Aug. 7, 2019, which designated the U.S. and claims the benefit of priority from Japanese Patent Application No. 2018-151429 filed on Aug. 10, 2018 and Japanese Patent Application No. 2019-129970 filed on Jul. 12, 2019. The entire disclosures of all of the above applications are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to an electronic control unit, a vehicle electronic control system, a rewrite execution method, a rewrite execution program, and a data structure of specification data. 
     BACKGROUND ART 
     There is a proposed technique in which a vehicle master device as a relay device is provided on a vehicle side, and the vehicle master device distributes update data received wirelessly from a center device to a rewrite target electronic control unit (ECU) and instructs the rewrite target ECU for write of the update data such that a program of the rewrite target ECU is rewritten through Over The Air (OTA). 
     SUMMARY OF THE INVENTION 
     The present disclosure provides an electronic control unit, a vehicle electronic control system, a rewrite execution method, a rewrite execution program, and a data structure of specification data. 
     An example of an electronic control unit comprises a non-volatile memory having a first data storage bank and a second data storage bank. At least one of an application program or parameter data is stored in each of the first data storage bank and the second storage bank. The electronic control unit operates at least one of the application program or the parameter data stored in the first data storage bank serving as an active bank and rewrites the second data storage bank serving as an inactive bank by writing, to the second data storage bank, update data acquired from an external device. The electronic control unit switches the active bank from the first data storage bank to the second data storage bank. The electronic control unit rewrites the second data storage bank during a vehicle being travelable or parked, and switches the active bank from the first data storage bank to the second data storage bank during the vehicle being parked. 
     An example of a vehicle electronic control system comprises: a vehicle master device that distributes update data to an electronic control unit; and an electronic control unit that includes a non-volatile memory having a first data storage bank and a second data storage bank each storing at least one of an application program or parameter data and that writes the update data received from the vehicle master device to the non-volatile memory. When it is determined a first predetermined condition regarding a rewrite target electronic control unit is satisfied, the vehicle master device instructs the rewrite target electronic control unit for installation during the vehicle being travelable. When it is determined a second predetermined condition regarding a rewrite target electronic control unit is satisfied, the vehicle master device instructs the rewrite target electronic control unit for installation during the vehicle being parked. After completion of the installation, he vehicle master device instructs the rewrite target electronic control unit for activation during parked. 
     An example of a rewrite execution method is a method in an electronic control unit that includes a non-volatile memory having a first data storage bank and a second data storage bank, wherein at least one of an application program or parameter data is stored in each of the first data storage bank and the second storage bank. The execution control method comprises: an installation execution procedure of, during a vehicle being travelable or parked, operating at least one of the application program or the parameter data stored in the first data storage bank serving as an active bank and rewriting the second data storage bank serving as an inactive bank by writing update data acquired from an external device to the second data storage bank; and an activation execution procedure of switching the active bank from the first data storage bank to the second data storage bank during the vehicle being parked. 
     An example of an execution control program that causes an electronic control unit including a non-volatile memory having a first data storage bank and a second data storage bank each storing at least one of an application program or parameter data to perform: an installation execution procedure of, during a vehicle being travelable or parked, operating the application program or the parameter data stored in the first data storage bank serving as an active bank and rewriting the second data storage bank serving as an inactive bank by writing update data acquired from an outside to the second data storage bank; and an activation execution procedure of switching the active bank 
     An example of a data structure of specification data is a data structure of specification data for program update and is used for a computer that distributes update data to a rewrite target electronic control unit and instructs the rewrite target electronic control unit for installation. The data structure of specification data includes device identification information for identifying the rewrite target electronic control unit and memory type of an non-volatile memory of the electronic control unit corresponding to the device identification information, and is used for the computer to perform processes of: instructing for the installation during travelable, when the memory type of the non-volatile memory of the electronic control unit corresponding to the device identification information is such that the electronic control unit corresponding to the device identification information has as a substantial double-bank as data storage banks; and instructing for the installation during a vehicle being parked, when the memory type of the non-volatile memory of the electronic control unit corresponding to the device identification information is such that the electronic control unit corresponding to the device identification information has as a pseudo double-bank as data storage banks. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Objects, features and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings. In the drawings: 
         FIG. 1  is a diagram illustrating the overall configuration according to an embodiment, 
         FIG. 2  is a diagram illustrating an electrical configuration of a CGW, 
         FIG. 3  is a diagram illustrating an electrical configuration of a DCM, 
         FIG. 4  is a diagram illustrating an electrical configuration of an ECU, 
         FIG. 5  is a diagram illustrating a connection aspect of a power line, 
         FIG. 6  is a diagram illustrating an aspect of packaging reprogramming data and distribution specification data, 
         FIG. 7  is a diagram illustrating rewrite specification data for DCM, 
         FIG. 8  is a diagram illustrating rewrite specification data for CGW, 
         FIG. 9  a diagram illustrating the distribution specification data, 
         FIG. 10  is a diagram illustrating an aspect of unpackaging a distribution package, 
         FIG. 11  is a diagram illustrating an aspect during a normal operation in an embedded type single-bank memory, 
         FIG. 12  is a diagram illustrating an aspect during a rewrite operation in the embedded type single-bank memory, 
         FIG. 13  is a diagram illustrating an aspect during a normal operation in a download type single-bank memory, 
         FIG. 14  is a diagram illustrating an aspect during a rewrite operation in the download type single-bank memory, 
         FIG. 15  is a diagram illustrating an aspect during a normal operation in an embedded type single-bank suspend memory, 
         FIG. 16  is a diagram illustrating an aspect during a rewrite operation in the embedded type single-bank suspend memory, 
         FIG. 17  is a diagram illustrating an aspect during a normal operation in a download type single-bank suspend memory, 
         FIG. 18  is a diagram illustrating an aspect during a rewrite operation in the download type single-bank suspend memory, 
         FIG. 19  is a diagram illustrating an aspect during a normal operation in an embedded type double-bank memory, 
         FIG. 20  is a diagram illustrating an aspect during a rewrite operation in the embedded type double-bank memory, 
         FIG. 21  is a diagram illustrating an aspect during a normal operation in a download type double-bank memory, 
         FIG. 22  is a diagram illustrating an aspect during a rewrite operation in the download type double-bank memory, 
         FIG. 23  is a diagram illustrating an aspect of rewriting an application program, 
         FIG. 24  is a diagram illustrating an aspect of rewriting the application program, 
         FIG. 25  is a diagram illustrating an aspect of rewriting the application program, 
         FIG. 26  is a timing chart illustrating an aspect in which an application program is rewritten by using power supply control, 
         FIG. 27  is a timing chart illustrating an aspect in which the application program is rewritten by using the power supply control, 
         FIG. 28  is a timing chart illustrating an aspect in which the application program is rewritten by using self-retention power, 
         FIG. 29  is a timing chart illustrating an aspect in which the application program is rewritten by using self-retention power, 
         FIG. 30  is a diagram illustrating a phase, 
         FIG. 31  is a diagram illustrating a screen in a normal state, 
         FIG. 32  is a diagram illustrating a screen when a campaign notification occurs, 
         FIG. 33  is a diagram illustrating a screen at the time of the campaign notification, 
         FIG. 34  a diagram illustrating a screen when download is approved, 
         FIG. 35  is a diagram illustrating a screen when the download is approved, 
         FIG. 36  is a diagram illustrating a screen during execution of the download, 
         FIG. 37  is a diagram illustrating a screen during execution of the download, 
         FIG. 38  a diagram illustrating a screen when the download is completed, 
         FIG. 39  a diagram illustrating a screen when installation is approved, 
         FIG. 40  a diagram illustrating a screen when the installation is approved, 
         FIG. 41  is a diagram illustrating a screen during execution of the installation, 
         FIG. 42  is a diagram illustrating a screen during execution of the installation, 
         FIG. 43  a diagram illustrating a screen when activation is approved, 
         FIG. 44  a diagram illustrating a screen when IG is ON, 
         FIG. 45  is a diagram illustrating a screen during a check operation, 
         FIG. 46  is a diagram illustrating a screen during the check operation, 
         FIG. 47  is a functional block diagram of a center device, 
         FIG. 48  is a functional block diagram of the DCM, 
         FIG. 49  is a functional block diagram of the CGW, 
         FIG. 50  is a functional block diagram of the CGW, 
         FIG. 51  is a functional block diagram of the ECU, 
         FIG. 52  is a functional block diagram of an in-vehicle display, 
         FIG. 53  is a functional block diagram of a distribution package transmission determination unit, 
         FIG. 54  is a flowchart illustrating a distribution package transmission determination process, 
         FIG. 55  is a functional block diagram of a distribution package download determination unit, 
         FIG. 56  is a flowchart illustrating a distribution package download determination process, 
         FIG. 57  is a functional block diagram of a write data transfer determination unit, 
         FIG. 58  is a flowchart illustrating a write data transfer determination process, 
         FIG. 59  is a functional block diagram of a write data acquisition determination unit, 
         FIG. 60  is a flowchart illustrating a write data acquisition determination process, 
         FIG. 61  is a functional block diagram of an installation instruction determination unit, 
         FIG. 62  is a flowchart illustrating an installation instruction determination process, 
         FIG. 63  is a diagram illustrating an aspect of giving an instruction for installation, 
         FIG. 64  is a diagram illustrating an aspect of giving an instruction for installation, 
         FIG. 65  is a diagram illustrating an aspect of generating a random number value, 
         FIG. 66  is a functional block diagram of a security access key management unit, 
         FIG. 67  is a flowchart illustrating a security access key generation process, 
         FIG. 68  is a diagram illustrating an aspect of generating a security access key, 
         FIG. 69  is a flowchart illustrating a process of erasing a security access key, 
         FIG. 70  is a diagram illustrating a flow of process related to verification of write data, 
         FIG. 71  is a functional block diagram of a write data verification unit, 
         FIG. 72  is a flowchart illustrating a write data verification process, 
         FIG. 73  is a diagram illustrating an aspect in which a process related to verification of write data is distributed, 
         FIG. 74  is a diagram illustrating an aspect in which the process related to verification of write data is distributed, 
         FIG. 75  is a diagram illustrating an aspect in which the process related to verification of write data is distributed, 
         FIG. 76  is a diagram illustrating an aspect in which the process related to verification of write data is distributed, 
         FIG. 77  is a diagram illustrating a flow of verification of write data and rewriting of an application program, 
         FIG. 78  is a diagram illustrating a flow of verification of the write data and rewriting of the application program, 
         FIG. 79  is a functional block diagram of a data storage bank information transmission control unit, 
         FIG. 80  is a flowchart illustrating a data storage bank information transmission control process, 
         FIG. 81  is a sequence diagram illustrating an aspect of performing a notification of double-bank rewrite information, 
         FIG. 82  is a functional block diagram of a power supply management unit for a non-rewrite target, 
         FIG. 83  is a flowchart illustrating a power supply management process for a non-rewrite target, 
         FIG. 84  is a diagram illustrating transition to an active state, a stop state, and a sleep state, 
         FIG. 85  is a diagram illustrating the transition of the active state, stop state, and sleep state, 
         FIG. 86  is a diagram illustrating a connection aspect of power lines, 
         FIG. 87  is a flowchart illustrating a remaining battery charge monitoring process, 
         FIG. 88  is a functional block diagram of a file transfer control unit, 
         FIG. 89  is a flowchart illustrating a file transfer control process, 
         FIG. 90  is a diagram illustrating an aspect of exchanging files, 
         FIG. 91  is a diagram illustrating an aspect of exchanging files, 
         FIG. 92  is a diagram illustrating divided files and write files, 
         FIG. 93  is a diagram illustrating an aspect in which the CGW transmits a transfer request to the DCM, 
         FIG. 94  is a diagram illustrating an aspect in which the CGW transmits a transfer request to the DCM, 
         FIG. 95  is a diagram illustrating an aspect in which the CGW distributes write data to a rewrite target ECU, 
         FIG. 96  is a diagram illustrating an aspect in which the CGW distributes the write data to the rewrite target ECU, 
         FIG. 97  is a diagram illustrating an aspect in which the CGW distributes the write data to the rewrite target ECU, 
         FIG. 98  is a diagram illustrating a connection aspect of the ECU, 
         FIG. 99  is a functional block diagram of a write data distribution control unit, 
         FIG. 100  is a diagram illustrating a bus load table, 
         FIG. 101  is a diagram illustrating a table to which the rewrite target ECU belongs, 
         FIG. 102  is a flowchart illustrating a write data distribution control process, 
         FIG. 103  is a diagram illustrating an aspect of distributing write data, 
         FIG. 104  is a diagram illustrating an aspect of distributing write data, 
         FIG. 105  is a diagram illustrating an aspect of distributing write data while a vehicle is traveling, 
         FIG. 106  is a diagram illustrating an aspect of distributing write data during parking, 
         FIG. 107  is a diagram illustrating a distribution amount of write data, 
         FIG. 108  is a diagram illustrating a distribution amount of write data, 
         FIG. 109  is a functional block diagram of an activation request instruction unit, 
         FIG. 110  is a flowchart illustrating an activation request instruction process, 
         FIG. 111  is a diagram illustrating an aspect of giving an instruction for an activation request, 
         FIG. 112  is a functional block diagram of an activation execution control unit, 
         FIG. 113  is a flowchart illustrating a rewrite process, 
         FIG. 114  is a flowchart illustrating an activation execution control process, 
         FIG. 115  is a functional block diagram of a rewrite target grouping unit, 
         FIG. 116  is a flowchart illustrating a rewrite target group management process, 
         FIG. 117  is a flowchart illustrating the rewrite target group management process, 
         FIG. 118  a diagram illustrating an aspect of grouping rewrite targets, 
         FIG. 119  is a functional block diagram of a rollback execution control unit, 
         FIG. 120  is a flowchart illustrating a rollback method specifying process, 
         FIG. 121  is a flowchart illustrating a cancellation request determination process, 
         FIG. 122  is a flowchart illustrating the cancellation request determination process, 
         FIG. 123  is a flowchart illustrating the cancellation request determination process, 
         FIG. 124  is a flowchart illustrating the cancellation request determination process, 
         FIG. 125  is a flowchart illustrating the cancellation request determination process, 
         FIG. 126  is a diagram illustrating an aspect of executing rollback, 
         FIG. 127  is a diagram illustrating an aspect of executing the rollback, 
         FIG. 128  is a diagram illustrating an aspect of executing the rollback, 
         FIG. 129  is a diagram illustrating an aspect of executing the rollback, 
         FIG. 130  is a diagram illustrating an aspect of executing the rollback, 
         FIG. 131  is a functional block diagram of a rewrite progress situation display control unit, 
         FIG. 132  is a flowchart illustrating a rewrite progress situation display control process, 
         FIG. 133  is a flowchart illustrating the rewrite progress situation display control process, 
         FIG. 134  is a diagram illustrating a rewrite progress situation screen, 
         FIG. 135  is a diagram illustrating the rewrite progress situation screen, 
         FIG. 136  is a diagram illustrating the rewrite progress situation screen, 
         FIG. 137  is a diagram illustrating the rewrite progress situation screen, 
         FIG. 138  is a diagram illustrating the rewrite progress situation screen, 
         FIG. 139  is a diagram illustrating transition of progress graph display, 
         FIG. 140  is a diagram illustrating the transition of the progress graph display, 
         FIG. 141  is a diagram illustrating the transition of the progress graph display, 
         FIG. 142  is a diagram illustrating the transition of the progress graph display, 
         FIG. 143  is a diagram illustrating a rewrite progress situation screen, 
         FIG. 144  is a functional block diagram of a difference data consistency determination unit, 
         FIG. 145  is a flowchart illustrating a difference data consistency determination process, 
         FIG. 146  is a diagram illustrating an aspect of determining the consistency of difference data, 
         FIG. 147  is a diagram illustrating an aspect of determining the consistency of difference data, 
         FIG. 148  is a functional block diagram of a rewrite execution control unit, 
         FIG. 149  is a flowchart illustrating a normal operation process, 
         FIG. 150  is a flowchart illustrating a rewrite operation process, 
         FIG. 151  is a flowchart illustrating an information notification process, 
         FIG. 152  is a flowchart illustrating a rewrite program verification process, 
         FIG. 153  is a diagram illustrating an aspect of transmitting identification information and write data, 
         FIG. 154  is a diagram illustrating an aspect of transmitting the identification information and the write data, 
         FIG. 155  is a flowchart illustrating an installation instruction process, 
         FIG. 156  is a functional block diagram of a session establishment unit, 
         FIG. 157  a diagram illustrating a configuration of a program, 
         FIG. 158  is a diagram illustrating state transition, 
         FIG. 159  is a diagram illustrating the state transition, 
         FIG. 160  is a diagram illustrating the state transition, 
         FIG. 161  is a diagram illustrating session arbitration, 
         FIG. 162  is a diagram illustrating session arbitration, 
         FIG. 163  is a flowchart illustrating a state transition management process of a first state, 
         FIG. 164  is a flowchart illustrating the state transition management process of the first state, 
         FIG. 165  is a flowchart illustrating the state transition management process of the first state, 
         FIG. 166  is a flowchart illustrating a state transition management process of a second state, 
         FIG. 167  is a flowchart illustrating the state transition management process of the second state, 
         FIG. 168  a diagram illustrating a configuration of a program, 
         FIG. 169  is a diagram illustrating state transition, 
         FIG. 170  is a functional block diagram of a retry point specifying unit, 
         FIG. 171  is a diagram illustrating a configuration of a flash memory, 
         FIG. 172  is a flowchart illustrating a process flag setting process, 
         FIG. 173  is a flowchart illustrating a process flag determination process, 
         FIG. 174  is a flowchart illustrating the process flag determination process, 
         FIG. 175  is a functional block diagram of a progress state synchronization control unit, 
         FIG. 176  is a functional block diagram of the progress state synchronization control unit, 
         FIG. 177  is a diagram illustrating an aspect of transmitting and receiving a progress state signal, 
         FIG. 178  is a flowchart illustrating a progress state synchronization control process, 
         FIG. 179  is a flowchart illustrating the progress state synchronization control process, 
         FIG. 180  is a flowchart illustrating a progress state display process, 
         FIG. 181  is a functional block diagram of a display control information transmission control unit, 
         FIG. 182  is a flowchart illustrating a display control information transmission control process, 
         FIG. 183  is a functional block diagram of a display control information reception control unit, 
         FIG. 184  is a flowchart illustrating a display control information reception control process, 
         FIG. 185  is a diagram illustrating information included in distribution specification data, 
         FIG. 186  is a functional block diagram of a progress display screen display control unit, 
         FIG. 187  is a diagram illustrating rewrite specification data, 
         FIG. 188  is a diagram illustrating a screen during menu selection, 
         FIG. 189  is a diagram illustrating a screen during user selection, 
         FIG. 190  is a diagram illustrating a screen during user registration, 
         FIG. 191  is a flowchart illustrating a progress display screen display control process, 
         FIG. 192  is a flowchart illustrating the progress display screen display control process, 
         FIG. 193  is a diagram illustrating a message frame, 
         FIG. 194  is a diagram illustrating a screen when the activation is approved, 
         FIG. 195  is a diagram illustrating setting of item display availability, 
         FIG. 196  is a diagram illustrating the setting of item display availability, 
         FIG. 197  is a diagram illustrating a screen when activation is approved, 
         FIG. 198  is a diagram illustrating an aspect of data communication, 
         FIG. 199  is a diagram illustrating a message frame during a campaign notification, 
         FIG. 200  is a diagram illustrating a message frame when download is approved, 
         FIG. 201  is a diagram illustrating a message frame when installation is approved, 
         FIG. 202  is a diagram illustrating the message frame when activation is approved, 
         FIG. 203  is a diagram illustrating screen transition, 
         FIG. 204  a diagram illustrating a screen when a campaign notification occurs, 
         FIG. 205  is a diagram illustrating a screen when download is approved, 
         FIG. 206  is a diagram illustrating a screen when the download is approved, 
         FIG. 207  is a diagram illustrating a screen during execution of download, 
         FIG. 208  is a diagram illustrating a screen when download is completed, 
         FIG. 209  is a diagram illustrating a screen when installation is approved, 
         FIG. 210  is a diagram illustrating a screen when activation is approved, 
         FIG. 211  is a functional block diagram of a program update notification control unit, 
         FIG. 212  is a flowchart illustrating a program update notification control process, 
         FIG. 213  is a diagram illustrating an indicator notification aspect, 
         FIG. 214  is a diagram illustrating transition of a notification aspect in a case where a rewrite target is a double-bank memory, 
         FIG. 215  is a diagram illustrating transition of a notification aspect in a case where a rewrite target is a single-bank suspend memory. 
         FIG. 216  is a diagram illustrating transition of a notification aspect in a case where a rewrite target is a single-bank memory, 
         FIG. 217  is a diagram illustrating a connection aspect, 
         FIG. 218  is a functional block of a self-retention power execution control unit in the CGW, 
         FIG. 219  is a functional block of a self-retention power execution control unit in the ECU, 
         FIG. 220  is a flowchart illustrating an execution control process for self-retention power in the CGW, 
         FIG. 221  is a flowchart illustrating an execution control process for self-retention power in the ECU, 
         FIG. 222  is a diagram illustrating a period in which self-retention power is required, 
         FIG. 223  is an overall sequence diagram illustrating an aspect of rewriting the application program, 
         FIG. 224  is an overall sequence diagram illustrating an aspect of rewriting the application program, 
         FIG. 225  is an overall sequence diagram illustrating an aspect of rewriting the application program, 
         FIG. 226  is an overall sequence diagram illustrating an aspect of rewriting the application program, 
         FIG. 227  is an overall sequence diagram illustrating an aspect of rewriting the application program, 
         FIG. 228  is an overall sequence diagram illustrating an aspect of rewriting the application program, 
         FIG. 229  is an overall sequence diagram illustrating an aspect of rewriting the application program, 
         FIG. 230  is an overall sequence diagram illustrating an aspect of rewriting the application program, 
         FIG. 231  is an overall sequence diagram illustrating an aspect of rewriting the application program, 
         FIG. 232  is an overall sequence diagram illustrating an aspect of rewriting the application program, 
         FIG. 233  is an overall sequence diagram illustrating an aspect of rewriting the application program, 
         FIG. 234  is a diagram illustrating the overall configuration of a vehicle information communication system in a first embodiment, 
         FIG. 235  is a diagram illustrating an electrical configuration of a CGW, 
         FIG. 236  is a diagram illustrating an electrical configuration of an ECU, 
         FIG. 237  is a diagram illustrating a connection aspect of power lines, 
         FIG. 238  is a diagram illustrating an aspect of packaging reprogramming data and distribution specification data, 
         FIG. 239  is a diagram illustrating an aspect of unpackaging a distribution package, 
         FIG. 240  is a block diagram illustrating portions of a center device related to respective main functions of a server, 
         FIG. 241  is an image diagram illustrating a flow of a process in the center device, 
         FIG. 242  is a diagram illustrating an example of vehicle configuration information registered in a configuration information DB, 
         FIG. 243  is a diagram illustrating an example of a program or data registered in an ECU reprogramming data DB, 
         FIG. 244  is a diagram illustrating an example of specification data registered in an ECU metadata DB, 
         FIG. 245  is a diagram illustrating an example of vehicle configuration information registered in an individual vehicle information DB, 
         FIG. 246  is a diagram illustrating an example of distribution package data registered in a package DB, 
         FIG. 247  a diagram illustrating an example of campaign data registered in a campaign DB, 
         FIG. 248  is a flowchart illustrating a process of generating a program or data registered in the ECU reprogramming data DB, 
         FIG. 249  is a flowchart illustrating a process of generating an example of specification data registered in the ECU metadata DB, 
         FIG. 250  is a diagram illustrating an example of specification data, 
         FIG. 251  is a diagram illustrating an example of a bus load table, 
         FIG. 252  is a flowchart illustrating a process of generating a distribution package registered in the package DB, 
         FIG. 253  is an image diagram illustrating a content of a package file, 
         FIG. 254  is a sequence diagram illustrating processing procedures executed between a center device and a vehicle-side system in a second embodiment, 
         FIG. 255  is a flowchart illustrating a process performed by the center device, 
         FIG. 256  is an image diagram illustrating contents of processes performed in steps D 6  and D 7  in the flowchart of  FIG. 248 . 
         FIG. 257  is a flowchart illustrating a process in a case where a hash value is transmitted from the vehicle-side system to the center device, 
         FIG. 258  is a sequence diagram illustrating processing procedures executed between a center device and a vehicle-side system in a third embodiment, 
         FIG. 259  is a flowchart illustrating a process performed by the center device, 
         FIG. 260  is a sequence diagram illustrating a state in which the center device notifies an EV vehicle and a conventional vehicle by using an SMS, 
         FIG. 261  is a sequence diagram illustrating processing procedures executed between a center device and a vehicle-side system in a fourth embodiment, 
         FIG. 262  is an image diagram illustrating processes performed among a supplier, a center device, and a vehicle-side system in a fifth embodiment, 
         FIG. 263  is a sequence diagram (first) illustrating processing procedures performed among the supplier, the center device, and the vehicle-side system, 
         FIG. 264  is a sequence diagram (second) illustrating the processing procedures performed among the supplier, the center device, and the vehicle-side system, 
         FIG. 265  is a sequence diagram (third) illustrating the processing procedures performed among the supplier, the center device, and the vehicle-side system, 
         FIG. 266  is a diagram illustrating a modification example (first) of the first embodiment and illustrating a data format of the package DB in a case where a plurality of packages correspond to a single campaign, 
         FIG. 267  is a diagram illustrating a data format of the campaign DB in a case where a plurality of packages correspond to a single campaign, 
         FIG. 268  is a diagram corresponding to  FIG. 242  in a case where specification data is generated for each group, 
         FIG. 269  is a diagram corresponding to  FIG. 245  in a case where a distribution package is generated for each group, and 
         FIG. 270  is a diagram illustrating a modification example (second) of the first embodiment and illustrating a process content in package generation tool. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     In recent years, the scale of a program for vehicle control, diagnosis, and the like, installed in an electronic control device (hereinafter, referred to as an electronic control unit (ECU)) of a vehicle, has been increased due to the diversification of vehicle control such as a driving support function and an autonomous driving function. An opportunity to rewrite (reprogram) a program of an ECU has been increased in accordance with upgrading based on functional improvement. On the other hand, a technique for connected cars has also been spread with the progress of communication networks or the like. In light of such circumstances, for example, there is a proposed technique in which a vehicle master device as a relay device is provided on a vehicle side, and the vehicle master device distributes update data received wirelessly from a center device to a rewrite target ECU and instructs the rewrite target ECU for write of the update data such that a program of the rewrite target ECU is rewritten through Over The Air (OTA). 
     In the proposed technique, an ECU as a rewrite target ECU has a plurality of data storage banks. For example, a rewrite target ECU having a bank-A and a bank-B of a double-bank writes update data for a new program to the bank-B, switches the bank-B, in which the update data for the new program has been written, from an inactive bank to an active bank, and starts the bank-B switched from the inactive bank to the active bank, and thereby executes the new program. In this regard, when data update for a rewrite target ECU is performed due to a user&#39;s operation, it is necessary to appropriately complete the rewriting of a program and execute update data for such a rewrite target ECU having a plurality of data storage banks. 
     The present disclosure has been made in light of the above circumstances and an object thereof is to provide an electronic control unit, a vehicle electronic control system, a rewrite execution method, a rewrite execution program, and a data structure of specification data that can appropriately complete rewriting of a program. 
     According to an aspect of the present disclosure, an installation execution unit operates at least one of an application program or parameter data stored in a first data storage bank serving as an active bank and rewrites a second data storage bank serving as an inactive bank by writing, to the second data storage bank, update data acquired from an external device. An activation execution unit switches the active bank from the first data storage bank to the second data storage bank. The installation execution unit rewrites the second data storage bank during a vehicle being travelable or parked. The activation execution unit switches the active bank from the first data storage bank to the second data storage bank during the vehicle being parked. 
     The installation is executed during the vehicle being travelable or parked, and the activation is executed during the vehicle being parked. In a configuration having a plurality of data storage banks, it is possible to appropriately complete rewriting of a program. 
     Hereinafter, one embodiment will be described with reference to the drawings. A vehicle program rewriting system (corresponding to a vehicle electronic control system) is a system in which application programs for vehicle control, diagnosis, and the like, installed in an electronic control device (hereinafter referred to as an electronic control unit (ECU)) can be rewritten through Over The Air (OTA). In the present embodiment, a case where an application program is rewritten in a wired or wireless manner will be described, but the present disclosure may be applied to a case where data used in various applications, such as map data used in a map application, and control parameters used in an ECU is rewritten in a wired or wireless manner. 
     The rewriting of an application program in a wire manner includes not only acquiring and rewriting the application program from the outside of a vehicle in the wired manner but also acquiring and rewriting various pieces of data used when the application program is executed from the outside of the vehicle in the wire manner. The rewriting of the application program in a wireless manner includes not only acquiring and rewriting an application program from the outside of a vehicle in the wireless manner but also acquiring and rewriting various pieces of data used when the application program is executed from the outside of the vehicle in the wireless manner. 
     As illustrated in  FIG. 1 , a vehicle program rewriting system  1  includes a center device  3  on a communication network  2  side, a vehicle-side system  4  on a vehicle side, and a display terminal  5 . The communication network  2  is configured to include, for example, a mobile communication network such as a 4G line, the Internet, and Wireless Fidelity (Wi-Fi (registered trademark)). In the present embodiment, the following description will focus on a configuration of the vehicle side, and a configuration of the center device  3  will be described in detail with reference to  FIGS. 234 to 270 . 
     The display terminal  5  is a terminal having a function of receiving operation input from a user and a function of displaying various screens, and is, for example, a mobile terminal  6  such as a smartphone or a tablet computer that can be carried by a user, and an in-vehicle display  7  disposed in a vehicle compartment. The mobile terminal  6  can perform data communication with the center device  3  via the communication network  2  as long as the mobile terminal  6  is within a communication range of a mobile communication network. The in-vehicle display  7  is connected to the vehicle-side system  4 , and may also have a navigation function. The in-vehicle display  7  may be an in-vehicle display ECU having an ECU function, or may have a function of controlling display on a center display, a meter display, or the like. 
     As long as a user is located outside the vehicle compartment and is within the communication range of the mobile communication network, the user can perform operation input while checking various screens related to rewriting of an application program with the mobile terminal  6 , and can perform a procedure related to the rewriting of the application program. In the vehicle compartment, the user can perform operation input while checking various screens related to rewriting of the application program with the in-vehicle display  7 , and can perform a procedure related to rewriting of the application program. That is, the user can use the mobile terminal  6  and the in-vehicle display  7  separately outside the vehicle compartment and in the vehicle compartment, and can perform a procedure related to rewriting of the application program. 
     The center device  3  controls a program update function of the communication network  2  side in the vehicle program rewriting system  1 , and functions as an OTA center. The center device  3  includes a file server  8 , a web server  9 , and a management server  10 , and each of the servers  8  to  10  is configured to be able to perform data communication with each other. That is, the center device  3  is configured to include a plurality of different servers for each function. 
     The file server  8  is a server that manages a file of an application program distributed from the center device  3  to the vehicle-side system  4 . The file server  8  manages update data (hereinafter, also referred to as reprogramming data or write data) provided from a supplier or the like, which is a provider of an application program distributed from the center device  3  to the vehicle-side system  4 , distribution specification data provided from an original equipment manufacturer (OEM), vehicle conditions acquired from the vehicle-side system  4 , and the like. The file server  8  can perform data communication with the vehicle-side system  4  via the communication network  2 , and transmits a distribution package in which the reprogramming data and the distribution specification data are packaged into one file to the vehicle-side system  4  when a download request for the distribution package is generated. 
     The web server  9  is a server that manages web information. The web server  9  transmits web data managed thereby in response to a request from a web browser of the mobile terminal  6  or the like. The management server  10  is a server that manages personal information of a user registered in a service of rewriting an application program, a rewrite history of an application program for each vehicle, and the like. 
     The vehicle-side system  4  has a master device  11  (corresponding to a vehicle master device). The master device  11  includes a data communication module (DCM)  12  (corresponding to an in-vehicle communication device) and a central gate way (CGW)  13  (corresponding to a vehicle gateway device). The DCM  12  and the CGW  13  are connected to each other via a first bus  14  to be able to perform data communication. The DCM  12  performs data communication with the center device  3  via the communication network  2 . When the DCM  12  downloads the distribution package from the file server  8 , the DCM extracts write data from the downloaded distribution package and transfers the extracted write data to the CGW  13 . 
     The CGW  13  has a data relay function, and, when the write data is acquired from the DCM  12 , the CGW instructs a rewrite target ECU that is a rewrite target of an application program to write the acquired write data, and distributes the write data to the rewrite target ECU. When writing of the write data has been completed in the rewrite target ECU and rewriting of the application program has been completed, the CGW  13  instructs the rewrite target ECU to perform activation for validating the application program after being rewritten. 
     The master device  11  controls a program update function of the vehicle side in the vehicle program rewriting system  1 , and functions as an OTA master. In  FIG. 1 , although the DCM  12  and the in-vehicle display  7  are configured to be connected to the same first bus  14  as an example, the DCM  12  and the in-vehicle display  7  may be configured to be connected to separate buses. The CGW  13  may have some or all of the functions of the DCM  12 , or the DCM  12  may have some or all of the functions of the CGW  13 . That is, in the master device  11 , function sharing between the DCM  12  and the CGW  13  may be configured in any manner. The master device  11  may be configured with two ECUs such as the DCM  12  and the CGW  13 , or may be configured with a single integrated ECU having the functions of the DCM  12  and the functions of the CGW  13 . 
     In addition to the first bus  14 , a second bus  15 , a third bus  16 , a fourth bus  17 , and a fifth bus  18  are connected to the CGW  13  as buses inside the vehicle, and various ECUs  19  are connected via the buses  15  to  17 , and a power supply management ECU  20  is connected via the bus  18 . 
     The second bus  15  is, for example, a body system network bus. The ECUs  19  connected to the second bus  15  are ECUs controlling a body system. The ECUs controlling the body system include, for example, a door ECU controlling locking/unlocking of a door, a meter ECU controlling display on the meter display, an air conditioner ECU controlling driving of an air conditioner, a window ECU controlling opening and closing of a window, and a security ECU driven to prevent theft of the vehicle. 
     The third bus  16  is, for example, a traveling system network bus. The ECUs  19  connected to the third bus  16  are ECUs controlling a traveling system. The ECUs controlling the traveling system include, for example, an engine ECU controlling driving of an engine, a brake ECU controlling driving of a brake, an electronic controlled transmission (ECT) ECU controlling driving of an automatic transmission, and a power steering ECU controlling a driving of a power steering. 
     The fourth bus  17  is, for example, a multimedia system network bus. The ECUs  19  connected to the fourth bus  17  are ECUs controlling a multimedia system. The ECUs controlling the multimedia system include, for example, a navigation ECU controlling a navigation system, and an ETC ECU controlling an electronic toll collection system (ETC) (registered trademark). The buses  15  to  17  may be system buses other than the body system network bus, the traveling system network bus, and the multimedia system network bus. The number of buses and the number of the ECUs  19  are not limited to the exemplified configuration. The power supply management ECU  20  is an ECU that manages power to be supplied to the DCM  12 , the CGW  13 , the various ECUs  19 , and the like. 
     A sixth bus  21  is connected to the CGW  13  as a bus outside the vehicle. A data link coupler (DLC) connector  22  to which a tool  23  (corresponding to a service tool) is detachably connected is connected to the sixth bus  21 . The buses  14  to  18  inside the vehicle and the bus  21  outside the vehicle are configured with, for example, Controller Area Network (CAN) (registered trademark) buses, and the CGW  13  performs data communication with the DCM  12 , the various ECUs  19 , and the tool  23  in accordance with the CAN data communication standard and the diagnosis communication standard (Unified Diagnosis Services (UDS): ISO14229). The DCM  12  and the CGW  13  may be connected to each other via Ethernet, and the DLC connector  22  and the CGW  13  may be connected to each other via Ethernet. 
     When write data is received from the CGW  13 , the rewrite target ECU  19  writes the received write data into a flash memory (corresponding to a non-volatile memory) to rewrite an application program. In the above configuration, when a request for acquiring write data is received from the rewrite target ECU  19 , the CGW  13  functions as a reprogramming master that distributes the write data to the rewrite target ECU  19 . When the write data is received from the CGW  13 , the rewrite target ECU  19  functions as a reprogramming slave that writes the received write data into the flash memory to rewrite the application program. 
     As an aspect of rewriting the application program, there are a wired rewrite aspect and a wireless rewrite aspect. The aspect in which the application program is rewritten in a wired manner is an aspect in which the rewrite target ECU  19  is rewritten by using an application program acquired from the outside of the vehicle in a wired manner. Specifically, when the tool  23  is connected to the DLC connector  22 , the tool  23  transfers the write data to the CGW  13 . The CGW  13  functions as a gateway, transmits a wired rewrite request to the rewrite target ECU  19 , instructs the rewrite target ECU  19  to write (install) the write data, and distributes the write data transferred from the tool  23  to the rewrite target ECU  19 . Distributing the write data to the rewrite target ECU  19  is to relay the write data. 
     The aspect in which the application program is rewritten in a wireless manner is an aspect in which the rewrite target ECU  19  is rewritten by using an application program acquired from the outside of the vehicle in a wireless manner. Specifically, when a distribution package is downloaded from the file server  8 , the DCM  12  extracts write data from the downloaded distribution package, and transfers the write data to the CGW  13 . The CGW  13  functions as a rewrite tool, instructs the rewrite target ECU  19  to write (install) the write data, and distributes the write data transferred from the DCM  12  to the rewrite target ECU  19 . 
     Aspects of diagnosing the ECU  19  include a wired diagnosis aspect and a wireless diagnosis aspect. The wired diagnosis aspect is an aspect in which the ECU  19  is diagnosed from the outside of the vehicle in a wired manner. Specifically, when the tool  23  is connected to the DLC connector  22 , the tool  23  transfers a diagnosis request to the CGW  13 . The CGW  13  functions as a gateway, transmits a diagnosis request to the diagnosis target ECU  19 , and distributes a diagnosis command transferred from the tool  23  to a diagnosis target ECU  19 . The diagnosis target ECU  19  performs a diagnosis process in accordance with the diagnosis command received from the CGW  13 . 
     The wireless diagnosis aspect is an aspect in which the ECU  19  is diagnosed from the outside of the vehicle in a wireless manner. Specifically, when a diagnosis command is transmitted as a diagnosis request from the center device  3  to the DCM  12 , the DCM  12  transfers the diagnosis command to the CGW  13 . The CGW  13  functions as a gateway and distributes the diagnosis command as a diagnosis request to the diagnosis target ECU  19 . The diagnosis target ECU performs a diagnosis process in accordance with the diagnosis command received from the CGW  13 . 
     As illustrated in  FIG. 2 , the CGW  13  includes a microcomputer  24 , a data transfer circuit  25 , a power supply circuit  26 , and a power detection circuit  27  as electrical functional blocks. The microcomputer  24  includes a central processing unit (CPU)  24   a , a read only memory (ROM)  24   b , a random access memory (RAM)  24   c , and a flash memory  24   d . The flash memory  24   d  includes a secure area in which information cannot be read from the outside of the CGW  13 . The microcomputer  24  performs various processes by executing various control programs stored in a non-transitory tangible storage medium, and controls an operation of the CGW  13 . 
     The data transfer circuit  25  controls data communication with the buses  14  to  18  and  21  in accordance with the CAN data communication standard and the diagnosis communication standard. The power supply circuit  26  receives battery power (hereinafter, referred to as +B power), accessory power (hereinafter, referred to as ACC power), and ignition power (hereinafter, referred to as IG power). The power detection circuit  27  detects a voltage value of the +B power, a voltage value of the ACC power, and a voltage value of the IG power received by the power supply circuit  26 , compares the detected voltage values with predetermined voltage threshold values, and outputs comparison results to the microcomputer  24 . The microcomputer  24  determines whether the +B power, the ACC power, and the IG power supplied to the CGW  13  from the outside are normal or abnormal on the basis of the comparison results that are input from the power detection circuit  27 . 
     As illustrated in  FIG. 3 , the DCM  12  includes a microcomputer  28 , a radio circuit  29 , a data transfer circuit  30 , a power supply circuit  31 , and a power detection circuit  32  as electrical functional blocks. The microcomputer  28  includes a CPU  28   a , a ROM  28   b , a RAM  28   c , and a flash memory  28   d . The flash memory  28   d  includes a secure area in which information cannot be read from the outside of the DCM  12 . The microcomputer  28  performs various processes by executing various control programs stored in a non-transitory tangible storage medium, and controls an operation of the DCM  12 . The flash memory storing data to be downloaded from the center device  3  may be provided in the CGW  13 . 
     The radio circuit  29  controls data communication with the center device  3  via the communication network  2 . The data transfer circuit  30  controls data communication with the bus  14  in accordance with the CAN data communication standard. The power supply circuit  31  receives +B power, ACC power, and IG power. The power detection circuit  32  detects a voltage value of the +B power, a voltage value of the ACC power, and a voltage value of the IG power received by the power supply circuit  31 , compares the detected voltage values with predetermined voltage threshold values, and outputs comparison results to the microcomputer  28 . The microcomputer  28  determines whether the +B power, the ACC power, and the IG power supplied to the DCM  12  from the outside are normal or abnormal on the basis of the comparison results that are input from the power detection circuit  32 . 
     The DCM  12  has a vehicle position detection function of detecting a vehicle position, for example, by using a global positioning system (GPS). The flash memory  28   d  of the DCM  12  has a memory capacity sufficient to store a distribution package downloaded from the center device  3  and has a memory capacity larger than that of the flash memory  24   d  of the CGW  13 . That is, since the flash memory  28   d  of the DCM  12  has a sufficient memory capacity, even though the flash memory  24   d  of the CGW  13  does not have a sufficient memory capacity, the master device  11  can download the distribution package from the center device  3  and store the downloaded distribution package in the DCM  12 . 
     As illustrated in  FIG. 4 , the ECU  19  includes a microcomputer  33 , a data transfer circuit  34 , a power supply circuit  35 , and a power detection circuit  36  as electrical functional blocks. The microcomputer  33  includes a CPU  28   a , a ROM  28   b , a RAM  33   c , and a flash memory  28   d . The flash memory  28   d  includes a secure area in which information cannot be read from the outside of the ECU  19 . The microcomputer  33  performs various processes by executing various control programs stored in a non-transitory tangible storage medium, and controls an operation of the ECU  19 . 
     The data transfer circuit  34  controls data communication with the buses  15  to  17  in accordance with the CAN data communication standard. The power supply circuit  35  receives +B power, ACC power, and IG power. The power detection circuit  36  detects a voltage value of the +B power, a voltage value of the ACC power, and a voltage value of the IG power received by the power supply circuit  35 , compares the detected voltage values with predetermined voltage threshold values, and outputs comparison results to the microcomputer  33 . The microcomputer  33  determines whether the +B power, the ACC power, and the IG power supplied to the ECU  19  from the outside are normal or abnormal on the basis of the comparison results that are input from the power detection circuit  27 . The ECUs  19  fundamentally have the same configuration except that loads such as sensors or actuators connected thereto are different from each other. 
     The in-vehicle display  7  has the same configuration as that of the ECU  19  illustrated in  FIG. 4 . The power supply management ECU  20  has the same configuration as that of the ECU  19  illustrated in  FIG. 4 . The power supply management ECU  20  is connected to a power supply control circuit  43  which will be described later so as to enable data communication therebetween. 
     As illustrated in  FIG. 5 , the power supply management ECU  20 , the CGW  13 , and the ECU  19  are connected to a +B power line  37 , an ACC power line  38 , and an IG power line  39  that are power supply lines. The +B power line  37  is connected to a positive electrode of a vehicle battery  40 . The ACC power line  38  is connected to the positive electrode of the vehicle battery  40  via an ACC switch  41 . When the user performs an ACC operation, the ACC switch  41  switches from an OFF state to an ON state, and an output voltage of the vehicle battery  40  is applied to the ACC power line  38 . For example, in a case of a vehicle of the type to insert a key into an insertion port, the ACC operation is an operation of rotating the key from an “OFF” position to an “ACC” position by inserting the key into the insertion port, and, in a case of a vehicle of the type to press a start button, the ACC operation is an operation of pressing the start button once. 
     The IG power line  39  is connected to the positive electrode of the vehicle battery  40  via an IG switch  42 . When the user performs an IG operation, the IG switch  42  switches from an OFF state to an ON state, and an output voltage of the vehicle battery  40  is applied to the IG power line  39 . For example, in a case of a vehicle of the type to insert a key into an insertion port, the IG operation is an operation of rotating the key from an “OFF” position to an “ON” position by inserting the key into the insertion port, and, in a case of a vehicle of the type to press a start button, the IG operation is an operation of pressing the start button twice. A negative electrode of the vehicle battery  40  is grounded. 
     When both of the ACC switch  41  and the IG switch  42  are in an OFF state, only the +B power is supplied to the vehicle-side system  4 . The state in which only the +B power is supplied to the vehicle-side system  4  will be referred to as a +B power supply state. When the ACC switch  41  is in an ON state and the IG switch  42  is in an OFF state, the ACC power and the +B power are supplied to the vehicle-side system  4 . The state in which the ACC power and the +B power are supplied to the vehicle-side system  4  will be referred to as an ACC power supply state. When of both the ACC switch  41  and the IG switch  42  are in an ON state, the +B power, the ACC power, and the IG power are supplied to the vehicle-side system  4 . The state in which the +B power, the ACC power, and the IG power are supplied to the vehicle-side system  4  will be referred to as an IG power supply state. In addition to each of the above-described power supply states, a power supply state or the like for providing power suitable for program update in a wireless manner is also conceivable. 
     The ECUs  19  have different start conditions depending on power supply states, and are classified as a +B power ECU that is started in the +B power supply state, an ACC ECU that is started in the ACC power supply state, and an IG ECU that is started in the IG power supply state. For example, the ECU  19  driven in an application such as vehicle theft is classified as the +B power ECU. For example, the ECU  19  driven in a non-traveling application such as an audio is classified as the ACC ECUs. For example, the ECU  19  driven in a traveling application such as engine control is classified as the IG ECU. 
     The +B power ECU is connected to the +B power line  37 , the ACC power line  38 , and the IG power line  39 , and is configured to select the +B power line  37  in the +B power supply state, select the ACC power line  38  in the ACC power supply state, and select the IG power line  39  in the IG power supply state. The ACC ECU is connected to the ACC power line  38  and the IG power line  39 , and is configured to select the ACC power line  38  in the ACC power supply state, and select the IG power line  39  in the IG power supply state. The IG ECU is connected to the IG power line  39 . 
     The CGW  13  transmits a start request to the ECU  19  that is in a sleep state, and thus causes the ECU  19  that is a transmission destination of the start request to transition from the sleep state to an active state. The CGW  13  also transmits a sleep request to the ECU  19  that is in an active state, and thus causes the ECU  19  that is a transmission destination of the sleep request to transition from the active state to a sleep state. The CGW  13  can cause a specific ECU  19  to transition to an active state or a sleep state, for example, by making waveforms of the transmission signals to be transmitted to the buses  15  to  17  different from each other. That is, a start request waveform and a sleep request waveform are predefined for each ECU  19 , and the ECU  19  transitions from the sleep state to the active state when a start request waveform conforming thereto is received, and transitions from the active state to the sleep state when a sleep request waveform conforming thereto is received from the CGW  13 . 
     For example, in a case where an ECU (ID 1 ) and an ECU (ID 2 ) are in the active state, the CGW  13  transmits a first waveforms, and thus causes the ECU (ID 1 ) to transition from the active state to the sleep state and maintains the ECU (ID 2 ) in the active state. In a case where the ECU (ID 1 ) and the ECU (ID 2 ) are in the active state, the CGW  13  transmits a second waveform, and thus maintains the ECU (ID 1 ) in the active state and causes the ECU (ID 2 ) to transition from the active state to the sleep state. 
     The power supply control circuit  43  is connected in parallel to the ACC switch  41  and the IG switch  42 . The CGW  13  transmits a power supply control request to the power supply management ECU  20  and causes the power supply management ECU  20  to control the power supply control circuit  43 . That is, the CGW  13  transmits a power supply start request as the power supply control request to the power supply management ECU  20 , to connect the ACC power line  38  or the IG power line  39  to the positive electrode of the vehicle battery  40  in the power supply control circuit  43 . In this state, the ACC power or IG power is supplied to the vehicle-side system  4  even though the ACC switch  41  or the IG switch  42  is turned off. The CGW  13  transmits a power supply stop request as the power supply control request to the power supply management ECU  20 , to disconnect the ACC power line  38  or IG power line  39  from the positive electrode of the vehicle battery  40  in the power supply control circuit  43 . 
     Each of the DCM  12 , the CGW  13 , the ECU  19 , and the power supply management ECU  20  has a self-retention power circuit, and has a self-retention power function of retaining power supplied from the vehicle battery  40 . That is, when vehicle power switches from the ACC power or the IG power to the +B power in the active state, the DCM  12 , the CGW  13 , the ECU  19 , and the power supply management ECU  20  do not transition from the active state to the stop state or the sleep state immediately after the switching, but continue the active state for a predetermined time (for example, a few minutes) with power supplied from the vehicle battery  40  and thus self-retain drive power. The DCM  12 , the CGW  13 , the ECU  19 , and the power supply management ECU  20  transition from the active state to the stop state or the sleep state when a predetermined time has elapsed immediately after the vehicle power switches from the ACC power or IG power to the +B power. For example, in the ECU  19  of the engine control system, the self-retention power function is activated after the vehicle power switches from the ACC power or the IG power to the +B power, and thus stores various pieces of data regarding the engine control acquired during traveling of the vehicle as a log. 
     Next, a distribution package distributed from the center device  3  to the master device  11  will be described. As illustrated in  FIG. 6 , in the vehicle program rewriting system  1 , reprogramming data including write data provided from a supplier as a provider of an application program and rewrite specification data (corresponding to specification data) provided from an OEM is generated. The rewrite specification data may be generated by the center device  3 . The write data provided from the supplier includes difference data corresponding to a difference between an old application program and a new application program, and the entire data corresponding to the whole of the new application program. The difference data or the entire data may be compressed by using a well-known data compression technique.  FIG. 6  exemplifies a case where difference data is provided as write data from suppliers A to C, and reprogramming data is generated from encrypted difference data and an authenticator of the ECU (ID 1 ) provided from the supplier A, encrypted difference data and an authenticator of the ECU (ID 2 ) provided from the supplier B, and encrypted difference data and an authenticator of the ECU (ID 3 ) provided from the supplier C, and rewrite specification data provided from the OEM. 
     The authenticator is data added to each piece of write data in order to verify the integrity of the difference data, and is generated from, for example, an ECU (ID), key information linked to the ECU (ID), and difference data. Here, write data for rollback to an old version may be included in the reprogramming data in preparation for a case where rewriting of an application program is cancelled halfway. 
     The rewrite specification data provided from the OEM includes, as information related to rewriting of the application program, information for specifying the rewrite target ECU  19 , information for specifying a rewrite order when there are a plurality of rewrite target ECUs  19 , information for specifying a rollback method described later, and the like. The rewrite specification data is data defining an operation related to rewriting in the DCM  12 , the CGW  13 , the rewrite target ECU  19 , and the like. The rewrite specification data is classified into DCM rewrite specification data used by the DCM  12  and CGW rewrite specification data used by the CGW  13 . 
     As illustrated in  FIG. 7 , the DCM rewrite specification data includes specification data information and ECU information. The specification data information includes address information and a file name. The ECU information includes address information, or the like referenced when an update program (write data) of each rewrite target ECU  19  is transmitted to the CGW  13  by the number of rewrite target ECUs  19 . Specifically, the ECU information includes at least an ID (ECU (ID)) for identifying an ECU, a reference address (update program acquisition address) for acquiring an update program, an update program size, a reference address (rollback program acquisition address) for acquiring a rollback program, and a rollback program size. The rollback program is a program (write data) for returning an application program to an original version when rewriting of the application program is canceled halfway. 
     As illustrated in  FIG. 8 , the CGW rewrite specification data includes group information, a bus load table, a battery load, a vehicle condition during rewriting, and ECU information. The CGW rewrite specification data may include rewrite procedure information, display scene information, and the like in addition to the information. The group information is information indicating a group to which the rewrite target ECU  19  belongs and a rewrite order, and defines that application programs are rewritten in an order of the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ) as first group information, and that application programs are rewritten in an order of an ECU (ID 4 ), an ECU (ID 5 ), and an ECU (ID 6 ) as second group information, for example. The bus load table is a table illustrated in  FIG. 100  which will be described later, and details thereof will be described later. The battery load is information indicating a lower limit value of a remaining battery charge of the vehicle battery  40  allowable in the vehicle. The vehicle condition during rewriting is information indicating in what kind of vehicle condition rewriting is performed. 
     The ECU information is information regarding the rewrite target ECU  19 , and includes at least an ECU_ID (corresponding to device identification information), a connection bus (corresponding to bus identification information), a connection power supply, security access key information, a memory type, a rewrite method, a self-retention power time, rewrite bank information, an update program version, an update program acquisition address, an update program size, a rollback program version, a rollback program acquisition address, a rollback program size, and a write data type. 
     The connection bus indicates a bus to which the ECU  19  is connected. The connection power supply indicates a power line to which the ECU  19  is connected. The security access key information indicates key information used for authentication performed by the CGW  13  in order to access the rewrite target ECU  19 , and includes a random number value or unique information, a key pattern, and a decryption operation pattern. The memory type indicates whether a memory mounted on the rewrite target ECU  19  is a single-bank memory, a single-bank suspend memory (also referred to as a pseudo-double-bank memory), or a double-bank memory. The rewrite method indicates whether the rewriting is performed on the basis of self-retention power or power supply control. The self-retention power time indicates a time for continuing the self-retention power when the rewrite method is rewriting based on self-retention power. The rewrite bank information indicates which bank is an active bank and which bank is an inactive bank. The active bank is also referred to as a start bank, and the inactive bank is also referred to as a rewrite bank. 
     The update program version indicates a version of an update program. The update program acquisition address indicates an address of the update program. The update program size indicates a data size of the update program. The rollback program version indicates a version of a rollback program. The rollback program acquisition address indicates an address of the rollback program. The rollback program size indicates a data size of the rollback program. The write data type indicates whether the write data is difference data or the entire data. In addition to these pieces of information, the rewrite specification data may include information uniquely defined by the system. 
     When the DCM rewrite specification data is acquired, the DCM  12  analyzes the acquired DCM rewrite specification data. When the DCM rewrite specification data is analyzed, the DCM  12  controls operations related to rewriting such as acquiring write data from an address in which an update program of the rewrite target ECU  19  is stored and transferring the acquired write data to the CGW  13 . 
     When the CGW rewrite specification data is acquired, the CGW  13  analyzes the acquired CGW rewrite specification data. When the CGW rewrite specification data is analyzed, the CGW  13  controls operations related to rewriting such as requesting the DCM  12  to transfer a predetermined size of an update program of the rewrite target ECU  19  in accordance with the analysis result, or distributing the write data to the rewrite target ECU  19  in a designated order. 
     In the file server  8 , the above-described reprogramming data is registered, and the distribution specification data provided from the OEM is registered. The distribution specification data provided from the OEM is data defining an operation related to display of various screens in the display terminal  5 . As illustrated in  FIG. 9 , the distribution specification data includes language information, a display text, package information, image data, a display pattern, a display control program, and the like. 
     When the distribution specification data is acquired from the CGW  13 , the display terminal  5  analyzes the acquired distribution specification data, and controls display of various screens according to the analysis result. For example, the display terminal  5  superimposes a display text acquired from the distribution specification data on a display frame stored in advance, and executes a display control program acquired from the distribution specification data. In addition to these pieces of information, the distribution specification data may include information uniquely defined by the system. 
     When the reprogramming data and the distribution specification data are registered, the file server  8  encrypts the registered reprogramming data, and generates a distribution package storing a package authenticator for authenticating the package, the encrypted reprogramming data, and the distribution specification data. The authenticator is data added to verify the integrity of the reprogramming data and the distribution specification data, and is generated from, for example, key information, the reprogramming data, and the distribution specification data linked to the CGW  13 . When a download request for the distribution package is received from the outside, the file server  8  transmits the distribution package to the DCM  12 . In  FIG. 6 , a case is exemplified in which the file server  8  generates the distribution package storing the reprogramming data and the distribution specification data and transmits the reprogramming data and the distribution specification data to the DCM  12  as a single file together, but the reprogramming data and the distribution specification data may be transmitted to the DCM  12  as separate files. That is, the file server  8  may transmit the distribution specification data to the DCM  12  first, and may transmit the reprogramming data to the DCM  12  later. In this case, an authenticator may be added to each of the distribution specification data and the reprogramming data. 
     As illustrated in  FIG. 10 , when the distribution package is downloaded from the file server  8 , the DCM  12  verifies the integrity of the encrypted reprogramming data by using the package authenticator stored in the downloaded distribution package. The DCM  12  decrypts the encrypted reprogramming data when the verification result is positive. When the encrypted reprogramming data is decrypted, the DCM  12  unpacks (hereinafter, also referred to as unpackages) the decrypted reprogramming data, and divionally extracts the encrypted difference data, the authenticator, the DCM rewrite specification data, and the CGW rewrite specification data.  FIG. 10  illustrates a case where the encrypted difference data and the authenticator of the ECU (ID 1 ), the encrypted difference data and the authenticator of the ECU (ID 2 ), the encrypted difference data and the authenticator of the ECU (ID 3 ), the DCM rewrite specification data, and the CGW rewrite specification data are divisionally extracted. 
     Next, the flash memory  33   d  of the ECU  19  will be described with reference to  FIGS. 11 to 22 . The flash memory  33   d  of the ECU  19  is classified into a single-bank memory having a single flash bank, a single-bank suspend memory having pseudo-double flash banks, and a double-bank memory having double substantial flash banks depending on memory configurations. Thereafter, the ECU  19  equipped with the single-bank memory will be referred to as the single-bank memory ECU, the ECU  19  equipped with the single-bank suspend memory will be referred to as a single-bank suspend memory ECU, and the ECU  19  equipped with the double-bank memory will be referred to as a double-bank memory ECU. 
     Since the single-bank memory has a single flash bank, there is no concept of an active bank and an inactive bank, and an application program cannot be rewritten while the application program is being executed. On the other hand, since the single-bank suspend memory or the double-bank memory has double flash banks, there is a concept of an active bank and an inactive bank, and an application program in the inactive bank can be rewritten while the application program in the active bank is being executed. Since the double-bank memory has double flash banks that are completely separated from each other, an application program can be rewritten at any timing, for example, when the vehicle is traveling. Since the single-bank suspend memory has a configuration in which the single-bank memory is divided into pseudo-double banks, there are restrictions on a timing at which reading and writing can be normally performed, and an application program cannot be rewritten while the vehicle is traveling, and the application program can be rewritten while the IG power is turned off and the vehicle is parked. 
     Each of the single-bank memory, the single-bank suspend memory, and the double-bank memory includes a reprogramming firmware embedded type (hereinafter, referred to as the embedded type) in which reprogramming firmware is embedded, and a reprogramming firmware download type (hereinafter, referred to as the download type) in which the reprogramming firmware is downloaded from the outside. The reprogramming firmware is firmware for rewriting an application program. 
     A configuration of each flash memory will be described below in order. 
     (A) Single-Bank Memory 
     (A-1) Embedded Type Single-Bank Memory 
     The embedded type single-bank memory will be described with reference to  FIGS. 11 and 12 . The embedded type single-bank memory has a difference engine work area, an application program area, and a boot program area. Version information, parameter data, an application program, firmware, and a normal time vector table are located in the application program area. A boot program, a progress state point  2 , a progress state point  1 , start determination information, wireless reprogramming firmware, wired reprogramming firmware, a start determination program, and a boot time vector table are located in the boot area. 
     As illustrated in  FIG. 11 , during a normal operation of executing application processes such as a vehicle control process and a diagnosis process, the microcomputer  33  executes the start determination program, refers to the boot time vector table and the normal time vector table to search for a leading address, and executes a predetermined address of an application program. 
     The microcomputer  33  executes the wireless or wired reprogramming firmware instead of the application program in a rewrite operation of executing a rewrite process on the application program.  FIG. 12  illustrates an operation of rewriting an application program by using difference data as an update program. As illustrated in  FIG. 12 , the microcomputer  33  temporarily saves the application program as old data into the difference engine work area. The microcomputer  33  reads the old data temporarily saved in the difference engine work area, and restores new data from the read old data and the difference data stored in the RAM  33   c  by using a difference engine included in the embedded reprogramming firmware. When the new data is generated from the old data and the difference data, the microcomputer  33  writes the new data to a predetermined address of the memory to rewrite the application program. 
     (A-2) Download Type Single-Bank Memory 
     The download type single-bank memory will be described with reference to  FIGS. 13 and 14 . The download type differs from the embedded type described above in that the wireless reprogramming firmware or the wired reprogramming firmware is downloaded from the outside, the application program is rewritten, and then the wireless reprogramming firmware or the wired reprogramming firmware is deleted. When the application program is updated wirelessly, for example, the wireless reprogramming firmware to be executed in each the ECU  19  is included in the reprogramming data illustrated in  FIG. 6 . The ECU  19  receives wireless reprogramming firmware for use only by the ECU from the CGW  13 , and stores the received wireless reprogramming firmware for use only by the ECU into the RAM. 
     As illustrated in  FIG. 13 , during a normal operation of executing application processes such as a vehicle control process and a diagnosis process, in the same manner as in the embedded type, the microcomputer  33  executes the start determination program, refers to the boot time vector table and the normal time vector table to search for a leading address, and executes a predetermined address of an application program. 
     As illustrated in  FIG. 14 , the microcomputer  33  temporarily saves the application program as old data into the difference engine work area during a rewrite operation of executing a rewrite process on the application program. The microcomputer  33  reads the old data temporarily saved in the difference engine work area, and restores new data from the read old data and the difference data stored in the RAM  33   c  by using difference engine included in the reprogramming firmware downloaded from the outside. When the new data is generated from the old data and the difference data, the microcomputer  33  writes the new data to rewrite the application program. 
     (B) Single-Bank Suspend Memory 
     (B-1) Embedded Type Single-Bank Suspend Memory 
     The embedded type single-bank suspend memory will be described with reference to  FIGS. 15 and 16 . The embedded type single-bank suspend memory has a difference engine work area, an application program area, and a boot program area. Reprogramming firmware for updating a program is located in the boot program area in the same manner as in the single-bank memory, and is not subjected to program update. The application program area that is a program update target has pseudo-bank-A and bank-B, and version information, an application program, and a normal time vector table are located in each of the bank-A and the bank-B. A boot program, reprogramming firmware, a reprogramming time vector table, an active bank determination function, active bank determination information, and a boot time vector table are located in the boot area. 
     As illustrated in  FIG. 15 , during a normal operation of executing application processes such as a vehicle control process and a diagnosis process, the microcomputer  33  executes the boot program to determine which of the bank-A and the bank-B is an active bank on the basis of the active bank determination information of the bank-A and the bank-B according to the active bank determination function. When it is determined that the bank-A is an active bank, the microcomputer  33  refers to the normal time vector table of the bank-A to search for a leading address and executes the application program of the bank-A. Similarly, when it is determined that the bank-B is an active bank, the microcomputer  33  refers to the normal time vector table of the bank-B to search for a leading address and executes the application program of the bank-B. In  FIG. 15 , although the reprogramming firmware is located in the boot program area, the reprogramming firmware may also be subjected to program update and located in each area of the bank-A or the bank-B. 
     As illustrated in  FIG. 16 , during a rewrite operation of executing a rewrite process on an application program of an inactive bank, the microcomputer  33  temporarily saves the application program of the inactive bank as old data into the difference engine work area. The microcomputer  33  reads the old data temporarily saved in the difference engine work area, and restores new data from the read old data and the difference data stored in the RAM  33   c  by using a difference engine in the embedded type reprogramming firmware. When the new data is generated from the old data and the difference data, the microcomputer  33  writes the new data into the inactive bank to rewrite the application program of the inactive bank.  FIG. 16  exemplifies a case where the bank-A is an active bank and the bank-B is an inactive bank. 
     (B-2) Download Type Single-Bank Suspend Memory 
     The download type single-bank suspend memory will be described with reference to  FIGS. 17 and 18 . The download type differs from the embedded type described above in that reprogramming firmware and a reprogramming time vector table are downloaded from the outside, an application program is rewritten, and then the reprogramming firmware and the reprogramming time vector table are deleted. 
     As illustrated in  FIG. 17 , during a normal operation of executing application processes such as a vehicle control process and a diagnosis process, in the same manner as the embedded type, the microcomputer  33  executes the boot program to determine whether the application program is new or old on the basis of the active bank determination information of each of the bank-A and the bank-B according to the active bank determination function, and determines which of the bank-A and the bank-B is an active bank. When it is determined that the bank-A is an active bank, the microcomputer  33  refers to the normal time vector table of the bank-A to search for a leading address and executes the application program of the bank-A. Similarly, when it is determined that the bank-B is an active bank, the microcomputer  33  refers to the normal time vector table of the bank-B to search for a leading address and executes the application program of the bank-B. 
     As illustrated in  FIG. 18 , during a rewrite operation of executing a rewrite process on an application program, the microcomputer  33  temporarily saves the application program of the inactive bank as old data into the difference engine work area. The microcomputer  33  reads the old data temporarily saved in the difference engine work area, and restores new data from the read old data and the difference data stored in the RAM  33   c  by using a difference engine in the reprogramming firmware downloaded from the outside. When the new data is generated from the old data and the difference data, the microcomputer  33  writes the new data to rewrite the application program.  FIG. 18  exemplifies a case where the bank-A is an active bank and the bank-B is an inactive bank. As described above, in the single-bank suspend memory, rewriting of the application program of the bank-B can be executed on the background while executing the application program of the bank-A. 
     (C) Double-Bank Memory 
     (C-1) Embedded Type Double-Bank Memory 
     The embedded type double-bank memory will be described with reference to  FIGS. 19 and 20 . The embedded type single-bank memory includes an application program area and a rewrite program area of the bank-A, an application program area and a rewrite program area of the bank-B, and a boot program area. A boot program is located in the boot area as non-rewritable. The boot program includes a boot swap function and a boot time vector table. Version information, parameter data, an application program, firmware, and a normal time vector table are located in each application program area. A program for controlling rewriting, reprogramming progress management information  2 , reprogramming progress management information  1 , active bank determination information, wireless reprogramming firmware, wired reprogramming firmware, and a boot time vector table are located in each rewrite program area. A boot program, a boot swap function, and a boot time vector table are located in the boot area. 
     As illustrated in  FIG. 19 , during a normal operation of executing application processes such as a vehicle control process and a diagnosis process and during a rewrite operation of executing a rewrite process on an application program of an inactive bank, the microcomputer  33  executes the boot program to determine whether the application program is new or old according to the boot swap function on the basis of each of the active bank determination information of the bank-A and the bank-B, and determines which of the bank-A and the bank-B is an active bank. When it is determined that the bank-A is an active bank, the microcomputer  33  refers to the boot time vector table of the bank-A and the normal time vector table of the bank-A to search for a leading address and executes the application program of the bank-A. Similarly, when it is determined that the bank-B is an active bank, the microcomputer  33  refers to the boot time vector table of the bank-B and the normal time vector table of the bank-B to search for a leading address and executes the application program of the bank-B. 
     As illustrated in  FIG. 20 , during a rewrite operation of executing a rewrite process on an application program of an inactive bank, the microcomputer  33  temporarily saves the application program of the inactive bank as old data into the difference engine work area. The microcomputer  33  reads the old data temporarily saved in the difference engine work area, and restores new data from the read old data and the difference data stored in the RAM  33   c  by using a difference engine in the embedded type reprogramming firmware. When the new data is generated from the old data and the difference data, the microcomputer  33  writes the new data into the inactive bank to rewrite the application program of the inactive bank. Old data temporarily saved in the difference engine work area may be an application program of an active bank or an application program of an inactive bank. In this case, in a case where the application program of the active bank is a target, data of the inactive bank is deleted before writing new data. Here, in a case where reprogramming data acquired from the outside of the vehicle is not difference data but entire data (full data), the acquired reprogramming data is written as new data to the inactive bank.  FIG. 20  exemplifies a case where the bank-A is an active bank and the bank-B is an inactive bank. Old data temporarily saved in the difference engine work area may be an application program of an active bank or an application program of an inactive bank. In a case where it is necessary to match execution addresses of the application programs with each other, the application program of the inactive bank is saved as old data. 
     (C-2) Download Type Double-Bank Memory 
     The download type double-bank memory will be described with reference to  FIGS. 21 and 22 . The download type differs from the embedded type described above in that the wireless reprogramming firmware or the wired reprogramming firmware is downloaded from the outside, the application program is rewritten, and then the wireless reprogramming firmware or the wired reprogramming firmware is deleted. 
     As illustrated in  FIG. 21 , during a normal operation of executing application processes such as a vehicle control process and a diagnosis process and during a rewrite operation of executing a rewrite process on an application program of an inactive bank, in the same manner as in the embedded type, the microcomputer  33  executes the boot program to determine whether the application program is new or old according to the boot swap function on the basis of each of the active bank determination information of the bank-A and the bank-B and to determine which of the bank-A and the bank-B is an active bank, and executes an application program of the active bank to execute an application process. 
     As illustrated in  FIG. 22 , during a rewrite operation of executing a rewrite process on the application program, the microcomputer  33  temporarily saves the application program of the inactive bank as old data in the difference engine work area. The microcomputer  33  reads the old data temporarily saved in the difference engine work area, and restores new data from the read old data and the difference data stored in the RAM  33   c  by using the reprogramming firmware downloaded from the outside. When the new data is generated from the old data and the difference data, the microcomputer  33  writes the new data into the inactive bank to rewrite the application program of the inactive bank. Old data temporarily saved in the difference engine work area may be an application program of an active bank or an application program of an inactive bank. In this case, in a case where the application program of the active bank is a target, data of the inactive bank is deleted before writing new data. Here, in a case where reprogramming data acquired from the outside of the vehicle is not difference data but entire data (full data), the acquired reprogramming data is written as new data to the inactive bank.  FIG. 22  exemplifies a case where the bank-A is an active bank and the bank-B is an inactive bank. Old data temporarily saved in the difference engine work area may be an application program of an active bank or an application program of an inactive bank. As described above, in the double-bank memory, rewriting of the application program of the bank-B can be executed on the background while executing the application program of the bank-A. 
     As described above, in both configurations of the embedded type and the download type, the application program and the rewrite programs for rewriting the application program are located in each application area. In  FIG. 20  and  FIG. 22 , the application program has been described as a reprogramming target, but the rewrite program may also be a reprogramming target. In a case where it is desired that the rewrite program cannot be rewritten, the rewrite program may be located in the boot area. For example, a program for wired rewriting may be located in the boot area such that the wired rewriting using the tool  23  can be reliably performed in a dealer or the like. 
     Next, the overall sequence of rewriting an application program will be described with reference to  FIGS. 23 to 25 . Here, a description will be made of a case where a user operates the mobile terminal  6  as the display terminal  5  to rewrite an application program during parking, but the same applies to a case where the application program is rewritten during parking by operating the in-vehicle display  7 . The distribution package transmitted from the center device  3  to the DCM  12  stores write data of one or more rewrite target ECUs  19 . That is, when there is a single rewrite target ECU  19 , one piece of write data for the single rewrite target ECU  19  is stored in the distribution package, and, when there are a plurality of rewrite target ECUs  19 , a plurality of pieces of write data for the respective a plurality of rewrite target ECUs  19  are stored in the distribution package. Here, there are two rewrite target ECUs  19 , and the two rewrite target ECUs  19  will be referred to as a rewrite target ECU (ID 1 ) and a rewrite target ECU (ID 2 ). The ECUs  19  other than the rewrite target ECU (ID 1 ) and the rewrite target ECU (ID 2 ) will be referred to as other ECUs. 
     Each of the rewrite target ECU (ID 1 ) and the rewrite target ECU (ID 2 ) determines that a transmission condition for a version notification signal is established, for example, when it is determined that a transmission request for the version notification signal has been received from the master device  11 . When the transmission condition for the version notification signal is established, the rewrite target ECU (ID 1 ) transmits the version notification signal including version information of an application program stored therein and an ECU (ID) that can identify the ECU to the master device  11 . When the version notification signal is received from the rewrite target ECU (ID 1 ), the master device  11  transmits the received version notification signal to the center device  3 . Similarly, when the transmission condition for the version notification signal is established, the rewrite target ECU (ID 2 ) transmits the version notification signal including a version of an application program stored therein and an ECU (ID) that can identify the ECU to the master device  11 . When the version notification signal is received from the rewrite target ECU (ID 2 ), the master device  11  transmits the received version notification signal to the center device  3 . 
     When the version notification signals are received from the rewrite target ECU (ID 1 ) and the rewrite target ECU (ID 2 ), the center device  3  specifies the versions of the application programs included in the received version notification signals and the ECUs (ID), and determines availability of write data to be distributed to the rewrite target ECU  19  that is a transmission source of the version notification signal. The center device  3  specifies the version of the current application program of the rewrite target ECU  19  from the version notification signal received from the rewrite target, and collates the version of the current application program with the managed latest version. 
     When the version specified from the version notification signal has the same value as that of the managed latest version, the center device  3  determines that write data to be distributed to the rewrite target ECU  19  that is a transmission source of the version notification signal is unavailable, and the application program stored in the rewrite target ECU  19  does not need to be updated. On the other hand, when the version specified from the version notification signal has a value smaller than that of the managed newest version, the center device  3  determines that write data to be distributed to the rewrite target ECU  19  that is a transmission source of the version notification signal is available, and the application program stored in the rewrite target ECU  19  needs to be updated. 
     When it is determined that the application program stored in the rewrite target ECU  19  needs to be updated, the center device  3  notifies the mobile terminal  6  of information indicating that update is necessary. When the mobile terminal  6  is notified of the information indicating that update is necessary, the mobile terminal displays a distribution feasibility screen (A 1 ). The distribution feasibility screen is the same as a campaign notification screen which will be described later. The user can check the necessity of update from the distribution feasibility screen displayed on the mobile terminal  6 , and can thus select whether or not to perform the update. 
     When the user selects that the update is to be performed on the mobile terminal  6  (A 2 ), the mobile terminal  6  notifies the center device  3  of a download request for a distribution package. When the center device  3  is notified of the download request for the distribution package from the mobile terminal  6 , the center device transmits the distribution package to the master device  11 . 
     When the master device  11  downloads the distribution package from the center device  3 , the master device initiates a package authentication process on the downloaded distribution package (B 1 ). When the master device  11  authenticates the distribution package and completes the package authentication process, the master device initiates a write data extraction process (B 2 ). When the master device  11  extracts the write data from the distribution package, and completes the write data extraction process, the master device transmits a download completion notification signal to the center device  3 . 
     When the center device  3  receives the download completion notification signal from the master device  11 , the center device  3  notifies the mobile terminal  6  of completion of the download. When the mobile terminal  6  is notified of completion of the download from the center device  3 , the mobile terminal  6  displays a download completion notification screen (A 3 ). The user can check that the download has been completed from the download completion notification screen displayed on the mobile terminal  6 , and can thus set a rewrite initiation time of an application program on the vehicle side. 
     When the user sets the rewrite initiation time of the application program on the vehicle side on the mobile terminal  6  (A 4 ), the mobile terminal  6  notifies the center device  3  of the rewrite initiation time. When the center device  3  is notified of the rewrite initiation time from the mobile terminal  6 , the center device  3  stores the rewrite initiation time set by the user as a set initiation time. When the current time reaches the set initiation time (A 5 ), the center device  3  transmits a rewrite instruction signal to the master device  11 . 
     When the rewrite instruction signal is received from the center device  3 , the master device  11  transmits a power supply start request to the power supply management ECU  20 , and thus causes the rewrite target ECU (ID 1 ), the rewrite target ECU (ID 2 ), and the other ECUs to transition from a stop state or a sleep state to an active state (X 1 ). 
     The master device  11  initiates to distribute the write data to the rewrite target ECU (ID 1 ) and instructs the rewrite target ECU (ID 1 ) to write the write data. The rewrite target ECU (ID 1 ) initiates to receive the write data from the master device  11 , and initiates to write the write data and initiates a program rewrite process when the write data is instructed to be written (C 1 ). When the rewrite target ECU (ID 1 ) completes reception of the write data from the master device  11 , completes writing of the write data, and completes the program rewrite process, the rewrite target ECU (ID 1 ) transmits a rewrite completion notification signal to the master device  11 . 
     When the rewrite completion notification signal is received from the rewrite target ECU (ID 1 ), the master device  11  initiates to distribute the write data to the rewrite target ECU (ID 2 ), and instructs the rewrite target ECU (ID 2 ) to write the write data. The rewrite target ECU (ID 2 ) initiates to receive the write data from the master device  11 , and initiates to write the write data and initiates a program rewrite process when the write data is instructed to be written (D 1 ). When the rewrite target ECU (ID 2 ) completes reception of the write data from the master device  11 , completes writing of the write data, and completes the program rewrite process, the rewrite target ECU (ID 2 ) transmits a rewrite completion notification signal to the master device  11 . When the rewrite completion notification signal is received from the rewrite target ECU (ID 2 ), the master device  11  transmits the rewrite completion notification signal to the center device  3 . 
     When the rewrite completion notification signal is received from the master device  11 , the center device  3  notifies the mobile terminal  6  of the completion of rewriting of the application program. When the mobile terminal  6  is notified of the completion of rewriting of the application program from the center device  3 , the mobile terminal  6  displays a rewrite completion notification screen (A 6 ). The user can check that rewriting of the application program has been completed from the rewrite completion notification screen displayed on the mobile terminal  6 , and can thus set execution of synchronization as activation. 
     When the user sets the execution of synchronization on the mobile terminal  6  (A 7 ), that is, when the user sets an approval for activation of a new program, the mobile terminal  6  notifies the center device  3  of the execution of synchronization. When the center device  3  is notified of the execution of synchronization from the mobile terminal  6 , the center device transmits a synchronization switching instruction signal to the master device  11 . When the synchronization switching instruction signal is received from the center device  3 , the master device  11  distributes the received synchronization switching instruction signal to the rewrite target ECU (ID 1 ) and the rewrite target ECU (ID 2 ). 
     When the synchronization switching instruction signal is received from the master device  11 , each of the rewrite target ECU (ID 1 ) and the rewrite target ECU (ID 2 ) initiates a program switching process of switching an application program to be started next time from the old application program to the new application program (C 2  and D 2 ). When the program switching process has been completed, each of the rewrite target ECU (ID 1 ) and the rewrite target ECU (ID 2 ) transmits a switching completion notification signal to the master device  11 . 
     When the switching completion notification signal is received from the rewrite target ECU (ID 1 ) and the rewrite target ECU (ID 2 ), the master device  11  distributes a version read signal to the rewrite target ECU (ID 1 ) and the rewrite target ECU (ID 2 ). When the version read signal is received from the master device  11 , each of the rewrite target ECU (ID 1 ) and the rewrite target ECU (ID 2 ) reads a version of an application program to be operated thereafter (C 3  and D 3 ), and transmits a latest version notification signal including the read version to the master device  11 . The master device  11  checks a version of software or performs rollback as necessary by receiving the version notification signal from the rewrite target ECU (ID 1 ) and the rewrite target ECU (ID 2 ). 
     When the version notification signal is received from the rewrite target ECU (ID 1 ) and the rewrite target ECU (ID 2 ), the master device  11  transmits a power supply stop request to the power supply management ECU  20 , and thus causes the rewrite target ECU (ID 1 ), the rewrite target ECU (ID 2 ), and the other ECUs to transition from the active state to the stop state or the sleep state (X 2 ). 
     The master device  11  transmits the latest version notification signal to the center device  3 . When the latest version notification signal is received from the master device  11 , the center device  3  specifies the latest versions of the application programs of the rewrite target ECU (ID 1 ) and the rewrite target ECU (ID 2 ) from the received latest version notification signal, and notifies the mobile terminal  6  of the specified latest versions. When a notification of the latest versions is sent from the center device  3 , the mobile terminal  6  displays a latest version notification screen indicating the latest versions of which the notification is sent on the mobile terminal  6  (A 8 ). The user can check the latest versions from the latest version notification screen displayed on the mobile terminal  6 , and can thus check that the activation has been completed. 
     Next, with reference to  FIGS. 26 to 29 , a description will be made of timing charts for operations of the DCM  12 , the CGW  13  and the rewrite target ECU  19  when an application program is rewritten. Here, a description will be made of a case where an application program of the double-bank memory ECU is rewritten during a period in which the IG switch  42  is turned on by a user operation, that is, while the vehicle can travel, and application programs of the single-bank suspend memory ECU and the single-bank memory ECU are rewritten during parking after the IG switch  42  is turned off by the user operation. A description will be made of a case where the application program is rewritten by using power supply control and a case where the application program is rewritten by using self-retention power. 
     (a) Case where Application Program is Rewritten by Using Power Supply Control 
     The case where the application program is rewritten by using power supply control will be described with reference to  FIGS. 26 and 27 . The rewriting of the application program by using power supply control indicates a configuration in which a rewrite operation is controlled in accordance with switching of a power supply without using the self-retention power circuit. When the user switches on the IG switch in an OFF state and thus the vehicle power switches from the +B power to the IG power, each of the DCM  12 , the CGW  13 , the double-bank memory ECU, the single-bank suspend memory ECU, and the single-bank memory ECU initiates a normal operation (t 1 ). 
     When a notification of download initiation is sent from the center device  3 , the DCM  12  transitions from the normal operation to a download operation, and initiates to download a distribution package from the center device  3  (t 2 ). The DCM  12  may download the distribution package on the background while performing the normal operation. When the download of the distribution package from the center device  3  has been completed, the DCM  12  returns from the download operation to the normal operation (t 3 ). 
     When a notification of a rewrite instruction signal (installation instruction signal) is sent from the center device  3  or the CGW  13 , the DCM  12  transitions from the normal operation to a data transfer/center communication operation, and initiates the data transfer/center communication operation (t 4 ). That is, the DCM  12  extracts write data from the distribution package, initiates to transfer the write data to the CGW  13 , acquires a rewrite progress situation from the CGW  13 , and initiates to notify the center device  3  of the rewrite progress situation. 
     When acquisition of the write data from the DCM  12  is initiated, the CGW  13  transitions from the normal operation to a reprogramming master operation, initiates the reprogramming master operation, initiates to distribute the write data to the double-bank memory ECU, and instructs the double-bank memory ECU to write the write data. When the double-bank memory ECU initiates to receive write data from the CGW  13 , the double-bank memory ECU initiates a programming phase (hereinafter, also referred to as an installation phase) in a normal operation. That is, the double-bank memory ECU performs the installation of the application program on the background while performing the normal operation. The double-bank memory ECU initiates to write the received write data into the flash memory and initiates to rewrite the application program. 
     When the user switches off the IG switch in an ON state such that the vehicle power switches from the IG power to the +B power during rewriting of the application program in the double-bank memory ECU, the DCM  12  stops the data transfer/center communication operation, the CGW  13  stops the reprogramming master operation, and the double-bank memory ECU stops the installation phase and stops rewriting of the application program (t 5 ). 
     Thereafter, when the user switches on the IG switch in an OFF state such that the vehicle power switches from the +B power to the IG power, the DCM  12  resumes the data transfer/center communication operation, the CGW  13  resumes the reprogramming master operation, and the double-bank memory ECU resumes the installation phase and resumes rewriting of the application program (t 6 ). That is, the user switches off the IG switch in an ON state such that the vehicle power switches from the IG power to +B power, and then the user switches on the IG switch in an OFF state such that the vehicle power switches from the +B power to the IG power, and, each time a trip occurs, the double-bank memory ECU repeats stopping and resuming of rewriting of the application program (t 7  and t 8 ). 
     When the double-bank memory ECU completes writing of the write data, and completes rewriting of the application program, the double-bank memory ECU finishes the installation phase, and transitions from the normal operation to activation standby. That is, the double-bank memory ECU is not started on the new bank (bank-B) in which the application program is rewritten at the time point when the activation phase is not performed, and remains started on the old bank (bank-A) (t 9 ). 
     After the user switches off the IG switch in an ON state such that the vehicle power switches from the IG power to the +B power (t 10 ), when the double-bank memory ECU completes rewriting of the application program at that time, the CGW  13  transmits a power supply start request to the power supply management ECU  20 . When the vehicle power switches from the +B power to the IG power by the CGW  13  transmitting the power supply start request to the power supply management ECU  20 , the DCM  12  resumes the data transfer/center communication operation, and the CGW  13  resumes the reprogramming master operation, and initiates to distribute the write data to the single-bank suspend memory ECU and the single-bank memory ECU. When reception of the write data from the CGW  13  is initiated, the single-bank suspend memory ECU and the single-bank memory ECU transition from the normal operation to a boot process and initiate the installation phase in the boot process (t 11 ). That is, the single-bank suspend memory ECU and the single-bank memory ECU do not perform installation in parallel to the normal operation, and perform installation in the boot process in which the application program is not operated. 
     When rewriting of the application program is initiated, the single-bank suspend memory ECU stops rewriting of the application program in a case where the IG switch  42  switches from an OFF state to an ON state due to the user operation before rewriting of the application program is completed. The single-bank suspend memory ECU returns to an active bank (bank-A) as a start bank instead of an inactive bank (bank-B) in which rewriting of the application program is stopped. When rewriting of the application program is initiated, the single-bank memory ECU continues rewriting of the application program even though the IG switch  42  switches from an OFF state to an ON state due to the user operation before rewriting of the application program is completed. This is because the single-bank memory ECU cannot return to the normal operation if rewriting of the application program is stopped halfway. Preferably, after rewriting of the application program of the single-bank memory ECU is initiated, it is desirable to disable the user operation on the IG switch  42  until rewriting of the application program is completed. 
     When the single-bank suspend memory ECU completes writing of the write data and completes rewriting of the application program, the single-bank suspend memory ECU finishes the installation phase in the boot process and transitions from the boot process to activation standby. That is, the single-bank suspend memory ECU is not started on the new bank (bank-B) in which the application program is rewritten at the time point when the activation phase is not performed, and remains started on the old bank (bank-A). When the single-bank memory ECU completes writing of the write data and completes rewriting of the application program, the single-bank memory ECU finishes the installation phase in the boot process and waits for activation (t 12 ). 
     When the power supply management ECU  20  switches the vehicle power from the IG power to the +B power in response to an activation instruction from the CGW  13 , each of the double-bank memory ECU and the single-bank suspend memory ECU switches from the old bank to the new bank to be started in the new bank, and initiates a post-programming phase (hereinafter, also referred to as an activation phase) in the new bank start. The single-bank memory ECU initiates restart, and initiates the activation phase in restart after installation is completed (t 13  and t 14 ). In the activation, for example, it is checked that accurate start is performed by the new program, or the CGW  13  is notified of version information. 
     When the activation has been completed, and the power supply management ECU  20  switches the vehicle power from the IG power to the +B power in response to an activation completion instruction from the CGW  13 , the DCM  12  transitions from the data transfer/center communication operation to a sleep/stop operation and initiates the sleep/stop operation. The CGW  13  transitions from the reprogramming master operation to the sleep/stop operation and initiates the sleep/stop operation. Each of the double-bank memory ECU, single-bank suspend memory ECU, and single-bank memory ECU transitions from the new bank start to the sleep/stop operation (t 15 ). 
     Thereafter, when the user switches on the IG switch in an OFF state such that the vehicle power switches from the +B power to the IG power, each of the double-bank memory ECU and the single-bank suspend memory ECU starts the new application program with the new bank (bank-B) as an active bank, and the single-bank memory ECU starts the new application program (t 16 ). 
     (b) Case where Application Program is Rewritten by Using Self-Retention Power 
     The case where an application program is rewritten by using self-retention power will be described with reference to  FIGS. 28 and 29 . Rewriting of the application program using the self-retention power indicates a configuration in which a rewrite operation is controlled by using the self-retention power circuit. When the user switches on the IG switch in an OFF state such that the vehicle power switches from the +B power to the IG power, each of the DCM  12 , the CGW  13 , the double-bank memory ECU, the single-bank suspend memory ECU, and the single-bank memory ECU initiates a normal operation (t 21 ). 
     When a notification of initiation of download is sent from the center device  3 , that is, when a notification that update is available due to a new program is sent, the DCM  12  transitions from the normal operation to a download operation, and initiates to download a distribution package from the center device  3  (t 22 ). When the download of the distribution package from the center device  3  has been completed, the DCM  12  returns from the download operation to the normal operation (t 23 ). 
     When a notification of a rewrite instruction signal (installation instruction signal) is sent from the center device  3  or the CGW  13 , the DCM  12  transitions from the normal operation to a data transfer/center communication operation, and initiates the data transfer/center communication operation (t 24 ). That is, the DCM  12  extracts write data from the distribution package, initiates to transfer the write data to the CGW  13 , acquires a rewrite progress situation from the CGW  13 , and initiates to notify the center device  3  of the rewrite progress situation. 
     When acquisition of the write data from the DCM  12  is initiated, the CGW  13  transitions from the normal operation to a reprogramming master operation, initiates the reprogramming master operation, initiates to distribute the write data to the double-bank memory ECU, and instructs the double-bank memory ECU to write the write data. When the double-bank memory ECU initiates to receive write data from the CGW  13 , the double-bank memory ECU initiates a programming phase (hereinafter, also referred to as an installation phase) in a normal operation. That is, the double-bank memory ECU performs the installation of the application program on the background while performing the normal operation. The double-bank memory ECU initiates to write the received write data into the flash memory and initiates to rewrite the application program. 
     When the user switches off the IG switch in an ON state such that the vehicle power switches from the IG power to the +B power during rewriting of the application program in the double-bank memory ECU (t 25 ), the DCM  12  continues the data transfer/center communication operation, the CGW  13  continues the reprogramming master operation, and the double-bank memory ECU continues the installation phase and continues rewriting of the application program immediately after the vehicle power switches from the IG power to the +B power. When a self-retention period that is a preset period elapses after the vehicle power switches from the IG power to the +B power, the DCM  12  stops the data transfer/center communication operation, the CGW  13  stops the reprogramming master operation, and the double-bank memory ECU stops the installation phase and stops rewriting of the application program (t 26 ). That is, the installation is continued by supplying power from the vehicle battery  40  until a predetermined time elapses after the IG switch  42  is turned off. 
     Thereafter, when the user switches on the IG switch in an OFF state such that the vehicle power switches from the +B power to the IG power, the DCM  12  resumes the data transfer/center communication operation, the CGW  13  resumes the reprogramming master operation, and the double-bank memory ECU resumes the installation phase and resumes rewriting of the application program (t 27 ). That is, the user switches off IG switch in an ON state such that the vehicle power switches from IG power to +B power, and then the user switches on the IG switch in an OFF state such that the vehicle power switches from +B power to IG power, and, each time a trip occurs, the double-bank memory ECU repeats stopping and resuming of rewriting of the application program (t 28  to t 30 ). However, until the self-retention period elapses after the vehicle power switches from the IG power to the +B power, the DCM  12  continues the data transfer/center communication operation, the CGW  13  continues the reprogramming master operation, and the double-bank memory ECU continues the installation phase and continues rewriting of the application program. 
     When the double-bank memory ECU completes writing of the write data, and completes rewriting of the application program, the double-bank memory ECU finishes the installation phase, and transitions from the normal operation to activation standby. That is, the double-bank memory ECU is not started on the new bank (bank-B) in which the application program is rewritten at the time point when the activation phase is not performed, and remains started on the old bank (bank-A) (t 31 ). 
     When the user switches off the IG switch in an ON state such that the vehicle power from the IG power to the +B power and rewriting of the application program is completed at that time in the double-bank memory ECU at that time, each of the single-bank suspend memory ECU and the single-bank memory ECU transitions from the normal operation to a boot process, initiates the boot process, and initiates the installation phase in the boot process (t 32 ). 
     When the single-bank suspend memory ECU and the single-bank memory ECU complete writing of the write data, and complete rewriting of the application program, the single-bank suspend memory ECU and the single-bank memory ECU finish the installation phase in the boot process (t 33 ). When the vehicle power switches from the +B power to the IG power by the CGW  13  transmitting the power supply start request to the power supply management ECU  20 , the DCM  12  resumes the data transfer/center communication operation (t 34 ). 
     When the single-bank suspend memory ECU completes writing of the write data and completes rewriting of the application program, the single-bank suspend memory ECU transitions from the boot process to activation standby. That is, the single-bank suspend memory ECU is not started on the new bank (bank-B) in which the application program is rewritten at the time point when the activation phase is not performed, and remains started on the old bank (bank-A). When the single-bank memory ECU completes writing of the write data and completes rewriting of the application program, the single-bank memory ECU finishes the installation phase in the boot process and waits for activation (t 35 ). 
     When the power supply management ECU  20  switches the vehicle power from the IG power to the +B power in response to an activation instruction from the CGW  13 , each of the double-bank memory ECU and the single-bank suspend memory ECU switches from the old bank to the new bank to be started on the new bank, and initiates an activation phase in the new bank start. The single-bank memory ECU initiates restart, and initiates the activation phase in restart after installation is completed (t 36  and t 37 ). 
     When the activation has been completed, and the power supply management ECU  20  switches the vehicle power from the IG power to the +B power in response to an activation completion instruction from the CGW  13 , the DCM  12  transitions from the data transfer/center communication operation to a sleep/stop operation and initiates the sleep/stop operation. The CGW  13  transitions from the reprogramming master operation to the sleep/stop operation and initiates the sleep/stop operation. Each of the double-bank memory ECU, single-bank suspend memory ECU, and single-bank memory ECU transitions from the new bank start to the sleep/stop operation (t 38 ). 
     Thereafter, when the user switches on the IG switch in an OFF state such that the vehicle power switches from the +B power to the IG power, each of the double-bank memory ECU and the single-bank suspend memory ECU starts the new application program with the new bank (bank-B) as an active bank, and the single-bank memory ECU starts the new application program (t 39 ). 
     Prior to download of a distribution package from the center device  3  and distribution of write data to the rewrite target ECU  19 , the CGW  13  performs the following checking. Prior to download of a distribution package from the center device  3 , the CGW  13  checks a radio wave environment, a remaining battery charge of the vehicle battery  40 , and a memory capacity of the DCM  12  such that the distribution package can be downloaded normally. Prior to distribution of write data to the rewrite target ECU  19 , the CGW  13  performs detection of an intrusion sensor, detection of a door lock, detection of a curtain, and detection of IG-off as a check of a manned environment in order not to make an installation environment unstable such that write data can be distributed normally, and checks a version and the occurrence of abnormality as a check of whether or not the rewrite target ECU  19  can be written. The CGW  13  performs a falsification check, access authentication, a version check, and the like as a check of write data to be distributed to the rewrite target ECU  19  prior to initiation of installation, performs a communication disruption check, an error occurrence check, and the like during the installation, and performs a version check, an integrity check, a diagnostic trouble code (DTC, error code) check, and the like after the installation is completed. 
     Next, a screen displayed on the display terminal  5  will be described with reference to  FIGS. 30 to 46 . As illustrated in  FIG. 30 , in a configuration in which an application program of the rewrite target ECU  19  is rewritten through OTA, there are phases of a campaign notification, download, installation, and activation. The campaign notification is a notification of program update. For example, the campaign notification is that the master device  11  downloads distribution specification data or the like in response to a determination that update of an application program is available in the center device  3 . The display terminal  5  displays a screen in each phase as rewriting of the application program progresses. Here, a screen displayed on the in-vehicle display  7  will be described. 
     As illustrated in  FIG. 31 , the CGW  13  displays a navigation screen  501  such as a well-known route guidance screen, which is one of the navigation functions, on the in-vehicle display  7  at a normal time prior to a campaign notification. When the campaign notification occurs in this state, the CGW  13  displays a campaign notification icon  501   a  indicating the occurrence of the campaign notification on the lower right of the navigation screen  501 , as illustrated in  FIG. 32 . The user can recognize the occurrence of the campaign notification regarding the update of the application program by checking the display of the campaign notification icon  501   a.    
     When the user operates the campaign notification icon  501   a  in this state, as illustrated in  FIG. 33 , the CGW  13  displays a campaign notification screen  502  in a pop-up form on the navigation screen  501 . The CGW  13  is not limited to displaying the campaign notification screen  502  in a pop-up form, and may employ other display aspects. On the campaign notification screen  502 , the CGW  13  displays, for example, a guidance such as “software update is available” to notify the user of the occurrence of the campaign notification, and displays a “check” button  502   a  and a “later” button  502   b  to wait for the user operation. In this case, the user may proceed to the next screen for initiating rewriting of the application program by operating the “check” button  502   a . When the user operates the “later” button  502   b , the CGW  13  deletes the pop-up display of the campaign notification screen  502 , and returns the screen to the screen displaying the campaign notification icon  501   a  illustrated in  FIG. 32 . 
     When the user operates the “check” button  502   a  in this state, as illustrated in  FIG. 34 , the CGW  13  switches the display from the navigation screen  501  to a download approval screen  503 , and displays the download approval screen  503  on the in-vehicle display  7 . In the download approval screen  503 , the CGW  13  notifies the user of a campaign ID or the name of the update, displays a “download initiation” button  503   a , a “details check” button  503   b , and a “back” button  503   c , and waits for the user operation. In this case, the user may initiate download by operating the “download initiation” button  503   a , display details of the download by operating the “details check” button  503   b , and reject the download and return to the previous screen by displaying the “back” button  503   c . In the case where the “back” button  503   c  is operated, the user may proceed to a screen for initiating the download by operating the campaign notification icon  501   a.    
     When the user operates the “details check” button  503   b  in a state in which the download approval screen  503  is displayed, as illustrated in  FIG. 35 , the CGW  13  performs switching of display contents of the download approval screen  503  and displays the details of the download on the in-vehicle display  7 . The CGW  13  displays a content of the update, the time required for the update, restrictions on vehicle functions due to the update, and the like by using the received distribution specification data as the details of the download. When the user operates the “download initiation” button  503   a , the CGW  13  initiates to download a distribution package via the DCM  12 . In parallel to initiation of the download of the distribution package, as illustrated in  FIG. 36 , the CGW  13  switches the display from the download approval screen  503  to the navigation screen  501 , displays the navigation screen  501  on the in-vehicle display  7  again, and displays a download-in-progress icon  501   b  indicating that the download is in progress on the lower right of the navigation screen  501 . The user can recognize that the download of the distribution package is in progress by checking the display of the download-in-progress icon  501   b.    
     When the user operates the download-in-progress icon  501   b  in this state, as illustrated in  FIG. 37 , the CGW  13  switches the display from the navigation screen  501  to a download-in-progress screen  504 , and displays the download-in-progress screen  504  on the in-vehicle display  7 . The CGW  13  notifies the user that the download is in progress, displays a “details check” button  504   a , a “back” button  504   b , and a “cancel” button  504   c  on the download-in-progress screen  504 , and waits for the user operation. In this case, the user can display details during download by operating the “details check” button  504   a , and can stop the download by operating the “cancel” button  504   c.    
     When the download has been completed, the CGW  13  displays a download completion notification screen  505  in a pop-up form on the navigation screen  501  as illustrated in  FIG. 38 . On the download completion notification screen  505 , for example, the CGW  13  displays a guidance such as “downloaded software is updatable” to notify the user of the completion of the download, displays a “check” button  505   a  and a “later” button  505   b , and waits for the user operation. In this case, the user may proceed to a screen for initiating installation by operating the “check” button  505   a.    
     When the user operates the “check” button  505   a  in this state, as illustrated in  FIG. 39 , the CGW  13  switches the display from the navigation screen  501  to an installation approval screen  506 , and displays the installation approval screen  506  on the in-vehicle display  7 . On the installation approval screen  506 , the CGW  13  notifies the user of the time required for installation, or restrictions and setting of schedules, displays an “immediate update” button  506   a , an “update reservation” button  506   b , and a “back” button  506   c , and waits for the user operation. In this case, the user may immediately initiate the installation by operating the “immediate update” button  506   a . The user may also reserve and initiate the installation by setting the time at which the installation is to be performed and operating the “update reservation” button  506   b . The user may reject the installation and return to the previous screen by operating the “back” button  506   c . In a case where the “back” button  506   c  is operated, the user may proceed to a screen for initiating the installation by operating the download-in-progress icon  501   b.    
     When the user operates the “immediate update” button  506   a  in this state, as illustrated in  FIG. 40 , the CGW  13  performs switching of display contents of the installation approval screen  506 , and displays details of the installation on the in-vehicle display  7 . The CGW  13  receives an installation request on the installation approval screen  506  and notifies the user that the installation is to be initiated. 
     When the installation is initiated, as illustrated in  FIG. 41 , the CGW  13  switches the display from the installation approval screen  506  to the navigation screen  501 , displays the navigation screen  501  on the in-vehicle display  7  again, and displays an installation-in-progress icon  501   c  indicating that the installation is in progress on the lower right of the navigation screen  501 . The user can recognize that the installation is in progress by checking the display of the installation-in-progress icon  501   c.    
     When the user operates the installation-in-progress icon  501   c  in this state, as illustrated in  FIG. 42 , the CGW  13  switches the display from the navigation screen  501  to an installation-in-progress screen  507 , and displays the installation-in-progress screen  507  on the in-vehicle display  7 . The CGW  13  notifies the user that the installation is in progress on the installation-in-progress screen  507 . The CGW  13  may, for example, cause the installation-in-progress screen  507  to show the time-remaining or percentage-of-progress of the installation. 
     When the installation has been completed, as illustrated in  FIG. 43 , the CGW  13  switches the display from the navigation screen  501  to an activation approval screen  508 , and displays the activation approval screen  508  on the in-vehicle display  7 . On the activation approval screen  508 , the CGW  13  notifies the user of a content of the activation and displays a “back” button  508   a  and an “OK” button  508   b  to wait for the user operation. In this case, the user may reject the activation and return to the previous screen by operating the “back” button  508   a . The user may approve the activation by operating the “OK” button  508   b . In a case where the “back” button  508   a  is operated, the user may proceed to a screen for executing the activation by operating the installation-in-progress icon  501   c . Such display or approval may be omitted without being displayed by the user&#39;s settings or scenes of the program. 
     When the user turns on the IG power in the state after the user operates the “OK” button  508   b , as illustrated in  FIG. 44 , the CGW  13  displays an activation completion notification screen  509  in a pop-up form on the navigation screen  501 . On the activation completion notification screen  509 , the CGW  13  displays, for example, a guidance such as “software update has been completed” to notify the user of the completion of the activation, displays an “OK” button  509   a  and a “details check” button  509   b , and waits for the user operation. In this case, the user may delete the pop-up display on the activation completion notification screen  509  by operating the “OK” button  509   a , and may display details of the completion of the activation by operating the “details check” button  509   b.    
     When the user operates the “OK” button  509   a  in this state, as illustrated in  FIG. 45 , the CGW  13  switches the display from the navigation screen  501  to a check operation screen  510 , and displays the check operation screen  510  on the in-vehicle display  7 . On the check operation screen  510 , the CGW  13  notifies the user of the completion of the activation, displays a “details check” button  510   a  and an “OK” button  510   b , and waits for the user operation. In this case, the user may display details of the completion of the activation by operating the “details check” button  510   a.    
     When the user operates the “details check” button  510   a  in this state, as illustrated in  FIG. 46 , the CGW  13  performs switching of display contents of the check operation screen  510 , and displays details of the completion of the activation on the in-vehicle display  7 . The CGW  13  displays a function added or changed due to the update as update details, and displays the “OK” button  510   b . When the user operates the “OK” buttons  509   a  and  510   b , the CGW  13  determines that the user has confirmed the software update completion. 
     As described above, the vehicle-side system  4  controls the respective operation phases such as the campaign notification, the download, the installation, the activation, and the update completion, and presents display corresponding to each operation phase to the user. In the above description, the CGW  13  is configured to control the display, but the in-vehicle display  7  may be configured to receive an operation phase or distribution specification data from the CGW  13  and to perform the display. 
     Next, characteristic processes performed by the vehicle program rewriting system  1  will be described with reference to  FIGS. 47 to 233 . The vehicle program rewriting system  1  performs the following characteristic processes. 
     (1) Distribution package transmission determination process 
     (2) Distribution package download determination process 
     (3) Write data transfer determination process 
     (4) Write data acquisition determination process 
     (5) Installation instruction determination process 
     (6) Security access key management process 
     (7) Write data verification process 
     (8) Data storage bank information transmission control process 
     (9) Non-rewrite target power supply management process 
     (10) File transfer control process 
     (11) Write data distribution control process 
     (12) Activation request instruction process 
     (13) Activation execution control process 
     (14) Rewrite target group management process 
     (15) Rollback execution control process 
     (16) Rewrite progress situation display control process 
     (17) Difference data consistency determination process 
     (18) Rewrite execution control process 
     (19) Session establishment process 
     (20) Retry point specifying process 
     (21) Progress state synchronization control process 
     (22) Display control information transmission control process 
     (23) Display control information reception control process 
     (24) Screen display control process for progress display 
     (25) Program update notification control process 
     (26) Self-retention power execution control process 
     Each of the center device  3 , the DCM  12 , the CGW  13 , the ECU  19 , and the in-vehicle display  7  has the following functional blocks as configurations for performing the characteristic processes (1) to (26) described above. 
     As illustrated in  FIG. 47 , the center device  3  includes a distribution package transmission unit  51 . When a download request for a distribution package is received from the DCM  12 , the distribution package transmission unit  51  transmits the distribution package to the DCM  12 . In addition to the above-described configuration, the center device  3  includes a distribution package transmission determination unit  52 , a progress state synchronization control unit  53 , a display control information transmission control unit  54 , and a write data selection unit  55  (corresponding to an update data selection unit) as a configuration of performing the characteristic processes. When data storage bank information is received from the master device  11 , the write data selection unit  55  (corresponding to an update data selection unit) selects write data compliant to an inactive bank on the basis of a software version and an active bank specified by the received data storage bank information. That is, the distribution package transmission unit  51  transmits the distribution package including the write data selected by the write data selection unit  55  to the DCM  12 . The functional blocks performing the characteristic processes will be described later. 
     As illustrated in  FIG. 48 , the DCM  12  includes a download request transmission unit  61 , a distribution package download unit  62 , a write data extraction unit  63 , a write data transfer unit  64 , a rewrite specification data extraction unit  65 , and a rewrite specification data transfer unit  66 . The download request transmission unit  61  transmits a download request for a distribution package to the center device  3 . The distribution package download unit  62  downloads the distribution package from the center device  3 . When the distribution package is downloaded from the center device  3  by the distribution package download unit  62 , the write data extraction unit  63  extracts write data from the downloaded distribution package. 
     When the write data is extracted from the distribution package by the write data extraction unit  63 , the write data transfer unit  64  transfers the extracted write data to the CGW  13 . When the distribution package is downloaded from the center device  3  by the distribution package download unit  62 , the rewrite specification data extraction unit  65  extracts rewrite specification data from the downloaded distribution package. When rewrite specification data is extracted from the distribution package by the rewrite specification data extraction unit  56 , the rewrite specification data transfer unit  66  transfers the extracted rewrite specification data to the CGW  13 . In addition to the above-described configuration, the DCM  12  includes a distribution package download determination unit  67  and a write data transfer determination unit  68  as a configuration of performing the characteristic processes. The functional blocks performing the characteristic processes will be described later. 
     As illustrated in  FIGS. 49 and 50 , the CGW  13  includes an acquisition request transmission unit  71 , a write data acquisition unit  72  (corresponding to an update data storage unit), a write data distribution unit  73  (corresponding to an update data distribution unit), a rewrite specification data acquisition unit  74 , and a rewrite specification data analysis unit  75 . The write data acquisition unit  72  acquires write data from the DCM  12  due to transfer of the write data from the DCM  12 . In a case where the write data is acquired by the write data acquisition unit  72 , the write data distribution unit  73  distributes the acquired write data to the rewrite target ECU  19  when the distribution timing of the write data is reached. The rewrite specification data acquisition unit  74  acquires rewrite specification data from the DCM  12  due to transfer of the rewrite specification data from the DCM  12 . When the rewrite specification data is acquired by the rewrite specification data acquisition unit  74 , the rewrite specification data analysis unit  75  analyzes the acquired rewrite specification data. 
     In addition to the above-described configuration, the CGW  13  includes, as a configuration of performing the characteristic processes, a write data acquisition determination unit  76 , an installation instruction determination unit  77 , a security access key management unit  78 , a write data verification unit  79 , a data storage bank information transmission control unit  80 , a non-rewrite target power supply management unit  81 , a file transfer control unit  82 , a write data distribution control unit  83 , an activation request instruction unit  84 , a rewrite target group management unit  85 , a rollback execution control unit  86 , a rewrite progress situation display control unit  87 , a progress state synchronization control unit  88 , a display control information reception control unit  89 , a progress display screen display control unit  90 , a program update notification control unit  91 , and a self-retention power execution control unit  92 . The functional blocks performing the characteristic processes will be described later. 
     As illustrated in  FIG. 51 , the ECU  19  includes a write data receiving unit  101  and a program rewriting unit  102 . The write data receiving unit  101  receives write data from the CGW  13 . When the write data is received from the CGW  13  by the write data receiving unit  101 , the program rewriting unit  102  writes the received write data into a flash memory and thus rewrites an application program. In addition to the above-described configuration, the ECU  19  includes a difference data consistency determination unit  103 , a rewrite execution control unit  104 , a session establishment unit  105 , a retry point specifying unit  106 , an activation execution control unit  107 , and a self-retention power execution control unit  108  as a configuration of performing the characteristic processes. The functional blocks performing the characteristic processes will be described later. 
     As illustrated in  FIG. 52 , the in-vehicle display  7  includes a distribution specification data reception control unit  111 . The distribution specification data reception control unit  111  controls reception of distribution specification data. 
     Hereinafter, each of the processes (1) to (26) described above will be described in order. 
     (1) Distribution Package Transmission Determination Process and (2) Distribution Package Download Determination Process 
     The distribution package transmission determination process in the center device  3  will be described with reference to  FIGS. 53 and 54 , and the distribution package download determination process in the master device  11  will be described with reference to  FIGS. 55 and 56 . 
     As illustrated in  FIG. 53 , the center device  3  includes a software information acquisition unit  52   a , an update availability determination unit  52   b , an update propriety determination unit  52   c , and a campaign information transmission unit  52   d  in the distribution package transmission determination unit  52 . The software information acquisition unit  52   a  acquires software information of each ECU  19  from the vehicle side. Specifically, the software information acquisition unit  52   a  acquires ECU configuration information including software information such as a version and a write bank and hardware information from the vehicle side. The software information acquisition unit  52   a  may acquire vehicle condition information such as a trouble code, setting of an anti-theft alarm function, and license contract information from the vehicle side in combination with the ECU configuration information. 
     When the software information is acquired by the software information acquisition unit  52   a , the update availability determination unit  52   b  determines whether or not availability of update data for the vehicle on the basis of the acquired software information. That is, the update availability determination unit  52   b  compares a version of the acquired software information with a version of the latest software information managed by the update availability determination unit  52   b , to determine whether both of the versions match each other, and thus determines availability of update data for the vehicle. The update availability determination unit  52   b  determines that there is no update data for the vehicle when it is determined that both of the versions match each other, and determines that update data for the vehicle is available when it is determined that both of the versions do not match each other. 
     When it is determined by the update availability determination unit  52   b  that update data for the vehicle is available, the update propriety determination unit  52   c  determines whether or not a vehicle condition is a condition suitable for updating a program or the like using a distribution package. Specifically, the update propriety determination unit  52   c  determines whether or not a license contract is established, whether or not a vehicle position is within a predetermined range registered in advance by the user, whether or not a setting of an alarm function of the vehicle is validated, whether or not trouble information regarding the ECU  19  is generated, and determines whether or not a vehicle condition is a condition suitable for downloading a distribution package. That is, the update propriety determination unit  52   c  determines whether or not the vehicle is a vehicle in which a program would be updated against the intention of the user, or a vehicle in which installation would fail after download even when the download is successful. 
     When it is determined that the license contract is established, the vehicle position is within a predetermined range registered in advance by the user, the setting of the alarm function of the vehicle is validated, and the trouble information regarding the ECU  19  is not issued, the update propriety determination unit  52   c  determines that the vehicle condition is a condition suitable for updating a program or the like using a distribution package. The update propriety determination unit  52   c  determines that the vehicle condition is not a condition suitable for updating a program or the like using a distribution package when it is determined that at least any of the following is true: the license contract is not established, the vehicle position is not within a predetermined range registered in advance by the user, the setting of the alarm function of the vehicle is not validated, and the trouble information regarding the ECU  19  is generated. 
     The campaign information transmission unit  52   d  transmits campaign information to the master device  11  when the update propriety determination unit  52   c  determines that the vehicle condition is a condition suitable for updating a program or the like using a distribution package. The campaign information transmission unit  52   d  does not transmit the campaign information to the master device  11  when it is determined by the update propriety determination unit  52   c  that the vehicle condition is not a condition suitable for updating a program or the like using a distribution package. The campaign information transmission unit  52   d  performs the determination described above, and thus stores information regarding a vehicle in which the campaign information is not transmitted to the master device  11 . The center device  3  may display the information regarding a vehicle in which the campaign information is not transmitted to the master device  11 . 
     Next, an operation of the distribution package transmission determination unit  52  in the center device  3  will be described with reference to  FIG. 54 . The center device  3  executes a distribution package transmission determination program and performs a distribution package transmission determination process. 
     When the distribution package transmission determination process is initiated, the center device  3  acquires software information from the vehicle side (S 101 ; corresponding to a software information acquisition step). That is, the center device  3  determines whether or not software update for the vehicle is available. The center device  3  determines availability of update data for the vehicle on the basis of the acquired software information (S 102 ; corresponding to an update availability determination step). When it is determined that update data for the vehicle is available (S 102 : YES), the center device  3 , it is determined whether the vehicle condition is in a condition suitable for updating the program or the like using the distribution package (S 103 ; corresponding to an update propriety determination step). When it is determined that the vehicle condition is a condition suitable for updating a program or the like using a distribution package (S 103 : YES), the center device  3  transmits campaign information to the master device  11  (S 104 ; corresponding to a campaign information transmission step), and finishes the distribution package transmission determination process. 
     When it is determined that update data for the vehicle is not available (S 102 : NO), the center device  3  transmits, to the master device  11 , information indicating that the vehicle is not a distribution package transmission target, that is, update of an application program is not available (S 105 ), and finishes the transmission determination process of the distribution package. When it is determined that the vehicle condition is not a condition suitable for updating a program or the like using the distribution package (S 103 : NO), the center device  3  transmits, to the master device  11 , information indicating that the vehicle condition is not suitable for updating a program or the like and the reason therefor (S 106 ), and finishes the distribution package transmission determination process. In this case, the master device  11  displays, on the in-vehicle display  7 , the information indicating that the vehicle condition is not suitable for updating a program or the like and the reason therefor. For example, when a license contract is not established, the master device  11  displays the content that “the program cannot be updated because the license is not valid; please contact your dealer” on the in-vehicle display  7 . Consequently, it is possible to present the reason why the vehicle condition is not suitable for updating a program or the like to the user, and thus to present appropriate information to the user. 
     As described above, the center device  3  can determine whether or not a condition is suitable for updating a program or the like using a distribution package by performing the distribution package transmission determination process before transmitting the distribution package to the master device  11  and before transmitting campaign information. The center device  3  can transmit campaign information to the master device  11  so as to transmit a distribution package to the master device  11  only in a case where it is determined that a condition is suitable for updating a program or the like using the distribution package. 
     The center device  3  can transmit the campaign information to the master device  11  in a case where a license contract is established, a vehicle position is within a predetermined range registered in advance by the user, a setting of an alarm function of the vehicle is validated, and trouble information regarding the ECU  19  is not generated as a case where a condition is suitable for updating a program or the like using a distribution package. That is, the center device  3  can prevent a situation in which the campaign information is transmitted to the master device  11  even if the license contract is not established, the vehicle position is out of a predetermined range such as a position far away from the home, the setting of the alarm function of the vehicle is invalidated, or the trouble information regarding the ECU  19  is generated. As described above, the center device  3  can prevent the campaign information from being transmitted to the master device  11  for a vehicle in which a program update would be unintended for the user, or installation would fail after download even when the download is successful. 
     The center device  3  may perform the distribution package transmission determination process during transmission of a distribution package. In this case, when it is determined that a vehicle condition is suitable for updating a program using the distribution package during the transmission of the distribution package, the center device  3  continues the transmission of the distribution package, but, when it is determined that the vehicle condition is not suitable for updating a program using the distribution package during transmission of the distribution package, the center device stops transmission of the distribution package. That is, the center device  3  stops the transmission of the distribution package, for example, when trouble information regarding the ECU  19  is issued during the transmission of the distribution package. 
     Next, a description will be made of a process in the master device  11  that has received the campaign information transmitted from the center device  3 . The distribution package download determination process in the master device  11  will be described with reference to  FIGS. 55 and 56 . The vehicle program rewriting system  1  performs the distribution package download determination process in the master device  11 . The above-described distribution package transmission determination process (1) is a determination process performed by the center device  3  in the campaign notification phase before the download phase, but the distribution package download determination process is a determination process performed by the master device  11  in the download phase. In the present embodiment, a description will be made of a case where the DCM  12  performs the distribution package download determination process in the master device  11 , but the CGW  13  may have the function of the DCM  12  to perform the distribution package download determination process. 
     As illustrated in  FIG. 55 , the DCM  12  includes a campaign information receiving unit  67   a , a downloadability determination unit  67   b , and a download execution unit  67   c  in the distribution package download determination unit  67 . The campaign information receiving unit  67   a  receives campaign information from the center device  3 . When the campaign information is received from the center device  3 , the campaign notification icon  501   a  illustrated in  FIG. 32  is displayed. When the campaign information is received by the campaign information receiving unit  67   a , the downloadability determination unit  67   b  determines whether or not a vehicle condition is a condition in which the distribution package is downloadable. That is, the downloadability determination unit  67   b  determines whether or not a radio wave environment for communicating with the center device  3  is favorable, whether or not a remaining battery charge of the vehicle battery  40  is equal to or greater than a predetermined capacity, and whether or not a free memory capacity of the DCM  12  is equal to or larger than a predetermined capacity, and determines whether or not a vehicle condition is a condition in which the distribution package is downloadable. 
     When it is determined that the radio wave environment is favorable, the remaining battery charge of the vehicle battery  40  is equal to or greater than the predetermined capacity, and the free memory capacity of the DCM  12  is equal to or larger than the predetermined capacity, the downloadability determination unit  67   b  determines that the vehicle condition is a condition in which the distribution package is downloadable. The downloadability determination unit  67   b  determines that the vehicle condition is not a condition in which the distribution package is downloadable when it is determined that at least any of the following is true: the radio wave environment is not favorable, and the remaining battery charge of the vehicle battery  40  is not equal to or greater than the predetermined capacity, and the free memory capacity of the DCM  12  is not equal to or larger than the predetermined capacity. 
     As mentioned above, the downloadability determination unit  67   b  determines whether or not there is a possibility that the download cannot be completed normally. The determination in the downloadability determination unit  67   b  is performed on the condition that the “download initiation” button  503   a  is operated by the user on the download approval screen  503  illustrated in  FIGS. 34 and 35 . The downloadability determination unit  67   b  may be configured to determine a determination item in the center device  3 . That is, the downloadability determination unit  67   b  determines that the vehicle is in a downloadable condition, for example, in a case where the setting of the alarm function of the vehicle is validated or the trouble information regarding the ECU  19  is not generated. 
     The download execution unit  67   c  downloads the distribution package from the center device  3  when the downloadability determination unit  67   b  determines that the vehicle condition is a condition in which the distribution package is downloadable. That is, the download execution unit  67   c  executes download of the distribution package after confirming that the download can be completed normally. 
     The download execution unit  67   c  does not download the distribution package from the center device  3  when the downloadability determination unit  67   b  determines that the vehicle condition is not a condition in which the distribution package is downloadable. That is, the download execution unit  67   c  does not execute download of the distribution package in a case where there is a possibility that the download cannot be completed normally. In this case, the download execution unit  67   c  instructs the in-vehicle display  7  to display a pop-up screen indicating that the download cannot be initiated and the reason therefor on the navigation screen  501 . 
     Next, a description will be made of an operation of the distribution package download determination unit  67  in the master device  11  with reference to  FIG. 56 . The master device  11  executes a distribution package download determination program and thus performs the distribution package download determination process. 
     The master device  11  receives campaign information from the center device  3  when the distribution package download determination process is initiated (S 201 ; corresponding to a campaign information receipt step). The master device  11  determines whether or not a vehicle condition is a condition in which the distribution package is downloadable (S 202 ; corresponding to a downloadability determination step). When it is determined that the vehicle condition is a condition in which the distribution package is downloadable (S 202 : YES), the master device  11  downloads the distribution package corresponding to the campaign from the center device  3  (S 203 ; corresponding to a download execution step), and finishes the distribution package download determination process. When it is determined that the vehicle condition is not a condition in which the distribution package is downloadable (S 202 : NO), the master device  11  does not download the distribution package from the center device  3  and ends the distribution package download determination process. 
     As described above, the master device  11  can determine whether or not a vehicle condition is a condition in which a distribution package is downloadable by performing the distribution package download determination process before downloading the distribution package from the center device  3 . The master device  11  can download the distribution package only when the vehicle condition is a condition in which the distribution package is downloadable. 
     The master device  11  can download the distribution package from the center device  3  when the radio wave environment is favorable, the remaining battery charge of the vehicle battery  40  is equal to or greater than the predetermined capacity, and the free memory capacity of the DCM  12  is equal to or larger than the predetermined capacity, as a case suitable for downloading the distribution package. That is, in a case where the radio wave environment is not favorable, the remaining battery charge of the vehicle battery  40  is less than the predetermined capacity, or the free memory capacity of the DCM  12  is smaller than the predetermined capacity, it is possible to prevent a situation in which the distribution package is downloaded from the center device  3 . 
     The master device  11  may perform the distribution package download determination process during download of the distribution package. In this case, when it is determined that the vehicle condition is a condition in which the distribution package is downloadable during download of the distribution package, the master device  11  continues download of the distribution package from the center device  3 , but, when it is determined that the vehicle condition is not a condition in which the distribution package is downloadable during download of the distribution package, the master device stops download of the distribution package from the center device  3 . That is, the master device  11  stops download of the distribution package, for example, in a case where the radio wave environment becomes unfavorable, the remaining battery charge of the vehicle battery  40  becomes less than the predetermined capacity, or the free memory capacity of the DCM  12  becomes smaller than the predetermined capacity, during download of the distribution package. 
     In the above-described way, the center device  3  determines whether or not the vehicle is a vehicle in which a program update would be unintended for the user, or installation would be likely to fail, and the master device  11  determines whether or not there is a possibility that the download would fail in the master device  11 , so that transmission of unnecessary campaign information and a distribution package from the center device  3  to the master device  11  can be avoided. 
     The center device  3  has the following configuration. The center device includes the software information acquisition unit  52   a  acquiring software information of an electronic control unit from a vehicle side, the update availability determination unit  52   b  determining availability of update data for the vehicle on the basis of the software information acquired by the software information acquisition unit, the update propriety determination unit  52   c  determining whether or not a vehicle condition is a condition suitable for update in a case where it is determined by the update availability determination unit that update data is available, and the campaign information transmission unit  52   d  transmitting campaign information regarding update to a vehicle master device in a case where it is determined by the update propriety determination unit that the vehicle condition is a condition suitable for the update. 
     The master device  11  has the following configuration. The master device includes the campaign information receiving unit  67   a  receiving campaign information from a center device, the downloadability determination unit  67   b  determining whether or not a vehicle condition is a condition in which a distribution package is downloadable in a case where the campaign information is received by the campaign information receiving unit, and the download execution unit  67   c  downloading the distribution package from the center device in a case where it is determined by the downloadability determination unit that the vehicle condition is a condition in which the distribution package is downloadable. 
     (3) Write Data Transfer Determination Process, (4) Write Data Acquisition Determination Process, and (5) Installation Instruction Determination Process 
     The write data transfer determination process will be described with reference to  FIGS. 57 and 58 , the write data acquisition determination process will be described with reference to  FIGS. 59 and 60 , and the installation instruction determination process will be described with reference to  FIGS. 61 to 64 . The vehicle program rewriting system  1  performs the write data transfer determination process in the DCM  12 . Here, a state is assumed in which a distribution package transmitted from the center device  3  to the DCM  12  is unpackaged, and write data is extracted from the distribution package. 
     As illustrated in  FIG. 57 , the DCM  12  includes an acquisition request receiving unit  68   a  and a communication state determination unit  68   b  in the write data transfer determination unit  68 . The acquisition request receiving unit  68   a  receives an acquisition request for a write data from the CGW  13 . When the acquisition request of the write data is received by the acquisition request receiving unit  68   a , the communication state determination unit  68   b  determines a state of data communication between the center device  3  and the DCM  12 , for example, in a case where a transfer feasibility determination flag set in advance by the user has a first predetermined value. The transfer feasibility determination flag has, for example, 1 (first predetermined value) in a case where a predetermined condition is checked during installation, 0 (second predetermined value) in a case where the check is omitted. The write data transfer unit  64  transfers the write data to the CGW  13  on the condition that the communication state determination unit  68   b  determines that the data communication between the center device  3  and the DCM  12  is in a connection state. 
     Next, with reference to  FIG. 58 , an operation of the write data transfer determination unit  68  in the DCM  12  will be described. The DCM  12  executes a write data transfer determination program and thus performs the write data transfer determination process. Here, a description will be made of a process in a case where the CGW  13  requests the DCM  12  to acquire the write data in response to an installation instruction from the center device  3 . 
     When it is determined that an acquisition request for the write data from the CGW  13  has been received, the DCM  12  initiates the write data transfer determination process. When the write data transfer determination process is initiated, the DCM  12  determines the transfer feasibility determination flag (S 301  and S 302 ). When it is determined that the transfer feasibility determination flag has the first predetermined value (S 301 : YES), the DCM  12  determines a state of data communication between the center device  3  and the DCM  12  (S 303 ). When it is determined that the data communication between the center device  3  and the DCM  12  is in a connection state (S 303 : YES), the DCM  12  transfers the write data to the CGW  13  (S 304 ) and finishes the write data transfer determination process. When it is determined that the data communication between the center device  3  and the DCM  12  is not in a connection state but in a disconnection state (S 303 : NO), the DCM  12  does not transfer the write data to the CGW  13  and finishes the write data transfer determination process. 
     When it is determined that the transfer feasibility determination flag has the second predetermined value (S 302 : YES), the DCM  12  transfers the write data to the CGW  13  without determining a state of the data communication between the center device  3  and the DCM  12 , and finishes the write data transfer determination process. 
     As described above, the DCM  12  performs the write data transfer determination process prior to transfer of the write data to the CGW  13 , and determines a state of a data communication between the center device  3  and the DCM  12  in a case where the transfer feasibility determination flag has the first predetermined value. When it is determined that the data communication is in a connection state, the DCM  12  initiates transfer of the write data, and when it is determined that the data communication is in a disconnection state, the DCM  12  waits without initiating transfer of the write data. In a situation in which data communication with the center device  3  is possible, the write data can be transferred to the CGW  13 , and installation can be performed in the rewrite target ECU  19 . 
     For example, in a case where there are a plurality of rewrite target ECUs  19  and installation takes time, the in-vehicle-side system  4  can notify the center device  3  of an installation progress situation, and the mobile terminal  6  can display the progress situation one by one. The DCM  12  may perform the write data transfer determination process during transfer of the write data. In this case, when it is determined that data communication is in a connection state during the transfer of the write data, the DCM  12  continues the transfer of the write data, but when it is determined that the data communication is in a disconnection state during the transfer of the write data, the DCM stops the transfer of the write data. 
     Next, the write data acquisition determination process will be described. The vehicle program rewriting system  1  performs the write data acquisition determination process in the CGW  13 . (3) The write data transfer determination process is a determination process performed by the DCM  12  in the installation phase, and the write data acquisition determination process is a determination process performed by the CGW  13  in the same installation phase. 
     As illustrated in  FIG. 59 , the CGW  13  includes an event occurrence determination unit  76   a  and a communication state determination unit  76   b  in the write data acquisition determination unit  76 . The event occurrence determination unit  76   a  determines the occurrence of an event of an acquisition request (installation instruction) for the write data from the center device  3 . When the occurrence of the event of the acquisition request of the write data is determined by the event occurrence determination unit  76   a , the communication state determination unit  76   b  determines a state of data communication between the center device  3  and the DCM  12 , for example, in a case where an acquisition feasibility determination flag set in advance by the user has a first predetermined value. The acquisition feasibility determination flag has, for example, 1 (first predetermined value) when a predetermined condition during installation, 0 (second predetermined value) in a case where the check is omitted. Here, the event occurrence determination unit  76   a  may determine the event occurrence on the basis of the user having given an instruction for installation, and determines that an event of an acquisition request for the write data has occurred, for example, when a notification that the user has performed an installation instruction (refer to  FIG. 39 ) on the in-vehicle display  7  is received. 
     Next, with reference to  FIG. 60 , an operation of the write data acquisition determination unit  76  in the CGW  13  will be described. The CGW  13  executes a write data acquisition determination program and thus performs the write data acquisition determination process. 
     When it is determined that the event of the request to acquire the write data has occurred, the CGW  13  initiates the write data acquisition determination process. When the write data acquisition determination process is initiated, the CGW  13  determines the acquisition feasibility determination flag (S 401  and S 402 ). When it is determined that the acquisition feasibility determination flag has the first predetermined value (S 401 : YES), the CGW  13  determines a state of data communication between the center device  3  and the DCM  12  (S 403 ). When it is determined that data communication between the center device  3  and the DCM  12  is a connection state (S 403 : YES), the CGW  13  transmits an acquisition request for the write data to the DCM  12  (S 404 ), and finishes the write data acquisition determination process. Thereafter, when the write data is transferred from the DCM  12 , the CGW  13  distributes the transferred write data to the rewrite target ECU  19 . When it is determined that the data communication between the center device  3  and the DCM  12  is not in a connection state but is in a disconnection state (S 403 : NO), the CGW  13  does not transmit the acquisition request for the write data to the DCM  12  and finishes the write data acquisition determination process. 
     When it is determined that the acquisition feasibility determination flag has the second predetermined value (S 402 : YES), the CGW  13  transmits an acquisition request the write data to the DCM  12  without determining a state of the data communication between the center device  3  and the DCM  12 , and finishes the write data acquisition determination process. 
     As described above, the CGW  13  performs the write data acquisition determination process prior to acquisition of the write data from the DCM  12 , and determines a state of the data communication between the center device  3  and the DCM  12  in a case where the acquisition feasibility determination flag has the first predetermined value. When it is determined that the data communication is in a connection state, the CGW  13  initiates acquisition of the write data, and, when it is determined that the data communication is in a disconnection state, the CGW waits without initiating acquisition of the write data. In a situation in which communication with the center device  3  is possible, the write data can be acquired from the DCM  12 , and installation can be performed in the rewrite target ECU  19 . 
     For example, in a case where there are a plurality of rewrite target ECUs  19  and installation takes time, the in-vehicle-side system  4  can notify the center device  3  of an installation progress situation, and the mobile terminal  6  can display the progress situation one by one. The CGW  13  may perform the write data acquisition determination process during acquisition of the write data. In this case, when it is determined that the data communication is in a connection state during the acquisition of the write data, the CGW  13  continues the acquisition of the write data, but when it is determined that the data communication is in a disconnection state during the acquisition of the write data, the CGW stops the acquisition of the write data. 
     Next, the write data acquisition determination described above will be described in more detail. Acquisition of the write data is one of the processes related to installation, and the installation instruction determination process will be described here with reference to  FIGS. 61 to 64 . The vehicle program rewriting system  1  performs the installation instruction determination process in the CGW  13 . (1) The distribution package transmission determination process and (2) the distribution package download determination process are determination processes performed in the download phase, (3) the write data transfer determination process and (4) the write data acquisition determination process are processes performed in the installation phase after download is completed, and (5) the installation instruction determination process is a process performed in the installation phase and the activation phase. Here, a state is assumed in which a distribution package is downloaded to the DCM  12 , and, as illustrated in  FIG. 10 , the write data (update data or difference data) for the write target ECU  19  is unpackaged. 
     As illustrated in  FIG. 61 , the CGW  13  includes an installation condition determination unit  77   a , an installation instruction unit  77   b , a vehicle condition information acquisition unit  77   c , an activation condition determination unit  77   d , and an activation instruction unit  77   e  in the installation instruction determination unit  77 . The installation condition determination unit  77   a  determines whether or not a first condition, a second condition, a third condition, a fourth condition, and a fifth condition are established. The first condition is a condition that the user&#39;s approval for installation is obtained. The user approval for installation indicates a user&#39;s approval operation for installation (for example, pressing the “immediate update” button  506   a ) on the screen illustrated in  FIG. 39 , for example. Alternatively, operations from download to activation may be regarded as one update, and the user&#39;s approval operation for update may be regarded as the above user&#39;s approval operation for installation. 
     The second condition is a condition that the CGW  13  can perform data communication with the center device  3 . The third condition is a condition that a vehicle condition is an installable condition. The fourth condition is a condition that installation can be performed in the rewrite target ECU  19 . Here, the fourth condition includes not only that installation can be performed in a rewrite target ECU  19  which is an installation target, but also that installation can be performed in another rewrite target ECU  19  that cooperates with the rewrite target ECU  19  which is the installation target. The fifth condition is a condition that the write data is normal data. Here, the normal data includes data suitable for the rewrite target ECU  19 , data that is not falsified, and the like. 
     When it is determined by the installation condition determination unit  77   a  that all of the first condition, the second condition, the third condition, the fourth condition, and the fifth condition are established, the installation instruction unit  77   b  instructs the rewrite target ECU  19  to install an application program. That is, when the installation instruction unit  77   b  obtains the user&#39;s approval for the installation, the CGW  13  can perform data communication with the center device  3 , the vehicle condition is an installable condition, the installation can be performed in the rewrite target ECU  19 , and it is determined by the installation condition determination unit  77   a  that the write data is normal data, the rewrite target ECU  19  is instructed to install the application program. Specifically, the installation instruction unit  77   b  acquires the write data from the DCM  12 , and transfers the acquired write data to the rewrite target ECU  19 . When it is determined by the installation condition determination unit  77   a  that at least any of the first condition, the second condition, the third condition, the fourth condition, and the fifth condition is not established, the installation instruction unit  77   b  does not instruct the rewrite target ECU  19  to install the application program, and waits or presents to the user information indicating that installation cannot be initiated and the reason therefor. 
     The vehicle condition information acquisition unit  77   c  acquires vehicle condition information from the center device  3 . The activation condition determination unit  77   d  determines whether or not a sixth condition, a seventh condition, and an eighth condition are established when the installation of the application program has been completed in all of the rewrite target ECUs  19 . The sixth condition is a condition that the user&#39;s approval for activation is obtained. The user&#39;s approval for the activation indicates the user&#39;s approval operation (for example, pressing the “OK” button  508   b ) for the activation on the screen illustrated in  FIG. 43 , for example. Alternatively, operations from download to activation may be regarded as one update, and the user&#39;s approval operation for update may be regarded as the above-mentioned approval operation for activation. The seventh condition is a condition that the vehicle condition is an activatable condition. The eighth condition is a condition that the rewrite target ECU  19  is in an activatable condition. 
     When it is determined by the activation condition determination unit  77   d  that all of the sixth condition, the seventh condition, and the eighth condition are established, the activation instruction unit  77   e  instructs the rewrite target ECU  19  to activate the application program. A detailed description will be made of the activation request instruction process (12) which will be described later. That is, the activation instruction unit  77   e  instructs the rewrite target ECU  19  to activate the application program when the activation condition determination unit  77   d  determines that the user&#39;s approval for the activation is obtained, the vehicle condition is an activatable condition, and the rewrite target ECU  19  is in an activatable condition. The activation is performed, and thus an update program written in the rewrite target ECU  19  is validated. When it is determined by the activation condition determination unit  77   d  that at least any of the sixth condition, the seventh condition, and the eighth condition is not established, the activation instruction unit  77   e  does not instruct the rewrite target ECU  19  to activate the application program, and waits or presents to the user information indicating that the activation cannot be initiated and the reason therefor. 
     Next, an operation of the installation instruction determination unit  77  in the CGW  13  will be described with reference to  FIGS. 62 to 64 . The CGW  13  executes an installation instruction determination program and thus performs the installation instruction determination process. 
     When the installation instruction determination process is initiated, the CGW  13  determines whether or not the first condition is established, and determines whether or not the user&#39;s approval for the installation is obtained (S 501 ; corresponding to a part of an installation condition determination step). When it is determined that the user&#39;s approval for installation is obtained (S 501 : YES), the CGW  13  determines whether or not the second condition is established, and determines whether or not data communication with the center device  3  is available (S 502 ; corresponding to a part of the installation condition determination step). The CGW  13  determines whether or not data communication with the center device  3  is available on the basis of a communication radio wave status in the DCM  12 . 
     When it is determined that data communication with the center device  3  is possible (S 502 : YES), the CGW  13  determines whether or not the third condition is established, and determines whether or not a vehicle condition is an installable condition (S 503 ; corresponding to a part of the installation condition determination step). The CGW  13  determines, as the vehicle condition, for example, whether or not a remaining battery charge of the vehicle battery  40  is equal to or greater than a predetermined capacity, or whether or not the vehicle is in a parking state (IG OFF state) in a case where a memory configuration of the rewrite target ECU  19  is a single-bank memory, and thus determines whether or not the vehicle condition is an installable condition. The condition of the vehicle condition may refer to received rewrite specification data (refer to  FIG. 8 ). The CGW  13  determines that the vehicle condition is an installable condition, for example, in a case where a remaining battery charge of the vehicle battery  40  is equal to or greater than a predetermined capacity specified in the rewrite specification data, and the vehicle condition matches a vehicle condition (installable only in a parking state, installable only in a traveling state, or installable in both the parking state and the traveling state) specified in the rewrite specification data. 
     When it is determined that the vehicle condition is an installable condition (S 503 : YES), the CGW  13  determines whether or not the fourth condition is established, and determines whether or not the rewrite target ECU  19  is in an installable condition (S 504 ; corresponding to a part of the install condition determination step). The CGW  13  determines that the rewrite target ECU  19  is in an installable condition, for example, when a trouble code is not generated in the rewrite target ECU  19  and security access to the rewrite target ECU  19  is successful. Here, whether or not the trouble code is generated may be checked not only for the rewrite target ECU  19  to which the write data is written but also for another ECU  19  performing cooperative control with the rewrite target ECU  19 . That is, the CGW  13  determines whether or not the trouble code is generated not only for the rewrite target ECU  19  but also for the ECU  19  performing cooperative control with the rewrite target ECU  19 . 
     When it is determined that the rewrite target ECU  19  is an installable condition (S 504 : YES), the CGW  13  determines whether or not the fifth condition is established, and determines whether or not the write data is normal data (S 505 ; corresponding to a part of an installation condition determination step). The CGW  13  determines that the write data is normal data when the write data matches a write bank (inactive bank) of the rewrite target ECU  19 , and a verification result of the integrity of the write data is normal. When it is determined that the write data is normal data (S 505 : YES), the CGW  13  instructs the rewrite target ECU  19  to install the application program (S 506 ; corresponding to an installation instruction step), and thus the CGW  13  performs determination of the second condition and the subsequent conditions on the condition that the first condition is satisfied. The CGW  13  determines the fifth condition at the end. When it is determined that all of the first to fifth conditions are established, the CGW  13  instructs the rewrite target ECU  19  to install the application program. 
     On the other hand, when the CGW  13  determines that the user&#39;s approval for installation is not obtained (S 501 : NO), determines that data communication with the center device  3  is not possible (S 502 : NO), determines that the vehicle condition is not an installable condition (S 503 : NO), determines that the rewrite target ECU  19  is not in an installable condition (S 504 : NO), or determines that the write data is not normal data (S 505 : NO), the CGW does not instruct the rewrite target ECU  19  to install the application program. In the above-described process, a configuration has been described in which the condition that the user&#39;s approval for installation is obtained is determined prior to determination of the other conditions, but a configuration in which the condition is determined after determination of the other conditions may be used. 
     When the CGW  13  instructs the rewrite target ECU  19  to install the application program, the CGW distributes the write data to the rewrite target ECU  19  (S 507 ), and determines whether or not the installation has been completed (S 508 ). When it is determined that the installation has been completed (S 508 : YES), the CGW  13  determines whether or not the sixth condition is established, and determines whether or not the user&#39;s approval for the activation is obtained (S 509 ). When it is determined that the user&#39;s approval for the activation is obtained (S 509 : YES), the CGW  13  determines whether or not the seventh condition is established, and determines whether or not the vehicle condition is an activatable condition (S 510 ). 
     When it is determined that the vehicle condition is an activatable condition (S 510 : YES), the CGW  13  determines whether or not the eighth condition is established, and determines whether or not the rewrite target ECU  19  is in an activatable condition (S 511 ). When it is determined that the rewrite target ECU  19  is in an activatable condition (S 511 : YES), the CGW  13  instructs the rewrite target ECU  19  to perform activation (S 512 ). As mentioned above, when it is determined that all of the sixth condition to the eighth condition are established, the CGW  13  instructs the rewrite target ECU  19  to perform activation. 
     When there are a plurality of rewrite target ECUs  19 , the CGW  13  may individually or collectively give an instruction for installation. In a case where the rewrite target ECUs  19  are the ECU (ID 1 ) and the ECU (ID 2 ), in an aspect of individually giving an instruction for the installation, the CGW  13  determines whether or not installation conditions are established for the ECU (ID 1 ), as illustrated in  FIG. 63 . When it is determined that the installation conditions are established for the ECU (ID 1 ), the CGW  13  instructs the ECU (ID 1 ) to perform installation. Next, the CGW  13  determines whether or not installation conditions are established for ECU (ID 2 ). Here, the CGW  13  may determine whether or not the fourth condition and the fifth condition are established for ECU (ID 2 ) as the installation conditions. When it is determined that the installation conditions are established for the ECU (ID 2 ), the CGW  13  instructs the ECU (ID 2 ) to perform installation. 
     When the rewrite target ECUs  19  are the ECU (ID 1 ) and the ECU (ID 2 ), in an aspect of collectively giving an instruction for installation, the CGW  13  determines whether or not installation conditions are established for the ECU (ID 1 ), as illustrated in  FIG. 64 . That is, the CGW  13  determines the first to third conditions, and the fourth and fifth conditions for the ECU (ID 1 ). When it is determined that the installation conditions are established for the ECU (ID 1 ), the CGW  13  determines whether or not installation conditions are established for the ECU (ID 2 ). That is, the CGW  13  determines the fourth condition and the fifth condition for ECU (ID 2 ). When the installation conditions are established for the ECU (ID 2 ), the CGW  13  instructs the ECU (ID 1 ) and the ECU (ID 2 ) to perform installation. For example, the CGW  13  simultaneously perform transfer of rewrite data to the ECU (ID 1 ) and transfer of rewrite data to the ECU (ID 2 ) in parallel. As described above, in the aspect of collectively giving an instruction for installation, the CGW  13  determines the first condition to the third condition, and the fourth condition and the fifth condition for all the rewrite target ECUs. The CGW  13  gives an instruction for installation after all of the conditions are satisfied. 
     As described above, the CGW  13  performs the installation instruction determination process before instructing the rewrite target ECU  19  to install an application program, and thus instructs the rewrite target ECU  19  to install the application program when determining that all of the first condition that the user&#39;s approval for the installation is obtained, the second condition that data communication with the center device  3  is possible, the third condition that a vehicle condition is an installable condition, the fourth condition that the rewrite target ECU  19  is in an installable condition, and the fifth condition that the write data is normal data are established. It is possible to appropriately instruct the rewrite target ECU  19  to install an application program. 
     (6) Security Access Key Management Process 
     The security access key management process will be described with reference to  FIGS. 65 to 69 . A security access key is used to authenticate a device when the CGW  13  accesses the rewrite target ECU  19  before write data is installed. The vehicle program rewriting system  1  performs the security access key management process in the CGW  13 . Here, a description will be made assuming that the CGW  13  is in a state of being able to acquire the write data from the DCM  12  through (3) the write data transfer determination process or (4) the write data acquisition determination process. The device authentication using the security access key corresponds to the fourth condition (step S 505 ) in (5) the installation instruction determination process described above. 
     When the CGW  13  distributes the write data to the rewrite target ECU  19 , the CGW  13  is required to perform security access (device authentication) with the rewrite target ECU  19  by using the security access key. In this case, a method is considered in which the CGW  13  requests the rewrite target ECU  19  to generate a random number value, acquires the random number value generated by the rewrite target ECU  19  from the rewrite target ECU  19 , generates a security access key by computing the acquired random number value. However, in such a method, in a case where the random number value is acquired from the rewrite target ECU  19  even when an application program is not rewritten, the security access key can be stored, so that there may be a risk of security access key leakage. 
     In a configuration in which the CGW  13  transmits a random number value acquired from the rewrite target ECU  19  to the center device  3 , and the center device  3  generate a security access key by computing the random number value, it is not necessary to store the security access key, and thus it is possible to reduce the risk of security access key leakage. However, in the configuration in which the center device  3  computes the random number value, the waiting time until the rewrite target ECU  19  acquires the random number value from the center device  3  is increased, and thus it is difficult to satisfy the time specification for the diagnosis communication. In view of such circumstances, the present embodiment employs the following configuration. 
     As illustrated in  FIG. 65 , the supplier generates a random number value by encrypting a security access key for each rewrite target ECU  19  by using an encryption/decryption key of the security access key. The random number value mentioned here is a random value including both a value different from the value used in the past or a value same as the value used in the past. The random number value is an encrypted security access key. The supplier provides the generated random number value along with reprogramming data. The security access key, the encryption/decryption key of the security access keys, and the random number value are unique keys to each the ECU  19 . 
     When the OEM is provided with the random number value along with the reprogramming data from the supplier, the OEM correlates the provided random number value with an ECU (ID) for identifying the ECU  19 , and stores the random number value into the CGW rewrite specification data illustrated in  FIG. 8 . The OEM also stores a key pattern or a decryption operation pattern necessary for decrypting the random number value into the CGW rewrite specification data. As the key pattern, a method such as a common key/public key, a key length, and the like are stored, and, as the decryption operation pattern, the type of algorithm used for a decryption operation and the like are stored. When the OEM stores the random number value, the key pattern, and the decryption operation pattern into the CGW rewrite specification data, the OEM provides the CGW rewrite specification data storing the random number value to the center device  3  along with the reprogramming data. The information provided from the supplier is stored in an ECU reprogramming data DB and an ECU metadata DB, which will be described later. 
     When rewrite specification data (DCM rewrite specification data and CGW rewrite specification data) is provided along with the reprogramming data from the OEM, the center device  3  transmits a distribution package including the provided rewrite specification data and reprogramming data to the master device  11 . In the master device  11 , when the distribution package is downloaded from the center device  3 , the DCM  12  transfers the rewrite specification data and write data to the CGW  13 . 
     As illustrated in  FIG. 66 , the CGW  13  includes a secure area  78   a  (corresponding to a decryption key storage unit), a random number value extraction unit  78   b  (corresponding to a key derivation value extraction unit), a key pattern extraction unit  78   c , a decryption operation pattern extraction unit  78   d , a key generation unit  78   e , a security access execution unit  78   f , a session transition request unit  78   g , and a key erasure unit  78   h  in the security access key management unit  78 . In the secure area  78   a , information therein cannot be read from the outside of the ECU  19 , and an encryption/decryption key of a security access key and a decryption operation algorithm are located. The random number value extraction unit  78   b  extracts, from an analysis result of the CGW rewrite specification data, a random number value (key derivation value) included in the rewrite specification data. The random number value is a value encrypted in correlation with the ECU (ID) of the rewrite target ECU  19 . 
     The key pattern extraction unit  78   c  extracts, from an analysis result of the CGW rewrite specification data, a key pattern included in the rewrite specification data. The decryption operation pattern extraction unit  78   d  extracts, from an analysis result of the CGW rewrite specification data, a decryption operation pattern included in the rewrite specification data. 
     When the random number value is extracted by the random number value extraction unit  78   b , the key generation unit  78   e  searches the secure area  78   a , decrypts the extracted random number value by using a decryption key corresponding to the ECU (ID) from a bundle of decryption keys of the security access key located in the secure area  78   a , and generates the security access key. In this case, the key generation unit  78   e  decrypts the key derivation value according to a decryption operation method specified by the decryption operation pattern extracted by the decryption operation pattern extraction unit  78   d  by using a decryption key specified by the key pattern extracted by the key pattern extraction unit  78   c . That is, a plurality of key patterns and a plurality of decryption operation patterns are prepared, and a key pattern and a decryption operation pattern are specified by the CGW rewrite specification data, and thus the key generation unit  78   e  generates a security access key by using the key pattern and the decryption operation pattern. 
     When the security access key is generated by the key generation unit  78   e , the security access execution unit  78   f  executes security access to the rewrite target ECU  19  by using the generated security access key. Specifically, the security access execution unit  78   f  transmits encrypted data in which an ECU (ID) is encrypted by using, for example, a security access key, and requests access to the rewrite target ECU  19 . When receiving the encrypted data, the rewrite target ECU  19  decrypts the received encrypted data by using the security access key held by itself. The rewrite target ECU  19  compares decrypted data generated through the decryption with an ECU (ID) thereof, and permits access to the rewrite target ECU in a case where the data matches the ECU (ID), and does not permit access thereto in a case where the data does not match the ECU (ID). 
     The session transition request unit  78   g  requests transition to a rewrite session. After transition from a default session to the rewrite session, the security access execution unit  78   f  executes security access. After transition to a session (for example, a diagnosis session) other than the default session, security access may be performed, and then transition to the rewrite session may occur. The key erasure unit  78   h  erases the security access key generated by the key generation unit  78   e  after the security access to the rewrite target ECU  19  is executed by the security access execution unit  78   f  and rewriting of an application program in the rewrite target ECU  19  is completed. 
     Next, an operation of the security access key management unit  78  in the CGW  13  will be described with reference to  FIGS. 67 to 69 . The CGW  13  executes a security access key management program and thus performs the security access key management process. The CGW  13  performs a security access key generation process and a security access key erasure process as the security access key management process. Hereinafter, each process will be described in order. 
     (6-1) Security Access Key Generation Process 
     When the security access key generation process is initiated, the CGW  13  analyzes rewrite specification data acquired from the DCM  12  (S 601 ; corresponding to a rewrite specification data analysis procedure), and extracts a random number value, a key pattern, and a decryption operation pattern from CGW rewrite specification data (S 602 ; corresponding to a key derivation value extraction procedure). 
     The CGW  13  searches the secure area  78   a , decrypts the random number value extracted from the CGW rewrite specification data by using a decryption key corresponding to an ECU (ID) from a bundle of decryption keys of a security access key located in the secure area  78   a , and generates the security access key (S 603 ; corresponding to a key generation procedure). 
     As illustrated in  FIG. 68 , the CGW  13  generates the security access key from the CGW rewrite specification data. The CGW  13  makes a session transition request for transition to a rewrite session that makes write data writable (S 604 ) and executes the security access to the rewrite target ECU  19  by using the security access key (S 605 ). When execution of the security access has been completed, the CGW  13  distributes the write data to the rewrite target ECU  19  (S 606 ) and makes a session maintenance request (S 607 ). When it is determined that installation has been completed (S 608 : YES), the CGW  13  finishes the security access key generation process. 
     (6-2) Security Access Key Deletion Process 
     When the security access key erasure process is initiated, the CGW  13  determines whether or not rewriting of the application program in the rewrite target ECU  19  has been completed (S 611 ). When it is determined that rewriting of the application program in the rewrite target ECU  19  has been completed (S 611 : YES), the CGW  13  executes the security access key generation process to erase the generated security access key (S 612 ), and finishes the security access key erasure process. 
     As described above, the CGW  13  executes the security access key management process, extracts a random number value corresponding to the rewrite target ECU  19  from an analysis result of rewrite specification data, decrypts the random number value by using a decryption key corresponding to the rewrite target ECU  19  stored in the secure area  78   a , and generates a security access key. The CGW  13  generates a security access key without acquiring the security access key from the outside, and thus security access to the rewrite target ECU  19  can be appropriately executed while reducing the risk of security access key leakage. 
     When there are a plurality of the rewrite target ECUs  19 , it is desirable for the CGW  13  to generate a security access key immediately before each piece of write data is installed. In other words, in a case where rewrite target ECUs  19  are the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ), it is desirable for the CGW  13  to execute processes of generating a security access key of the ECU (ID 1 ), installing write data into the ECU (ID 1 ), generating a security access key of the ECU (ID 2 ), installing write data into the ECU (ID 2 ), generating a security access key of the ECU (ID 3 ), and installing write data into the ECU (ID 3 ) in this order. For example, as illustrated in  FIG. 63 , the CGW  13  performs a security access process as one of whether or not installation conditions for the ECU (ID 1 ) are established, and instructs the ECU (ID 1 ) to perform installation in a case where access is normally permitted. Thereafter, the CGW  13  performs a security access process as one of whether or not installation conditions for the ECU (ID 2 ) are established, and instructs the ECU (ID 2 ) to perform installation in a case where access is normally permitted. 
     When the CGW  13  performs security access to the rewrite target ECU  19  which then permits access thereto, the rewrite target ECU unlocks the security access by receiving a session transition request from the CGW  13 , and thus makes write data writable into the flash memory. The session transition request is, for example, a “rewrite session transition request” in a second state illustrated in  FIG. 155 . Unless the rewrite target ECU  19  receives the session transition request from the CGW  13  within a predetermined time (for example, 5 seconds) after permitting access thereto, the rewrite target ECU times out, locks the security access, and does not accept reception of the session transition request. In a case where the CGW  13  does not transmit the session transition request to the rewrite target ECU  19  within a predetermined time after specifying permission for access to the rewrite target ECU  19 , the CGW is required to transmit a session maintenance request to the rewrite target ECU  19 , retain the rewrite target ECU  19  not to time out, and transmit the session transition request to the rewrite target ECU  19 . 
     For example, when a campaign notification to the version 2.0 occurs by canceling an operation in the middle of rewriting in a state in which an application program of the version 1.0 is written in an active bank-And an application program of the version 2.0 is written in an inactive bank, and when from this state, it is preferable that only activation is performed without performing installation, and thus the security access process may be omitted. 
     (7) Write Data Verification Process 
     The write data verification process will be described with reference to  FIGS. 70 to 78 . The vehicle program rewriting system  1  verifies write data in the CGW  13 . The CGW  13  may perform the write data verification process described in the present embodiment before acquiring an access permission in (6) the security access key management process, or may perform the write data verification process after acquiring the access permission. 
     As illustrated in  FIG. 70 , when the write data is generated, the supplier or the OEM generates a data verification value by applying a data verification value calculation algorithm to the generated write data. Here, the write data may be a new program to be updated, or may be difference data between an old program and a new program. The supplier or OEM generates an authenticator by applying encryption using a predetermined key (key value) to the data verification value, and registers the write data and the authenticator in the center device  3  in correlation with each other. Specifically, the data is stored for each ECU  19  in the reprogramming data DB which will be described later. The center device  3  generates a distribution package including the write data and the authenticator, and stores the distribution package into the package DB. 
     When a download request for the distribution package from the master device  11  is generated, the center device  3  transmits the distribution package including the write data and the authenticator to the master device  11  in response to the download request. In this case, the write data transmitted from the center device  3  to the master device  11  is ciphertext, and the authenticator transmitted from the center device  3  to the master device  11  is also ciphertext. The authenticator transmitted from the center device  3  to the master device  11  may be plaintext. When the authenticator transmitted from the center device  3  to the master device  11  is plaintext, a decryption process which will be described later is not necessary. 
     When the distribution package is downloaded from the center device  3 , the master device  11  extracts the write data for the rewrite target ECU  19  from the downloaded distribution package, and verifies validity of the write data before distributing the write data to the rewrite target ECU  19 . That is, the master device  11  sequentially executes a decryption process, a first verification value calculation process, a second verification value calculation process, a comparison process, and a determination process, and thus verifies the write data. The decryption process is a process of decrypting the authenticator transmitted in the ciphertext. The first verification value calculation process is a process of calculating a first data verification value that is an expected value, from the decrypted authenticator by using the key (key value). The second verification value calculation process is a process of calculating a second data verification value from the write data by using the data verification value calculation algorithm. The comparison process is a process of comparing the first data verification value with the second data verification value. The determination process is a process of determining validity of the write data on the basis of a comparison result in the comparison process. 
     As illustrated in  FIG. 71 , the CGW  13  includes a writability determination unit  79   a , a process execution request unit  79   b , a process result acquisition unit  79   c , and a verification unit  79   d  in the write data verification unit  79 . The writability determination unit  79   a  determines whether or not write data can be written in the rewrite target ECU  19 . When it is determined by the writability determination unit  69   a  that the write data can be written in the rewrite target ECU  19 , the process execution request unit  79   b  notifies the DCM  12  of a process execution request and thus requests the DCM  12  to execute a process. The process execution request unit  68   b  notifies the DCM  12  of a request for executing at least any of the decryption process, the first verification value calculation process, the second verification value calculation process, the comparison process, and the determination process. The process result acquisition unit  68   c  is notified of a process result from the DCM  12  and thus acquires the process result from the DCM  12 . When the process result is acquired by the process result acquisition unit  68   c , the verification unit  79   d  verifies the write data by using the process result. That is, in the configuration, the CGW  13  corresponds to a first device and a first functional unit, and the DCM  12  corresponds to a second device and a second functional unit. 
     Next, an operation of the write data verification unit  79  in the CGW  13  will be described with reference to  FIGS. 72 to 77 . The CGW  13  executes the verification program of the write data and performs the verification process of the write data. 
     When the write data verification process is initiated, the CGW  13  notifies the DCM  12  of a process execution request and thus requests the DCM  12  to execute a process (S 701 ; corresponding a process execution request procedure). The CGW  13  notifies the DCM  12  of a process execution request for at least any of the decryption process, the first verification value calculation process, the second verification value calculation process, the comparison process, and the determination process. When a process result is acquired from the DCM  12  (S 702 ; corresponding to a process result acquisition procedure), the CGW  13  verifies the write data by using the acquired process result (S 703 ; corresponding to a verification procedure). 
     Hereinafter, some cases where the CGW  13  notifies the DCM  12  of a process execution request will be exemplified. In an example illustrated in  FIG. 73 , the CGW  13  notifies the DCM  12  of process execution requests for the decryption process, the first verification value calculation process, and the second verification value calculation process. When the DCM  12  is notified of the process execution requests for the decryption process from the CGW  13 , the first verification value calculation process, and the second verification value calculation process, the DCM sequentially executes the decryption process, the first verification value calculation process, and the second verification value calculation process. The DCM  12  executes a process result notification process, and notifies the CGW  13  of a first data verification value calculated through the first verification value calculation process and a second data verification value calculated through the second verification value calculation process as process results. When the CGW  13  executes a process result acquisition process and acquires the first data verification value and the second data verification value from the DCM  12 , the CGW sequentially executes the comparison process and the determination process by using the first data verification value and the second data verification value. The CGW  13  verifies the write data on the basis of the correctness of a determination result in the determination process. In this example, the DCM  12  stores a key for calculating the first data verification value. 
     In an example illustrated in  FIG. 74 , the CGW  13  notifies the DCM  12  of process execution requests for the decryption process and the second verification value calculation process. When the DCM  12  is notified of the process execution requests for the decryption process and the second verification value calculation process from the CGW  13 , the DCM sequentially executes the decryption process and the second verification value calculation process, and notifies the CGW  13  of a second data verification value calculated through the second verification value calculation process. When the CGW  13  executes a process result acquisition process and acquires the second data verification value from the DCM  12 , the CGW executes the first verification value calculation process, and sequentially executes the comparison process and the determination process by using the first data verification value calculated through the first verification value calculation process and the second data verification value. The CGW  13  verifies the write data on the basis of the correctness of a determination result in the determination process. In this example, the CGW  13  stores a key for calculating the first data verification value. 
     In the example illustrated in  FIG. 75 , the CGW  13  notifies the DCM  12  of process execution requests for the decryption process, the first verification value calculation process, the second verification value calculation process, and the comparison process. When the DCM  12  is notified of the process execution requests for the decryption process, the first verification value calculation process, the second verification value calculation process, and the comparison process from the CGW  13 , the DCM sequentially executes the decryption process, the first verification value calculation process, the second verification value calculation process, and the comparison process. The DCM  12  executes a process result notification process, and notifies the CGW  13  of a comparison result in the comparison process as a process result. When the CGW  13  executes a process result acquisition process and acquires the comparison result from the DCM  12 , the CGW executes the determination process by using the comparison result. The CGW  13  verifies the write data on the basis of the correctness of a determination result in the determination process. In this example, the DCM  12  stores a key for calculating the first data verification value. 
     In an example illustrated in  FIG. 76 , the CGW  13  notifies the DCM  12  of process execution requests for the decryption process, the first verification value calculation process, the second verification value calculation process, the comparison process, and the determination process. When the DCM  12  is notified of the process execution requests for the decryption process, the first verification value calculation process, the second verification value calculation process, the comparison process, and the determination process from the CGW  13 , the DCM sequentially executes the decryption process, the first verification value calculation process, the second verification value calculation process, the comparison process, and the determination process. The DCM  12  executes a process result notification process, and notifies the CGW  13  of a determination result in the determination process as a process result. When the CGW  13  executes a process result acquisition process, and acquires the process result from the DCM  12 , the CGW verifies the write data on the basis of the correctness of the determination result indicated by the process result. In this example, the DCM  12  stores a key for calculating the first data verification value. 
     In a case where there are a plurality of rewrite target ECUs  19 , the CGW  13  performs a verification process on write data for two or more the rewrite target ECUs  19  as follows. In a case where there are a plurality of rewrite target ECUs  19 , the CGW  13  has a method of collectively verifying write data for the plurality of rewrite target ECU  19  and a method of individually verifying write data. 
     In the method of collectively verifying the write data for a plurality of rewrite target ECUs  19 , as illustrated in  FIG. 77 , the CGW  13  collectively verifies write data of the ECU (ID 1 ), write data of the ECU (ID 2 ), and write data of the ECU (ID 3 ), distributes the write data of the ECU (ID 1 ) to the write target ECU (ID 1 ), distributes the write data of the ECU (ID 2 ) to the write target ECU (ID 2 ), and distributes the write data of the ECU (ID 3 ) to the write target ECU (ID 3 ). In this case, the pieces of write data of the plurality of rewrite target ECUs  19  are collectively verified, and thus it is possible to reduce the time required from initiation of verification of the write data of the plurality of rewrite target ECUs  19  to completion of rewriting of a program. That is, it is possible to reduce the time required from initiation of verification of pieces of write data of a plurality of rewrite target ECUs  19  to completion of rewriting of a program more than in a configuration in which the pieces of write data of the plurality of rewrite target ECUs  19  are individually verified. 
     In the method of individually verifying the write data of a plurality of rewrite target ECUs  19 , as illustrated in  FIG. 78 , the CGW  13  verifies write data of the ECU (ID 1 ), distributes the write data of the ECU (ID 1 ) to the write target ECU (ID 1 ), verifies write data of the ECU (ID 2 ), distributes the write data of the ECU (ID 2 ) to the write target ECU (ID 2 ), verifies write data of the ECU (ID 3 ), and distributes the write data of the ECU (ID 3 ) to the write target ECU (ID 2 ). In this case, the write data is verified immediately before the write data is distributed, and therefore it is possible to prevent illegal access and thus to increase reliability. In other words, in the configuration in which the write data is collectively verified for a plurality of rewrite target ECUs  19 , the time from completion of verification according to a rewrite order to distribution of the write data varies depending on the rewrite order, and, when the time from completion of verification to distribution of the write data increases, there is concern that there is a risk of falsification due to illegal access during that time, but such a situation can be prevented by verifying the write data immediately before the write data is distributed. 
     As described above, the CGW  13  performs write data verification process, and thus causes the DCM  12  downloading a distribution package from the center device  3  to execute at least some of the processes related to verification of the write data. Even though an area for storing write data cannot be allocated or a verification computation program cannot be installed in the CGW  13  or the rewrite target ECU  19 , the write data can be appropriately verified before the write data is written to the rewrite target ECU  19 . 
     In the configuration in which the CGW  13  illustrated in  FIG. 74  performs the first verification value calculation process, since the CGW  13  stores the key (key value) and performs the verification process without transmitting the key to the DCM  12 , security can be increased compared with a configuration in which the DCM  12  performs the first verification value calculation process. In a case where there are a plurality of rewrite target ECUs  19 , the first verification value calculation process may be performed by using a common key (key value) that is common to the plurality of rewrite target ECUs  19 , and the first verification value calculation process may be performed by using different individual keys (key values) in the plurality of rewrite target ECUs  19 . 
     As described above, although the configuration in which the CGW  13  notifies the DCM  12  of the process execution request has been exemplified, for example, in a case where a processing load increases in the DCM  12  and thus a problem occurs in an original process, a navigation apparatus or an ECU other than the rewrite target ECU  19  may be used instead of the DCM  12  to notify the navigation apparatus or the ECU other than the rewrite target ECU  19  of the process execution request. In a case where the DCM  12  and the CGW  13  are integrated with each other and can cope with an original process without causing a problem, the process execution request may be requested to the process execution unit of the process execution unit itself. For example, the process may be performed between different software components in the same ECU. The above-described configuration may be applied to the master device  11  configured as one integrated ECU having the functions of the DCM  12  and the CGW  13 . For example, in  FIGS. 73 to 76 , the process function in the CGW  13  is set as a first functional unit, and the process function in the DCM  12  is set as a second functional unit, and the first functional unit notifies the second functional unit of a process execution request, and an execution result is returned from the second functional unit to the first functional unit. In the master device  11  configured as an integrated ECU, in a case where a processing load increases and thus a problem occurs in a communication process or a relay process, the navigation apparatus or an ECU other than the rewrite target ECU  19  may be notified of a process execution request instead of the second functional unit. 
     As the data verification value, a single value may be calculated for the entire application program, and a plurality of values may be calculated for respective blocks of the application program. When the write data is entire data, the data verification value may be used for integrity verification after the write data is completed. 
     Whereas the security access is a method for verifying whether or not the CGW  13  and the rewrite target ECU  19  are connectable, verification of the write data includes the concepts that the center device  3  which is a distribution destination of the write data is approved (connection and mutual authentication through TLS communication), a communication channel for downloading the write data from the center device  3  is approved (communication channel concealment or encryption), the write data downloaded from the center device  3  is not falsified (falsification detection), and the write data downloaded from the center device  3  cannot be falsified (encryption). 
     The write data at the time of rewriting a new program has been described, but the same applies to write data during rollback at the time of rollback to an old program. In this case, the CGW  13  may verify the write data during rollback at the time of downloading the write data from the center device  3 , but may verify the rollback write data immediately before the rollback write data is distributed to the rewrite target ECU  19  when a write cancellation request is generated. 
     (8) Data Storage Bank Information Transmission Control Process 
     The data storage bank information transmission control process will be described with reference to  FIGS. 79 to 81 . The vehicle program rewriting system  1  performs the data storage bank information transmission control process in the CGW  13 . 
     As illustrated in  FIG. 79 , the CGW  13  includes a data storage bank information acquisition unit  80   a , a data storage bank information transmission unit  80   b , a rewrite method specifying unit  80   c , and a rewrite method instruction unit  80   d  in the data storage bank information transmission control unit  80 . The data storage bank information acquisition unit  80   a  acquires information regarding hardware and software from the respective ECUs  19  as ECU configuration information. Specifically, in a case of a double-bank memory ECU and a single-bank suspend memory ECU having a plurality of data storage banks, a software ID including version information of each of the data storage banks and information that can specify an active bank-A are acquired as double-bank rewrite information (hereinafter, referred to as bank information). 
     When the ECU configuration information including the bank information is acquired by the data storage bank information acquisition unit  80   a , the data storage bank information transmission unit  80   b  transmits the acquired bank information from the DCM  12  to the center device  3  as one of the ECU configuration information. The data storage bank information transmission unit  80   b  may transmit the ECU configuration information to the center device  3  each time the IG switch  42  switches between an ON state and an OFF state, and may transmit the ECU configuration information to the center device  3  in response to a request from the center device  3 . The data storage bank information transmission unit  80   b  may transmit the ECU configuration information not only to a double-bank memory ECU and a single-bank suspend memory ECU but also to a single-bank memory ECU along with an ECU configuration including the bank information. 
     The rewrite method specifying unit  80   c  specifies a rewrite method on the basis of an analysis result of rewrite specification data for the CGW  13 . The rewrite method indicates a power supply switching method during installation in the rewrite target ECU  19 . When the rewrite method is specified by the rewrite method specifying unit  80   c , the rewrite method instruction unit  80   d  instructs the rewrite target ECU  19  to rewrite an application program according to the specified rewrite method. That is, when a rewrite method based on self-retention power is specified by the rewrite method specifying unit  80   c , the rewrite method instruction unit  80   d  instructs the rewrite target ECU  19  to rewrite an application program based on the self-retention power. When a rewrite method based on power supply control is specified by the rewrite method specifying unit  80   c , the rewrite method instruction unit  80   d  instructs the rewrite target ECU  19  to rewrite an application program based on the power supply control without using the self-retention power. 
     Next, with reference to  FIGS. 80 and 81 , an operation of the data storage bank information transmission control unit  80  in the CGW  13  will be described. The CGW  13  executes a data storage bank information transmission control program, and thus performs the data storage bank information transmission control process. 
     When the data storage bank information transmission control process is initiated, the CGW  13  transmits an ECU configuration information request including the bank information to all of the ECUs  19  (S 801 ), and acquires ECU configuration information including the bank information from all of the ECUs  19  (S 802 ; corresponding to a data storage bank information acquisition step). When the ECU configuration information is acquired from each rewrite target ECU  19 , the CGW  13  transmits the acquired ECU configuration information to the DCM  12  (S 803 ; corresponding to a data storage bank information transmitting step), and waits for write data and rewrite specification data to be acquired from the DCM  12  (S 804 ). Here, in a case where the rewrite target ECU  19  is specified in advance, the CGW  13  may acquire bank information or the like from only the specified rewrite target ECU  19 . 
     When the ECU configuration information is received from the CGW  13 , the DCM  12  temporarily stores the received ECU configuration information, and transmits the ECU configuration information to the center device  3  at a timing of transmitting (uploading) the ECU configuration information to the center device  3 . When the ECU configuration information is received from the DCM  12 , the center device  3  stores and analyzes the received ECU configuration information. 
     The center device  3  specifies a version of an application program on each bank of each ECU  19  that is a transmission source of the bank information and which bank is an active bank, and specifies write data compliant to the version of the application program and the active bank corresponding to the specified double banks (corresponding to an update data selection step). For example, in a case where the bank-A is an active bank, the application program stored in the active bank has the version 2.0, the bank-B is an inactive bank, and the application program stored in the inactive bank has the version 1.0, the center device  3  specifies write data of the version 3.0 for the bank-B as the write data. In a case where the write data is difference data, the center device  3  specifies the difference data for update from the version 1.0 to the version 3.0. When the write data is specified, the center device  3  transmits a distribution package including the specified write data and rewrite specification data to the DCM  12  (corresponding to a distribution package transmission step). 
     The center device  3  may statically select or dynamically generate a distribution package to be transmitted to the DCM  12 . In a case where the center device  3  statically selects the distribution package to be transmitted to the DCM  12 , the center device manages a plurality of distribution packages in which the write data is stored, selects write data compliant to an inactive bank, selects a distribution package including the selected write data from among the plurality of distribution packages, and transmits the selected distribution package to the DCM  12 . In a case where the center device  3  dynamically generates a distribution package to be transmitted to the DCM  12 , when write data compliant to the inactive bank is specified, the center device generates a distribution package including the specified write data and transmits the generated distribution package to the DCM  12 . 
     When the distribution package is downloaded from the center device  3 , the DCM  12  extracts the write data and the rewrite specification data from the downloaded distribution package, and transfers the extracted write data and rewrite specification data to the CGW  13 . 
     When it is determined that the write data and the rewrite specification data are acquired from the DCM  12  (S 804 : YES), the CGW  13  analyzes the acquired rewrite specification data (S 805 ), and determines a rewrite method for the rewrite target ECU  19  on the basis of an analysis result of the rewrite specification data (S 806  and S 807 ). 
     When it is determined that the rewrite method is a rewrite method using self-retention power (S 806 : YES), the CGW  13  transmits a write data acquisition request to the DCM  12  on the condition of being in an installable vehicle condition, acquires the write data from the DCM  12 , distributes the acquired write data to the rewrite target ECU  19 , rewrites the application program by using self-retention power (S 808 ), and terminates the data storage bank information transmission control process. The method of rewriting the application program by using the self-retention power is the same as described in (b) Case where a application program is rewritten by using self-retention power with reference to  FIGS. 28 and 29  described above. 
     When it is determined that a rewrite method is rewriting based on power supply control (S 807 : YES), the CGW  13  transmits a write data acquisition request to the DCM  12  on the condition that the vehicle is parked, acquires write data from the DCM  12 , distributes the acquired write data to the rewrite target ECU  19 , rewrites the application program using the power supply control (S 809 ), and terminates the data storage bank information transmission control process. The method of rewriting the application program by using the power supply control is the same as described in (a) Case where application program is rewritten by using power supply control with reference to  FIGS. 26 and 27 . 
     As described above, the CGW  13  performs the data storage bank information transmission control process, and thus notifies the center device  3  of ECU configuration information including bank information, and downloads a distribution package including write data compliant to the ECU configuration information from the center device  3  to the DCM  12 . The CGW  13  acquires write data compliant to the bank information from the DCM  12  and distributes the write data to the rewrite target ECU  19 . In a case where the ECU  19  equipped with a flash memory having double data storage banks is a rewrite target, an application program can be appropriately rewritten. 
     As an aspect in which the center device  3  distributes the distribution package, there are the following first to third distribution aspects. In the first distribution aspect, the center device  3  distributes a single distribution package storing, for example, write data of the version 2.0 for the bank-A and write data of the version 2.0 for the bank-B. The DCM  12  extracts the write data of the version 2.0 for the bank-A and the write data of the version 2.0 for the bank-B from the distribution package downloaded from the center device  3 , and transfers the extracted write data to the CGW  13 . When the write data of the version 2.0 for the bank-A and the write data of the version 2.0 for the bank-B are transferred from the DCM  12 , the CGW  13  selects one of the two pieces of write data and distributes the selected write data to the rewrite target ECU  19 . That is, there is a configuration in which write data corresponding to each data storage bank is included in a distribution package, and rewrite data suitable for the rewrite target ECU  19  is selected in the master device  11 . 
     In the second distribution aspect, the center device  3  selects and distributes either a distribution package storing write data of the version 2.0 for the bank-A or a distribution package storing write data of the version 2.0 for the bank-B, for example. The DCM  12  extracts the write data from the distribution package downloaded from the center device  3  and transfers the extracted write data to the CGW  13 . The CGW  13  distributes the write data transferred from the DCM  12  to the rewrite target ECU  19 . That is, there is a configuration in which the center device  3  selects a distribution package including inactive bank write data on the basis of bank information uploaded from the DCM  12 . 
     In the third distribution aspect, the center device  3  distributes a distribution package storing, for example, write data of the version 2.0 shared by the bank-A and the bank-B. The DCM  12  extracts the write data of the version 2.0 shared by the bank-A and the bank-B from the distribution package downloaded from the center device  3 , and transfers the extracted write data to the CGW  13 . The CGW  13  distributes the write data of the version 2.0 shared by the bank-A and the bank-B transferred from the DCM  12  to the rewrite target ECU  19 . When the write data of the version 2.0 shared by the bank-A and the bank-B is received from the CGW  13 , the rewrite target ECU  19  writes the received write data to either the bank-A or the bank-B. In this case, when an application program is executed in the rewrite target ECU  19 , an address solving function of the microcomputer works, so that the rewrite target ECU  19  is appropriately operated even when the write data is written to either the bank-A or the bank-B. That is, the microcomputer of the write target ECU  19  solves a differences between execution addresses due to a difference between the banks such that the center device  3  and the master device  11  can be operated without being aware of the banks. 
     The ECU configuration information including the bank information transmitted from the CGW  13  to the center device  3  via the DCM  12  may include not only information for specifying a version of an application program and an active bank corresponding to the double banks but also vehicle specifying information, system specifying information, ECU specifying information, usage environment information, and the like. 
     The vehicle specifying information is unique information for specifying a vehicle that is a distribution destination of a distribution package, and is, for example, a vehicle identification number (VIN). In vehicles that fall under the on-board diagnostics (OBD) regulations, a VIN can be used in accordance with provisions of the OBD regulations, but in vehicles that do not fall under the OBD Regulations, such as EV vehicles, the VIN is not available, and thus individual vehicle identification information may be used instead of the VIN. 
     The system specifying information is unique information for identifying the type of reprogramming system. The CGW  13  can perform wireless rewriting for a system in which wired rewriting using diagnosis communication managed by the CGW can be performed, but cannot perform wireless rewriting for other individual systems. That is, this is because the system updates a program that is acquired in a wireless manner by using an update mechanism of a program acquired in a wired manner. Thus, it is necessary for the center device  3  to determine which distribution package is to be distributed to which system, and it is possible to manage which system is mounted on the vehicle by using the system specifying information. The center device  3  can determine a rewrite method for each system, a rewrite order in a case where a plurality of systems are rewrite targets, and the like by determining the system specifying information. 
     The ECU specifying information is unique information for specifying the rewrite target ECU  19 , and is information including a software version for uniquely specifying the rewrite ECU and an application program written in the rewrite target ECU  19 , and a hardware version. The ECU specifying information also corresponds to an ECU part number. In a case where the latest software is written with entire data, only the hardware version is required. It is also possible to define information that can be specified by an application program, such as a specification version or a configuration version, and to further define a microcomputer ID, a sub-microcomputer ID, a flash ID, a software child version, a software grandchild version, and the like. 
     The usage environment information is unique information for specifying an environment in which the user uses the vehicle. When the usage environment information is transmitted from the CGW  13  to the center device  3  via the DCM  12 , the center device  3  can distribute an application program suitable for the environment in which the user is using the vehicles. It is possible to distribute application programs suitable for environments in which users use vehicles, for example, application programs specialized for acceleration are distributed to users who prefer sudden acceleration driving from the time of stop, and application programs that are inferior in acceleration performance but specialized for eco-driving are distributed to users who prefer eco-driving. 
     As described above, the case has been described in which the flash memory is mounted on the microcomputer of the rewrite target ECU  19 , but, in a case where an external memory is connected to the microcomputer of the rewrite target ECU  19 , the external memory is processed as the same as a double-bank memory, and write data is written by dividing a write area of the external memory into two areas. In a case where the flash memory is mounted on the microcomputer of the rewrite target ECU  19  and the external memory is connected, a program stored in the external memory may be temporarily copied to a memory of the microcomputer in some cases. Since the external memory may generally be used as a storage area of an operation log of the ECU, it is desirable to stop storing the operation log in a case where writing of write data to the external memory is initiated, and to resume storing of the operation log in a case where writing of the write data to the external memory has been completed. 
     The same applies to a case of rewriting map data because there is a concept of double banks and a version not only in a case of rewriting an application program but also in a case of data having the property of being updated one by one, such as the map data. 
     (9) Non-Rewrite Target Power Supply Management Process 
     The power supply management process for the non-rewrite target ECU  19  will be described with reference to  FIGS. 82 to 87 . The vehicle program rewriting system  1  performs the power supply management process for the non-rewrite target ECU  19  in the CGW  13 . In the present embodiment, a situation is assumed in which download of a distribution package has been completed by the DCM  12 , the CGW  13  acquires a rewrite specification data, and the CGW  13  distributes a write data to the rewrite target ECU  19  while the vehicle is in a parking state. In a case where the write data is distributed to the rewrite target ECU  19 , the CGW  13  requests the power supply management ECU  20  to turn on the IG power to bring all of the ECUs  19  into an active state. 
     As illustrated in  FIG. 82 , the CGW  13  includes a rewrite target specifying unit  81   a , an installability determination unit  81   b , a state transition control unit  81   c , and a rewrite order specifying unit  81   d  in the power supply management unit  81  of the non-rewrite target ECU  19 . The rewrite target specifying unit  81   a  specifies the rewrite target ECU  19  and the non-rewrite target ECU  19  on the basis of an analysis result of the rewrite specification data. The installability determination unit  81   b  determines whether or not installation is feasible in the rewrite target ECU  19 . 
     The state transition control unit  81   c  can change a state of the ECU  19 , and control the ECU  19  in a stop state or a sleep state to transition to an active state (wake-up state), or control the ECU  19  in the active state to transition to the stop state or the sleep state. The state transition control unit  81   c  causes the ECU  19  in a normal operating state to transition to a power saving operating state or causes the ECU  19  in the power saving operating state to transition to the normal operating state. When it is determined by the installability determination unit  81   b  that the installation is feasible, the state transition control unit  81   c  controls at least one non-rewrite target ECU  19  to be in the stop state, the sleep state, or the power saving operating state. The rewrite order specifying unit  81   d  specifies a rewrite order for the rewrite targets ECU  19  on the basis of the analysis result of the rewrite specification data. 
     Next, a description will be made of an operation of the power supply management unit  81  of the non-rewrite target ECU  19  in the CGW  13  will be described with reference to  FIGS. 83 to 87 . The CGW  13  executes a non-rewrite target power supply management program and thus performs a non-rewrite target power supply management process. Here, a description will be made of a case where the ECUs  19  that are management targets are brought into an active state by the CGW  13 . 
     When the power supply management process for the non-rewrite target ECU  19  is initiated, the CGW  13  specifies the rewrite target ECUs  19  and the non-rewrite target ECUs  19  on the basis of an analysis result of the CGW rewrite specification data (S 901 ), and specifies a rewrite order of one or more rewrite target ECUs  19  on the basis of the analysis result of the rewrite specification data (S 902 ). When the CGW  13  determines whether or not write data can be written (S 903 ; corresponding to a writability determination procedure) and determines that the write data can be written (S 903 : YES), the CGW transmits a power-off request (stop request) to the non-rewrite target ECU  19  of the ACC system and the non-rewrite target ECU  19  of the IG system, and thus causes the non-rewrite target ECU  19  of the ACC system and the non-rewrite target ECU  19  of the IG system to transition from the active state to the stop state (S 904 ; corresponding to a state transition control procedure). 
     When the CGW  13  determines whether or not transmission of the power-off request to all of the corresponding ECUs  19  has been completed (S 905 ), and determines that transmission of the power-off request to all of the corresponding ECUs  19  has been completed (S 905 : YES), the CGW transmits a sleep request to the non-rewrite target ECU  19  of the +B power system, and thus causes the non-rewrite target ECU  19  of the +B power system to transition from the active state to the sleep state (S 906 ; corresponding to a state transition control procedure). 
     When the CGW  13  determines whether or not transmission of the sleep request to all of the corresponding ECUs  19  has been completed (S 907 ), and determines that the transmission of the sleep request to all of the corresponding ECUs  19  has been completed (S 907 : YES), the CGW determines whether or not rewriting of an application program in all of the rewrite target ECUs  19  has been completed (S 908 ). When it is determined that rewriting of the application program has been completed in all of the rewrite target ECUs  19  (S 908 : YES), the CGW  13  finishes the power supply management process for the non-rewrite target ECU  19 . When it is determined that rewriting of the application program is not completed in all of the rewrite target ECUs  19  (S 908 : NO), the CGW  13  returns to step S 904 , and repeatedly performs step S 904  and the subsequent steps. 
     In a case where there are a plurality of rewrite target ECUs  19 , the CGW  13  may individually cause states of the plurality of rewrite target ECUs  19  to transition, or may collectively cause the states of the plurality of rewrite target ECUs  19  to transition. That is,  FIG. 83  illustrates a process in which the CGW  13  transmits a power-off request or a sleep request to the non-rewrite target ECU  19 . In  FIG. 84  and  FIG. 85  described next, a description will be made of a case where the power supply management process for the rewrite target ECU  19  is performed in addition to the power supply management process for the non-rewrite target ECU  19 . 
     First, a description will be made of a case where the CGW  13  individually causes states of a plurality of rewrite target ECUs  19  to transition with reference to  FIG. 84 . As illustrated in  FIG. 84 , for example, a description will be made of a case where the rewrite target ECUs  19  are an ECU (ID 1 ), an ECU (ID 2 ), and an ECU (ID 3 ), and the rewrite target ECUs  19  are sequentially subjected to rewriting during parking in a designated rewrite order of the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ) from the earliest rewrite order. 
     The CGW  13  causes all of the ECU (ID 1 ), ECU (ID 2 ), and ECU (ID 3 ) to transition from the stop state or the sleep state to the active state. The CGW  13  maintains the first rewrite target ECU (ID 1 ) to be in the active state, causes the ECU 
     (ID 2 ) and the ECU (ID 3 ) to transition from the active state to the stop state or the sleep state, and distributes the write data to the ECU (ID 1 ). When the distribution of the write data to the ECU (ID 1 ) has been completed, the CGW  13  causes the ECU (ID 1 ) to transition from the active state to the stop state or the sleep state, causes the second rewrite target ECU (ID 2 ) to transition from the stop state or the sleep state to the active state, maintains the ECU (ID 3 ) to be in the stop state or the sleep state, and distributes the write data to the ECU (ID 2 ). 
     When the distribution of the write data to the ECU (ID 2 ) has been completed, the CGW  13  maintains the ECU (ID 1 ) to be in the stop state or the sleep state, causes the ECU (ID 2 ) to transition from the active state to the stop state or the sleep state, causes the third rewrite target ECU (ID 3 ) to transition from the stop state or the sleep state to the active state, and distributes the write data to the ECU (ID 3 ). When the distribution of the write data to the ECU (ID 3 ) has been completed, the CGW  13  maintains the ECU (ID 1 ) and the ECU (ID 2 ) to be in the stop state or the sleep state, and causes the ECU (ID 3 ) to transition from the active state to the stop state or the sleep state. As mentioned above, the CGW  13  controls only the ECU  19  that is a current rewrite target among the plurality of the rewrite target ECUs  19  to be in the active state. 
     Next, a description will be made a case where the CGW  13  collectively causes states of a plurality of rewrite target ECUs  19  to transition with reference to  FIG. 85 . As illustrated in  FIG. 85 , for example, a description will be made of a case where the rewrite target ECUs  19  are the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ), and the rewrite target ECUs  19  are sequentially subjected to rewriting during parking in a designated rewrite order of the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ) from the earliest rewrite order. 
     The CGW  13  causes all of the ECU (ID 1 ), ECU (ID 2 ), and ECU (ID 3 ) to transition from the stop state or the sleep state to the an active state. The CGW  13  maintains all of the ECU (ID 1 ), ECU (ID 2 ), and ECU (ID 3 ) to be in the active state and distributes the write data to the ECU (ID 1 ). When the distribution of the write data to the ECU (ID 1 ) has been completed, the CGW  13  distributes the write data to the ECU (ID 2 ). When the distribution of the write data to the ECU (ID 2 ) has been completed, the CGW  13  distributes the write data to the ECU (ID 3 ). When the distribution of the write data to the ECU (ID 3 ) has been completed, the CGW  13  causes all of the ECU (ID 1 ), ECU (ID 2 ), and ECU (ID 3 ) to transition from the active state to the stop state or the sleep state. As mentioned above, the CGW  13  controls a plurality of all rewrite target ECUs  19  to be in the active state until installation has been completed in all of the rewrite target ECUs. Here, the CGW  13  may simultaneously distribute write data to the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ) in parallel. 
     In a case where the rewrite target ECU  19  rewrites an application program during parking, a voltage supplied to the rewrite target ECU  19  is not necessarily in a stable environment, and there is concern that exhaustion of the vehicle battery  40  may occur during the rewriting of the application program. Particularly, where there are a plurality of rewrite target ECUs  19 , the time required for rewriting the application program increases, and thus there is a high probability that exhaustion of the vehicle battery  40  may occur during rewriting of the application program. In relation to this fact, the non-rewrite target ECU  19  is brought into the stop state or the sleep state as described above, and thus a situation in which a remaining battery charge of the vehicle battery  40  becomes insufficient during rewriting of a program is prevented in advance. The ECU  19  that is not a current rewrite target among the rewrite target ECUs  19  is brought into the stop state or the sleep state, and thus power consumption can be further reduced. 
     The above description relates to a case where an application program of the rewrite target ECU  19  is rewritten during parking, and a description will be made of a case where an application program of the rewrite target ECU  19  is rewritten while the vehicle is traveling. In a case where the rewrite target ECU  19  rewrites the application program while the vehicle is traveling, a voltage supplied to the rewrite target ECU  19  is in a stable environment, and thus there is no concern that exhaustion of the vehicle battery  40  may occur during the rewriting of the application program, but a remaining battery charge of the vehicle battery  40  may be small. In light of such circumstances, it is desirable to cause the ECU  19  that does not need to perform an operation to transition to the stop state or the sleep state while the vehicle is traveling. As illustrated in  FIG. 86 , although an ECU  44  that does not need to perform an operation is connected to the +B power line  37  while the vehicle is traveling, in a case of a configuration in which the ECU  44  is not connected to the ACC power line  38  and the IG power line  39 , the CGW  13  causes ECU  44  that does not need to perform an operation while the vehicle is traveling to transition from the active state to the stop state or the sleep state. The ECU  44  is, for example, an ECU having a function of preventing theft. That is, the CGW  13  causes the ECU  44  that does not need to perform an operation and is not a rewrite target among all the ECU  19  in the active state while the vehicle is traveling, to transition to the stop state or the sleep state. Consequently, it is possible to suppress an increase in power consumption due to installation while the vehicle is traveling. 
     The CGW  13  monitors a remaining battery charge of the vehicle battery  40 , and performs the above-described non-rewrite target power supply management process. Here, a remaining battery charge monitoring process will be described with reference to  FIG. 87 . When the remaining battery charge monitoring process is initiated, the CGW  13  monitors a remaining battery charge while write data is being distributed to the rewrite target ECU  19  (S 911 ), and determines whether the remaining battery charge is equal to or more than a first predetermined capacity, whether the remaining battery charge is less than the first predetermined capacity and equal to or more than a second predetermined capacity, and whether the remaining battery charge is less than the second predetermined capacity (S 912  to S 914 ). 
     When it is determined that the remaining battery charge is equal to or more than the first predetermined capacity (S 912 : YES), the CGW  13  maintains the non-rewrite target ECU  19  to be in the active state, and continues the distribution of the write data to the rewrite target ECU  19  (S 915 ). When it is determined that the remaining battery charge is less than the first predetermined capacity and is equal to or more than the second predetermined capacity (S 913 : YES), the CGW  13  causes an ECU that does not need to perform an operation during traveling among the non-rewrite target ECUs  19  to transition to the stop state or the sleep state, and continues the distribution of the write data to the rewrite target ECU  19  (S 916 ). When it is determined that the remaining battery charge is less than the second predetermined capacity (S 914 : YES), the CGW  13  determines whether or not rewriting can be stopped (S 917 ). 
     When it is determined that rewriting can be stopped (S 917 : YES), the CGW  13  stops the distribution of the write data (S 918 ). When it is determined that rewriting cannot be stopped (S 917 : NO), the CGW  13  causes all ECUs among the non-rewrite target ECUs  19  that can transition to the stop state or the sleep state to transition to the stop state or the sleep state (S 919 ). 
     When the CGW  13  determines whether or not rewriting has been completed (S 920 ), and determines that rewriting is not completed (S 920 : NO), the CGW returns to step S 911 , and repeatedly performs step S 911  and the subsequent steps. When it is determined that the rewriting has been completed (S 920 : YES), the CGW  13  causes the rewrite target ECU  19  in the stop state or the sleep state to transition to the active state (S 921 ), and finishes the remaining battery charge monitoring process. Here, values of the first predetermined capacity and the second predetermined capacity may be stored in advance by the CGW  13 , or values designated by rewrite specification data may be used. 
     In the step S 919 , the CGW  13  may exclude the ECU  19  having a specific function such as an alarm function from targets that transition to the stop state or the sleep state, and may cause the non-rewrite target ECU  19  to transition from the active state to the stop state or the sleep state except the ECU  19  having the specific function. In a case where the rewrite target ECU  19  can execute application control while an application program is being rewritten, the CGW  13  may bring the non-rewrite target ECU  19  into the stop state or the sleep state except the ECU  19  that can communicate with the rewrite target ECU  19 . The CGW  13  may cause the rewrite target ECU  19  to transition from the stop state or the sleep state to the active state in a case where rewrite conditions are established when all the ECUs  19  are in the stop state or the sleep state, for example, when a vehicle position becomes a predetermined position or the present time reaches a predetermined time. 
     The CGW  13  may group the rewrite target ECUs  19  or the non-rewrite target ECUs  19  on the basis of any of start power (a +B power ECU, an ACC ECU, or an IG ECU), a domain group (a body system, a traveling system, or a multimedia system), and a synchronization timing, and may bring the rewrite target ECU  19  into the active state in the group unit, or may bring the non-rewrite target ECU  19  into the stop state or sleep state in the group unit. 
     The CGW  13  may be configured to control the power supply in the bus unit. That is, when it is determined that all of the ECUs  19  connected to a specific bus are the non-rewrite target ECUs  19 , the CGW  13  may turn off power of the specific bus to cause all of the non-rewrite target ECUs  19  connected to the specific bus to transition to the stop state or the sleep state. 
     As described above, the CGW  13  performs the non-rewrite target power supply management process, and thus brings at least one non-rewrite target ECU  19  into the stop state, the sleep state, or the power saving operating state when it is determined that installation can be performed in the rewrite target ECU  19 . It is possible to prevent a situation in which a remaining battery charge of the vehicle battery  40  becomes insufficient during rewriting of an application program. Since the non-rewrite target ECU  19  is brought into the stop state, the sleep state, or the power saving operating state, it is possible to suppress an increase in communication loads. 
     (10) File Transfer Control Process 
     The file transfer control process will be described with reference to  FIGS. 88 to 97 . The vehicle program rewriting system  1  performs the file transfer control process in the CGW  13 . The present embodiment corresponds to a process of transmitting rewrite data stored the DCM  12  (corresponding to a first device) to the rewrite target ECU  19  (corresponding to a third device) via the CGW  13  (corresponding to a second device). 
     As illustrated in  FIG. 88 , the CGW  13  includes a transfer target file specifying unit  82   a , a first data size specifying unit  82   b , an acquisition information specifying unit  82   c , a second data size specifying unit  82   d , and a divided file transfer request unit  82   e  in the file transfer control unit  82 . The transfer target file specifying unit  82   a  specifies a file including write data to be written to the rewrite target ECU  19  as a transfer target file by using an analysis result of rewrite specification data. For example, in a case where the rewrite target ECUs  19  are the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ), the transfer target file specifying unit  82   a  acquires ECU information of the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ) from the CGW rewrite specification data illustrated in  FIG. 8 , and specifies the file including the write data from the acquired ECU information as a transfer target file. As the transfer target file, an address or an index for acquiring the file may be specified, or a file name of the file may be specified. 
     When the transfer target file is specified by the transfer target file specifying unit  82   a , the first data size specifying unit  82   b  specifies a first data size for acquiring the transfer target file. When the transfer target file is specified by the transfer target file specifying unit  82   a , the acquisition information specifying unit  82   c  specifies an address as acquisition information for acquiring the transfer target file. In the present embodiment, the address is specified as the acquisition information for acquiring the transfer target file, but, as long as the acquisition information is used for acquiring the transfer target file, not only an address but also a file name or an ECU (ID) may be used. The second data size specifying unit  82   d  specifies a second data size for distributing write data to the rewrite target ECU  19 . That is, the first data size is a data transfer size from the DCM  12  to the CGW  13 , and the second data size is a data transfer size from the CGW  13  to the rewrite target ECU  19 . 
     When the address is specified by the acquisition information specifying unit  82   c  and the first data size is specified by the first data size specifying unit  82   b , the divided file transfer request unit  82   e  designates the address and the first data size in the DCM  12 , and requests the DCM  12  to transfer a divided file. For example, in a case where a data amount of a write file to be distributed to the ECU (ID 1 ) is 1M bytes, the divided file transfer request unit  82   e  requests that the write data is transferred from the address of 0x10000000 every 1 k bytes. 
     Next, an operation of the file transfer control unit  82  in the CGW  13  will be described with reference to  FIGS. 89 to 97 . The CGW  13  executes a file transfer control program and thus performs the file transfer control process. 
     When it is determined that an unpackaging completion notification signal is received from the DCM  12 , the CGW  13  initiates the file transfer control process. As illustrated in  FIG. 10 , the unpackaging is a process of dividing a distribution package file into data for each ECU and each piece of rewrite specification data. When the file transfer control process is initiated, the CGW  13  transmits a predetermined address to the DCM  12  (S 1001 ). When the predetermined address is received from the CGW  13 , the DCM  12  transfers the CGW rewrite specification data to the CGW  13  with the reception of the predetermined address as a trigger. The CGW  13  acquires the CGW rewrite specification data due to transfer of the CGW rewrite specification data from the DCM  12  (S 1002 ). 
     When the CGW rewrite specification data is acquired from the DCM  12 , the CGW  13  analyzes the acquired CGW rewrite specification data (S 1003 ), and specifies a transfer target file on the basis of an analysis result of the rewrite specification data (S 1004 ; corresponding to a transfer target file specifying procedure). The CGW  13  specifies an address corresponding to the transfer target file (S 1005 ; corresponding to an acquisition information specifying procedure), and specifies the first data size corresponding to the transfer target file (S 1006 ; corresponding to a first data size specifying procedure). The CGW  13  transmits the specified address and data size to the DCM  12  in accordance with the provisions of Service Identifier (SID)  35 , designates the address and the data size in a memory area, and requests the DCM  12  to transfer a divided file (S 1007 ). 
     When the address and the data size are received from the CGW  13 , the DCM  12  analyzes the DCM rewrite specification data, and transfers a file corresponding to the address and the data size to the CGW  13  as the divided file. The CGW  13  acquires the divided file due to transfer of the divided file from the DCM  12  (S 1008 ). In this case, the CGW  13  may store the acquired file into a RAM and then store the acquired file into a flash memory. 
     The CGW  13  determines whether or not acquisition of all divided files to be acquired has been completed (S 1009 ). For example, in a case where a data amount of a write file to be distributed to the ECU (ID 1 ) is 1M bytes, the CGW  13  acquires a divided file every 1 k bytes and determines whether or not acquisition of the data amount of 1M byte has been completed by repeating the acquisition of the divided file every 1 k bytes. When it is determined that acquisition of all divided files to be acquired is not completed (S 1009 : NO), the CGW  13  returns to step S 1004  and repeatedly performs step S 1004  and the subsequent steps. When it is determined that acquisition of all of the files to be acquired has been completed (S 1009 : YES), the CGW  13  finishes the file transfer control process. In a case where there are a plurality of rewrite target ECUs  19 , the CGW  13  repeatedly performs the file transfer control process on each rewrite target ECU  19 . 
     That is, for example, in a case where the rewrite target ECUs  19  are the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ), the CGW  13  performs the file transfer control process on the ECU (ID 2 ) when distribution of write data to the ECU (ID 1 ) has been completed, and performs the file transfer control process on the ECU (ID 3 ) when distribution of write data to the ECU (ID 2 ) has been completed. The CGW  13  may sequentially perform the transfer control process on a plurality of rewrite target ECUs  19 , and may perform the transfer control process in parallel.  FIG. 90  illustrates, for example, a case where a write data file of the ECU (ID 1 ) is stored at addresses “1000” to “3999”, a write data file of the ECU (ID 2 ) is stored at addresses “4000” to “6999”, and a write data file of the ECU (ID 3 ) is stored at addresses “7000” . . . in the memory of the DCM  12 . 
     In this case, as illustrated in  FIG. 91 , when an unpackaging completion notification signal is received from the DCM  12 , the CGW  13  transmits the address “0000” to the DCM  12 , and acquires rewrite specification data from the DCM  12 . That is, the DCM  12  determines that reception of the address “0000” is a request for acquiring CGW rewrite data, and transmits the CGW rewrite specification data to the CGW  13 . The CGW  13  designates the ECU (ID 1 ) as a transfer target of write data, designates the address “1000” and the data size “1 k bytes”, and acquires a divided file including write data of the ECU (ID 1 ) stored at the addresses “1000” to “1999” from the DCM  12 . When the divided file is acquired from the DCM  12 , the CGW  13  distributes the write data included in the divided file to the ECU (ID 1 ). 
     Subsequently, the CGW  13  similarly designates the ECU (ID 1 ) as a transfer target of write data, designates the address “2000” and the data size “1 k bytes”, and acquires a divided file including write data of the ECU (ID 1 ) stored at the addresses “2000” to “2999” from the DCM  12 . When the divided file is acquired from the DCM  12 , the CGW  13  distributes the write data included in the divided file to the ECU (ID 1 ). The CGW  13  repeatedly acquires the divided file every 1 k bytes from the DCM  12  until writing of all pieces of write data to the ECU (ID 1 ) is completed, and repeatedly distributes the write data included in the divided file to the ECU (ID 1 ). That is, when the write data of 1 k bytes is acquired from the DCM  12 , the CGW  13  transmits the write data of 1 k bytes to the rewrite target ECU  19 , and acquires the next write data of 1 k bytes from the DCM  12  when transmission to the rewrite target ECU  19  has been completed. The CGW  13  repeatedly performs these processes until writing of all pieces of write data is complete. 
     When writing of the write data in the ECU (ID 1 ) is normally completed, the CGW  13  designates the ECU (ID 2 ) as a transfer target of write data, designates the address “4000” and the data size “1 k bytes”, and acquires a divided file including write data of the ECU (ID 2 ) stored at the addresses “4000” to “4999” from the DCM  12 . When the divided file is acquired from the DCM  12 , the CGW  13  distributes the write data included in the divided file to the ECU (ID 2 ). 
     When writing of the write data in the ECU (ID 2 ) is normally completed, the CGW  13  designates the ECU (ID 3 ) as a transfer target of write data, designates the address “7000” and the data size “1 k bytes”, and acquires a divided file including write data of the ECU (ID 2 ) stored at the addresses “7000” to “7999” from the DCM  12 . When the divided file is acquired from the DCM  12 , the CGW  13  distributes the write data included in the divided file to the ECU (ID 2 ). 
     As described above, the CGW  13  performs the file transfer control process, and thus specifies a transfer target file on the basis of an analysis result of rewrite specification data, and specifies an address and a data size corresponding to the transfer target file. The CGW  13  designates the address and the data size in the DCM  12 , requests the DCM  12  to transfer a divided file obtained by dividing the transfer target file, and acquires the divided file from the DCM  12 . Consequently, it is possible to distribute write data to the ECU  19  while storing a large volume of write data in the memory of the DCM  12 . That is, in the CGW  13 , it is not necessary to prepare a memory for storing a large volume of a file and thus to reduce a memory capacity of the CGW  13 . 
     Here, a description will be made of a relationship between a data amount of a divided file transferred from the DCM  12  to the CGW  13  and a data amount of a write file distributed from the CGW  13  to the rewrite target ECU  19 . In the above example, as illustrated in  FIG. 92 , a description has been made of a case where a data amount of a divided file transferred from the DCM  12  to the CGW  13  is 1 k bytes. However, any relationship between a data amount of the divided file transferred from the DCM  12  to the CGW  13  and a data amount of the write file distributed from the CGW  13  to the rewrite target ECU  19  may be employed. 
     That is, for example, when the rewrite target ECU  19  has a specification of receiving the write data in 4 k bytes for the reason of CAN communication, the CGW  13  distributes a data amount of a write file to the rewrite target ECU  19  in the unit of 4 k bytes. In this case, when a data amount of the divided file transferred from the DCM  12  to the CGW  13  is 1 k bytes, the CGW  13  acquires four divided files from the DCM  12  and then distributes 4 k bytes to the rewrite target ECU  19 . That is, a data amount of a divided file transferred from the DCM  12  to the CGW  13  is smaller than a data amount of a write file distributed from the CGW  13  to the rewrite target ECU  19 . In such a relationship, in the CGW  13 , it is possible to acquire a divided file from the DCM  12  and distribute write data to the rewrite target ECU  19  in parallel while suppressing an increase in a memory capacity. 
     That is, when a data amount of a divided file transferred from the DCM  12  to the CGW  13  is 4 k bytes, a memory capacity of the CGW  13  is required to be set to 8 k bytes in order to acquire the divided file from the DCM  12  and distribute write data to the rewrite target ECU  19  in parallel. A data amount of the divided file transferred from the DCM  12  to the CGW  13  is set to 1 k bytes, and thus it is possible to acquire the divided file from the DCM  12  and distribute write data to the rewrite target ECU  19  in parallel without changing the memory capacity of the CGW  13  to 8 k bytes. For example, the memory capacity of the CGW  13  is allocated to 5 k bytes, and the CGW  13  acquires the next 1 k bytes from the DCM  12  while distributing 4 k bytes acquired from the DCM  12  to the rewrite target ECU  19 . The CGW  13  further acquires the next 1 k bytes from the DCM  12  after the distribution of 4 k byte to the rewrite target ECU  19  is completed. 
     On the other hand, for example, when the rewrite target ECU  19  has a specification of receiving the write data in 128 bytes for the reason of CAN communication, the CGW  13  distributes the write data to the rewrite target ECU  19  in 128 bytes. In this case, when a data amount of a divided file transferred from the DCM  12  to the CGW  13  is 1 k bytes, the CGW  13  acquires a single divided file from the DCM  12  and then distributes 128 bytes to the rewrite target ECU  19  at a time. That is, a data amount of the divided file transferred from the DCM  12  to the CGW  13  is larger than a data amount of the write file distributed from the CGW  13  to the rewrite target ECU  19 . For example, a memory capacity of the CGW  13  is allocated to 2 k bytes, and the CGW  13  acquires the next 1 k bytes from the DCM  12  while distributing 1 k bytes acquired from the DCM  12  to the rewrite target ECU  19  in the unit of 128 bytes. The CGW  13  further acquires the next 1 k bytes from the DCM  12  after eight number of times of distribution of 128 bytes to the rewrite target ECU  19  is completed. 
     In the above-described way, a data amount of a divided file transferred from the DCM  12  to the CGW  13  may be set to a fixed value (for example, 1 k bytes), and a data amount of a write file distributed from the CGW  13  to the rewrite target ECU  19  may be set to a variable value in accordance with a specification of the rewrite target ECU  19 . The CGW  13  may determine an amount of data to be distributed to the rewrite target ECU  19  by using a data transfer size of each ECU specified in the rewrite specification data, for example. 
     The CGW  13  transmits a transfer request to the DCM  12  and requests the DCM  12  to transfer a divided file, and there are a first request aspect and a second request aspect as aspects of requesting the DCM  12  to transfer the divided file. When reception of write data has been completed, the rewrite target ECU  19  transmits a receipt completion notification indicating that the reception of the write data has been completed to the CGW  13 , and, when writing of the write data has been completed, the rewrite target ECU transmits a write completion notification indicating that the writing of the write data has been completed to the CGW  13 . 
     The first distribution aspect will be described with reference to  FIG. 93 . When a divided file is acquired from the DCM  12 , the CGW  13  distributes the acquired divided file as write data to the rewrite target ECU  19 . When reception of the write data has been completed, the rewrite target ECU  19  transmits a receipt completion notification to the CGW  13  and initiates a write process on the write data. When the receipt completion notification of the write data is received from the rewrite target ECU  19 , the CGW  13  transmits a transfer request to the DCM  12  and requests the DCM  12  to transfer the next divided file. When the next divided file is acquired from the DCM  12 , the CGW  13  distributes the acquired next divided file as write data to the rewrite target ECU  19 . 
     As described above, in the first distribution aspect, the CGW  13  acquires the next write data from the DCM  12  and distributes the next write data to the rewrite target ECU  19  without waiting for completion of writing of the write data in the rewrite target ECU  19 . Thus, in the first distribution aspect, in the CGW  13 , in a case where the rewrite target ECU  19  has not completed writing of the write data, there is concern that the next write data may not be received by the rewrite target ECU  19  even though the next divided file is acquired from the DCM  12  and the next write data is distributed to the rewrite target ECU  19 . However, in a case where the rewrite target ECU  19  has completed writing of the write data, the next divided file can be quickly acquired from the DCM  12  and the next write data can be quickly distributed to the rewrite target ECU  19 . 
     The second distribution aspect will be described with reference to  FIG. 94 . When a divided file is acquired from the DCM  12 , the CGW  13  distributes the acquired divided file as write data to the rewrite target ECU  19 . When reception of the write data has been completed, the rewrite target ECU  19  transmits a receipt completion notification to the CGW  13  and initiates a write process on the write data. When writing has been completed, the rewrite target ECU  19  transmits a write completion notification to the CGW  13 . When the write completion notification is received from the rewrite target ECU  19 , the CGW  13  transmits a transfer request to the DCM  12  and requests the DCM  12  to transfer the next divided file. When the next divided file is acquired from the DCM  12 , the CGW  13  distributes the acquired next divided file as write data to the rewrite target ECU  19 . 
     As described above, in the second distribution aspect, the CGW  13  waits for completion of writing of the write data in the rewrite target ECU  19 , then acquires the next write data from the DCM  12 , and distributes the next write data to the rewrite target ECU  19 . Thus, in the second distribution aspect, it takes time for the CGW  13  to acquire the next divided file from the DCM  12 , but it is possible to request the DCM  12  to transfer a divided file in a state in which the rewrite target ECU  19  has completed writing of write data. Therefore, when the next divided file is acquired from the DCM  12  and the next write data is distributed to the rewrite target ECU  19 , the next write data can be reliably distributed to the rewrite target ECU  19 . 
     The CGW  13  distributes write data to the rewrite target ECU  19  according to SID  34   36 , and  37 , and there are a first distribution aspect and a second distribution aspect as aspects of distributing the write data to the rewrite target ECU  19 . In the first distribution aspect, as illustrated in  FIG. 95 , the CGW  13  divides write data to be distributed by a predetermined data amount (for example, 1 k bytes), and distributes the divided write data. In the second distribution aspect, as illustrated in  FIG. 96 , the CGW  13  collectively distributes write data to be distributed without dividing the write data. The CGW  13  selects either the first distribution aspect or the second distribution aspect according to SID  34  to be distributed first to the rewrite target ECU  19 . As illustrated in  FIG. 97 , the CGW  13  specifies reception of write data in the rewrite target ECU  19  by receiving ACK (SID  74 ) for SID  37  to be finally distributed to the rewrite target ECU  19 . ACK for this SID  37  corresponds to the receipt completion notification of the write data described above with reference to  FIGS. 93 and 94 . That is, in the first distribution aspect, when ACK for SID  37  to be finally distributed to the rewrite target ECU  19  is received, the CGW  13  increments an address of the next write data to distribute the next write data to the rewrite target ECU  19  and also to further acquire the next write data from the DCM  12 . 
     Although an address and a file are correlated with each other in the DCM rewrite specification data, as a method of correlating an address with a file, for example, a folder configuration may be devised, specification data may be stored and managed in a folder 1, a file  1  may be stored and managed in a folder 2, a file  2  may be stored and managed in a folder 3, and the files may be managed in an order of file names. For example, in unpackaging illustrated in  FIG. 10 , the DCM rewrite specification data and the CGW rewrite specification data are stored and managed in the folder 1, the authenticator and the difference data of the ECU (ID 1 ) are stored and managed in the folder 2, and the authenticator and the difference data of the ECU (ID 2 ) are stored and managed in the folder 3. 
     For example, in a case where distribution of write data to the rewrite target ECU  19  is stopped for some reason such as communication disruption, the CGW  13  acquires information that can specify an address at which writing of the write data has been completed from the rewrite target ECU  19 , and requests the DCM  12  to transfer a divided file including the write data from a time point at which writing thereof is not completed. Alternatively, the CGW  13  may request the DCM  12  to transfer a divided file including write data from the beginning. 
     As described above, the CGW  13  performs the file transfer control process, thus specifies a file including write data to be written to the rewrite target ECU  19  as a transfer target file, specifies an address for acquiring the transfer target file and the first data size, requests the DCM  12  to transfer a divided file, and distributes the write data to the rewrite target ECU when the divided file is transferred from the DCM  12 . Transfer of write data from the DCM  12  to the CGW  13  and distribution of the write data from the CGW  13  to the rewrite target ECU  19  can be efficiently performed. 
     (11) Write Data Distribution Control Process 
     The write data distribution control process will be described with reference to  FIGS. 98 to 108 . The vehicle program rewriting system  1  performs the write data distribution control process in the CGW  13 . Since the CGW  13  transmits write data to the ECU  19  via the bus in the vehicle, the write data distribution control process is performed such that a bus load during distribution of the write data does not become unnecessarily high. 
     As illustrated in  FIG. 98 , a case is assumed in which the +B power ECU, the ACC ECU, and the IG ECU are connected to the same bus. In this case, in the +B power supply state, since only the +B power ECU is started, and the ACC ECU and the IG ECU are stopped, vehicle control data of only the +B power ECU is transmitted to the bus. In the ACC power supply state, since the +B power ECU and the ACC ECU are started, and the IG ECU is stopped, vehicle control data of the +B power ECU and the ACC ECU is transmitted to the bus. In the IG power supply state, since the +B power ECU, the ACC ECU, and the IG ECU are started, vehicle control data of the +B power ECU, the ACC ECU, and the IG ECU is transmitted to the bus. That is, a transmission amount of the vehicle control data decreases in an order of the IG power supply state, the ACC power supply state, and the +B power supply state. 
     As illustrated in  FIG. 99 , the CGW  13  includes a first correspondence relationship specifying unit  83   a , a second correspondence relationship specifying unit  83   b , an allowable transmission amount specifying unit  83   c , a distribution frequency specifying unit  83   d , a bus load measurement unit  83   e , and a distribution control unit  83   f  in the write data distribution control unit  83 . 
     The first correspondence relationship specifying unit  83   a  specifies a first correspondence relationship indicating a relationship between a power supply state and an allowable transmission amount for a bus on the basis of an analysis result of rewrite specification data, and specifies a bus load table illustrated in  FIG. 100 . The allowable transmission amount is a value of a transmission amount at which data can be transmitted and received under a situation in which data collision or delay does not occur. The bus load table is a table indicating a correspondence relationship between the power supply state and an allowable transmission amount for a bus, and is defined for each bus. The allowable transmission amount is a sum of a transmission amount of vehicle control data and write data that can be transmitted with respect to the maximum allowable transmission amount. 
     In the example illustrated in  FIG. 100 , since an allowable transmission amount is “80%” with respect to the maximum allowable transmission amount for the first bus, in the IG power supply state, the CGW  13  allows “50%” with respect to the maximum allowable transmission amount as an allowable transmission amount of vehicle control data and “30%” with respect to the maximum allowable transmission amount as an allowable transmission amount of write data. For the first bus, in the ACC power supply state, the CGW  13  allows “30%” with respect to the maximum allowable transmission amount as an allowable transmission amount of the vehicle control data and “50%” with respect to the maximum allowable transmission amount as an allowable transmission amount of the write data. For the first bus, in the +B power supply state, the CGW  13  allows “20%” with respect to the maximum allowable transmission amount as an allowable transmission amount of the vehicle control data, and allows “60%” with respect to the maximum allowable transmission amount as an allowable transmission amount of the write data. As illustrated in  FIG. 100 , the second bus and the third bus are defined in the same manner. 
     The second correspondence relationship specifying unit  83   b  specifies a second correspondence relationship indicating a relationship between a bus to which the rewrite target ECU  19  belongs and a power supply system on the basis of an analysis result of rewrite specification data, and specifies a rewrite target ECU-belonging table illustrated in  FIG. 101 . The rewrite target ECU-belonging table is a table indicating a bus to which the rewrite target ECU  19  belongs and a power supply system. 
     In an example illustrated in  FIG. 101 , the CGW  13  specifies the first rewrite target ECU  19  as a +B power ECU since the first rewrite target ECU  19  is connected to the first bus and is started in any of the +B power supply state, the ACC power supply state, and the IG power supply state. The CGW  13  specifies the second rewrite target ECU  19  as an ACC ECU since the second rewrite target ECU is connected to the second bus and is stopped in the +B power supply state, but is started in the ACC power supply state and the IG power supply state. The CGW  13  specifies the third rewrite target ECU  19  as an IG ECU since the third rewrite target ECU  19  is connected to the third bus, and is stopped in the +B power supply state and the ACC power supply state, but is started in the IG power supply state. The CGW  13  uses the data of the “connection bus” and the “connection power supply” in the rewrite specification data illustrated in  FIG. 8  to specify a bus to which the rewrite target ECU  19  is connected and a power supply system corresponding thereto. When such information can be specified, the information is not necessarily required to be stored in a table form. 
     The allowable transmission amount specifying unit  83   c  specifies an allowable transmission amount for a bus to which the rewrite target ECU  19  belongs, the allowable transmission amount corresponding to a power supply states of the vehicle when a program is updated, according to the specifying result of the first correspondence relationship and the specifying result of the second correspondence relationship. Specifically, the allowable transmission amount specifying unit  83   c  specifies a bus to which the rewrite target ECU  19  belongs by using the rewrite target ECU-belonging table that is the second correspondence relationship, and specifies an allowable transmission amount in each power supply state for the specified bus by using the bus load table that is the first correspondence relationship. 
     The distribution frequency specifying unit  83   d  specifies a distribution frequency of write data corresponding to a power supply state at the time of installation, by using a predefined correspondence relationship between a power supply state and a distribution frequency of write data. Specifically, the distribution frequency specifying unit  83   d  specifies, by using the bus load table, an allowable transmission amount allocated for distributing write data among allowable transmission amounts specified by the allowable transmission amount specifying unit  83   c , and specifies a distribution frequency of the write data. For example, when it is specified that a bus to which the rewrite target ECU  19  belongs is the first bus, when a power supply state at the time of installation is the IG power supply state, the distribution frequency specifying unit  83   d  specifies an allowable transmission amount as “80%”, specifies an allowable transmission amount allocated for distributing the write data as “30%” out of 80%, and thus specifies a distribution frequency of the write data. The allowable transmission amount allocated for distributing the write data corresponds to transmission restriction information. 
     The bus load measurement unit  83   e  measures a bus load of a bus to which the rewrite target ECU  19  belongs. The bus load measurement unit  83   e  measures the bus load by counting the number of frames or the number of bits received per unit time, for example. The distribution control unit  83   f  controls distribution of the write data depending on the distribution frequency specified by the distribution frequency specifying unit  83   d.    
     Next, an operation of the write data distribution control unit  83  in the CGW  13  will be described with reference to  FIGS. 102 to 108 . The CGW  13  executes a write data distribution control program and thus performs the write data distribution control process. 
     When an unpackaging completion notification signal is received from the DCM  12 , the CGW  13  initiates the write data distribution control process. The CGW  13  acquires the CGW rewrite specification data from the DCM  12  (S 1101 ), and specifies a bus load table and a rewrite target ECU-belonging table by using the CGW rewrite specification data (S 1102 ). The CGW  13  specifies a bus to which the rewrite target ECU  19  belongs by using the rewrite target ECU-belonging table (S 1103 ). The CGW  13  specifies an allowable transmission amount for the bus to which the rewrite target ECU  19  belongs, the allowable transmission amount corresponding to a power supply state of the vehicle when update is performed by using the bus load table. The CGW  13  specifies a distribution frequency of the write data by considering the specified allowable transmission amount (S 1104 ; corresponding to a distribution frequency specifying procedure). The CGW  13  refers to the allowable transmission amount for the first bus in the IG power supply state, for example, in a case where the write data is distributed to the ECU (ID 1 ) as the first rewrite target ECU  19  while the vehicle is traveling. In the example illustrated in  FIG. 100 , the allowable transmission amount for the first bus in the IG power supply state is “80%”, out of which transmission of “50%” is allowed in the vehicle control data and transmission of “30%” is allowed in the write data. The allowable transmission amount is a value for only an example, and a numerical value is set within an allowable range in accordance with the specification of communication to be applied. 
     Since one frame is about 250 μs in the specification on 500 kbps of CAN, when interruption occurs four times for one second, four frames are generated, and a bus load is 100%. The CGW  13  specifies a distribution frequency of the write data by determining the interruption occurring in the bus. The CGW  13  initiates to measure the number of frames received in the unit time, initiates to measure a bus load (S 1105 ), determines whether or not the measured bus load exceeds the allowable transmission amount (S 1106 ), and sets a distribution interval. The distribution interval is a time interval until the CGW  13  distributes write data to the rewrite target ECU  19 , receives a write completion notification (ACK) from the rewrite target ECU  19 , and transmits the next write data to the rewrite target ECU  19 . 
     When it is determined that the measured bus load does not exceed the allowable transmission amount (S 1106 : NO), the CGW  13  sets the distribution interval of the write data to the shortest interval set in advance, and initiates to distribute the write data to the rewrite target ECU  19  as illustrated in  FIG. 103  (S 1107 ; corresponding to a distribution control procedure). That is, the CGW  13  sets the distribution interval of one frame on the CAN to the shortest interval set in advance, and initiates to distribute the write data to the rewrite target ECU  19 . One frame on the CAN includes write data having a data amount of 8 bytes. One frame on CAN with Flexible Data-Rate (CAN FD) includes write data having a data amount of 64 bytes. 
     On the other hand, when it is determined that the measured bus load exceeds the allowable transmission amount (S 1106 : YES), the CGW  13  computes an interval at which the bus load does not exceed the allowable transmission amount (S 1108 ), sets the distribution interval of the write data to the computed interval, and initiates to distribute the write data to the rewrite target ECU  19  as illustrated in  FIG. 104  (S 1109 ; corresponding to a distribution control procedure). 
     For example, in the IG power supply state, the CGW  13  determines whether or not the bus load exceeds the allowable transmission amount of “80%” for the first bus, and, when it is determined that the bus load does not exceed the allowable transmission amount, sets a distribution interval T1 at which an allowable transmission amount of the write data is “30%”. That is, as shown in the bus load table of  FIG. 100 , the CGW  13  sets the distribution interval T1 by using “30%” that is an allowable transmission amount of write data for the first bus in the IG power supply state. The CGW  13  sets the distribution interval T1 such that the maximum transmission amount is allowed. The CGW  13  may measure a bus load by narrowing a measurement target to a frame of write data, and determine whether or not the bus load depending on the write data exceeds the allowable transmission amount “30%” of the write data. When it is determined that the bus load exceeds the allowable transmission amount, the CGW  13  changes the distribution interval to a distribution interval T2 (&gt;T1) at which the bus load does not exceed the allowable transmission amount, according to the amount by which the bus load exceeds the allowable transmission amount. In above-described way, after write data is acquired from the DCM  12 , the CGW  13  waits until the set distribution interval is reached, and distributes the write data to the rewrite target ECU  19 . 
     When distribution of the write data to the rewrite target ECU  19  is initiated, the CGW  13  determines whether or not the distribution of the write data to the rewrite target ECU  19  has been completed, and continuously determines whether or not the measured bus load exceeds the allowable transmission amount (S 1110  and S 1011 ). When it is determined that the measured bus load does not exceed the allowable transmission amount (S 1111 : NO), the CGW  13  sets a distribution interval of the write data to the shortest interval set in advance, and changes the distribution interval of the write data to the rewrite target ECU  19  (S 1112 ). On the other hand, when it is determined that the measured bus load exceeds the allowable transmission amount (S 1111 : YES), the CGW  13  computes an interval at which the bus load does not exceed the allowable transmission amount (S 1113 ), sets a distribution interval of the write data to the computed interval, and changes the distribution interval of the write data to the rewrite target ECU  19  (S 1114 ). 
     When it is determined that the distribution of the write data to the rewrite target ECU  19  has been completed (S 1110 : YES), the CGW  13  stops measuring the number of frames received per unit time, stops measuring the bus load (S 1115 ), and finishes the write data distribution control process. Here, in a case where there are a plurality of the rewrite target ECUs  19 , the CGW  13  performs the write data distribution control process on installation in all of the rewrite target ECUs  19 . 
     As described above, the CGW  13  performs the write data distribution control process, thus specifies a distribution frequency of write data to the rewrite target ECU  19  by using a correspondence relationship between a predetermined power supply state and a distribution frequency of write data, and controls distribution of the write data according to the distribution frequency. It is possible to reduce, for example, data collision or delay during installation. Distribution of write data can coexist without hindering distribution of vehicle control data on the same bus. 
     In the above description, the configuration has been exemplified in which the bus load table is specified on the basis of an analysis result of the rewrite specification data in the CGW  13 , but the bus load table may be stored in advance. The configuration has been exemplified in which the rewrite target ECU-belonging table is specified on the basis of an analysis result of the rewrite specification data in the CGW  13 , but the rewrite target ECU-belonging table may be stored in advance. 
     In a power supply state in which the vehicle is traveling, a distribution amount of write data may be relatively reduced, and, in a power supply state in which the vehicle is parked, the distribution amount of the write data may be relatively increased. That is, in the CGW  13 , as illustrated in  FIG. 105 , when the IG power is in an ON state while the vehicle is traveling, the IG ECU, the ACC ECU, and the +B power ECU transmit a CAN frame, so that a transmission amount of application data such as vehicle control or diagnosis becomes relatively large, and thus a distribution amount of write data is relatively reduced. In the CGW  13 , as illustrated in  FIG. 106 , when the IG power is in an OFF state while the vehicle is parked, only the +B power ECU transmits a CAN frame, so that a transmission amount of application data such as vehicle control or diagnosis becomes relatively small, and thus a distribution amount of write data is relatively increased. That is, the CGW  13  adjusts a distribution amount of write data within a free capacity that does not hinder transmission of application data such as vehicle control or diagnosis. 
     As illustrated in  FIG. 107 , in the CGW  13 , in a case where an event frame is transmitted from the rewrite target ECU  19 , since the frequency of interruption increases by receiving the event frame, and thus a bus load increases, a distribution amount of write data may be relatively reduced, and, in a case where the event frame is no longer transmitted from the rewrite target ECU  19 , the distribution amount of the write data may be relatively increased. 
     As illustrated in  FIG. 108 , in the vehicle system, in a case where it is specified that the CGW  13  is distributing write data, a bus load may be reduced by increasing a transmission interval of application data such as vehicle control or diagnosis to the allowable maximum interval. In the CGW  13 , since the bus load is reduced by the vehicle system increasing the transmission interval of the application data, a distribution amount of write data may be relatively increased. 
     The bus load table incorporated in the rewrite specification data is set uniformly and commonly by, for example, a vehicle manufacturer regardless of a vehicle model, grade, or the like. This is because, for example, when equipment of an ECU greatly changes depending on the vehicle model, grade, or the like, a bus load greatly changes, and, when the optimum bus load table is individually set depending on the vehicle model, grade, or the like, complicated labor such as labor to verify the bus load table is required, so that such complicated labor is reduced. 
     As described above, similarly to the case where installation is performed while the vehicle is traveling, also in a case where installation is performed while the vehicle is parked, the write data distribution control process is performed. When the rewrite target ECU  19  is a +B power ECU, update can be performed in the +B power supply state, and thus an allowable transmission amount in the +B power supply state in the bus load table is referred to. On the other hand, in a case where the rewrite target ECU  19  is an IG ECU, installation is performed in the IG power supply state, and thus an allowable transmission amount in the IG power supply state in the bus load table is referred to. Here, for example, in a case where the rewrite target ECU  19  is an ACC ECU, installation can be performed in the IG power supply state. In this case, an allowable transmission amount in the IG power supply state in the bus load table is referred to. The configuration of storing the bus load table and the rewrite target ECU-belonging table has been described, but any table may be stored as long as a distribution frequency of write data in each power supply state can be specified. 
     (12) Activation Request Instruction Process 
     The activation request instruction process will be described with reference to  FIGS. 109 to 111 . The vehicle program rewriting system  1  performs an activation request instruction process in the CGW  13 . The CGW  13  makes activation requests to a plurality of rewrite target ECUs  19  in which rewriting of an application program has been completed in order to validate the rewritten program. In the present embodiment, a state is assumed in which the CGW  13  analyzes the CGW rewrite specification data to recognize a group of the rewrite target ECUs  19 . The CGW  13  makes an activation request only during parking, and does not make an activation request during traveling of the vehicle. 
     As illustrated in  FIG. 109 , the CGW  13  includes a rewrite target specifying unit  84   a , a rewrite completion determination unit  84   b , an activation executability determination unit  84   c , and an activation request instruction unit  84   d  in the activation request instruction unit  84 . The rewrite target specifying unit  84   a  specifies a plurality of rewrite target ECUs  19  among a plurality of rewrite target ECUs  19  performing cooperative control. When the plurality of rewrite target ECUs  19  are specified by the rewrite target specifying unit  84   a , the rewrite completion determination unit  84   b  determines whether or not rewriting of programs has been completed in all of the plurality of specified rewrite target ECUs  19 . 
     When it is determined by the rewrite completion determination unit  84   b  that the rewriting of the programs has been completed in all of the plurality of rewrite target ECUs  19 , the activation executability determination unit  84   c  determines whether or not activation is executable. The activation executability determination unit  84   c  determines that the activation is executable in a case where the activation is approved by the user and the vehicle is in a parking state. 
     The activation request instruction unit  84   d  gives an instruction for an activation request in a case where it is determined by the activation executability determination unit  84   c  that the activation is executable. Specifically, the activation request instruction unit  84   d  gives the instruction for the activation request by giving an instruction for a reset request, monitoring session transition timeout, or monitoring the internal reset of the rewrite target ECU  19  after giving an instruction for a request for switching to a new bank. In a double-bank memory ECU or a single-bank suspend memory ECU, an application program is activated by starting the application program on a new bank (inactive bank) in which the application program is written. On the other hand, in a single-bank memory ECU, the application program is activated through restart. The rewrite target ECU  19  may be configured to be reset by itself regardless of an activation request after an instruction for a request for switching to a new bank is received. 
     Next, with reference to  FIGS. 110 and 111 , an operation of the activation request instruction unit in the CGW  13  will be described. The CGW  13  executes an activation request instruction program and thus performs the activation request instruction process. 
     When the activation request instruction process is initiated, the CGW  13  specifies a plurality of rewrite target ECUs  19  (S 1201 ; corresponding to a rewrite target specifying procedure). Specifically, the CGW  13  specifies the rewrite target ECUs  19  by referring to ECUs (IDs) described in the rewrite specification data. The CGW  13  determines whether or not rewriting of application programs has been completed in all of the plurality of specified rewrite target ECUs  19  (S 1202 ; corresponding to a rewrite completion determination procedure). For example, the CGW  13  sequentially performs installation on the rewrite target ECUs  19  according to the order of the ECUs (IDs) described in the rewrite specification data, and determines that writing has been completed in all of the rewrite target ECUs  19  when installation for an ECU (ID) described last has been completed. 
     When it is determined that rewriting of the application program has been completed in all of the plurality of specified rewrite target ECUs  19  (S 1202 : YES), the CGW  13  determines whether or not activation is executable (S 1203 ; corresponding to an activation executability determination procedure). Specifically, the CGW  13  determines whether or not the user&#39;s approval for the update has been obtained so far, whether or not the vehicle is in a parking state, and the like, and determines that the activation is executable when these conditions are satisfied. The user&#39;s approval may be an approval for the entire update process or an approval for the activation. When it is determined that activation is executable (S 1203 : YES), the CGW  13  subsequently gives instructions for activation requests to the plurality of rewrite target ECUs  19  at the same time (corresponding to an activation request instruction procedure). Here, a description will be made assuming that the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ) are the rewrite target ECUs  19  of the same group. 
     When it is determined that activation is executable for the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ), the CGW  13  initiates the activation request instruction process. When the activation request instruction process is initiated, the CGW  13  gives an instruction for a request for switching to a new bank to the rewrite target ECU  19  (S 1204 ). The CGW  13  requests the power supply management ECU  20  to switch on the IG power in an OFF state (S 1205 ). The CGW  13  switches on the IG power in an OFF state in order to perform activation although the vehicle is in a parking state and the IG switch  42  is in an OFF state. In a case where the CGW  13  performs installation and subsequently performs activation, since the IG power is in an ON state, S 1205  is not performed, and a start request (wake-up request) is made to the rewrite target ECU  19  in the sleep state. 
     The CGW  13  transmits a software reset request to the rewrite target ECU  19 , and gives an instruction for the software reset request to the rewrite target ECU  19  (S 1206 ). In a case where the rewrite target ECU  19  has a specification of coping with the software reset request, when the software reset request is received from the CGW  13 , the rewrite target ECU  19  is restarted by resetting the software, and activates an application program. In a case where the rewrite target ECU  19  is a single-bank memory ECU, the rewrite target ECU  19  is restarted by the new application program and thus switches from the old application program to the new application program. In a case where the rewrite target ECU  19  is a single-bank suspend memory ECU or a double-bank memory ECU, the rewrite target ECU  19  updates the active bank information (the bank-A or the bank-B) stored in the flash memory, causes a bank to which the new application program is written to switch to an active bank, and thus switches from the old application program to the new application program. 
     The CGW  13  requests the power supply management ECU  20  to switch off the IG power in an ON state and to switch on the IG power in an OFF state, gives an instruction for a power reset request to the rewrite target ECU  19 , and instructs the rewrite target ECU  19  to be restarted (S 1207 ). Even in a case where the rewrite target ECU  19  does not have a specification of coping with the software reset request, when the IG power switches from an ON state to an OFF state and the IG power switches from an OFF state to an ON state, the rewrite target ECU is reset and restarted to activate the application program. Also in this case, in a case where the rewrite target ECU  19  is a single-bank memory ECU, the rewrite target ECU  19  is restarted by the new application program and thus switches from the old application program to the new application program. In a case where the rewrite target ECU  19  is a single-bank suspend memory ECU or a double-bank memory ECU, the rewrite target ECU  19  updates the active bank information (the bank-A or the bank-B) stored in the flash memory, causes a bank to which the new application program is written to switch to an active bank, and thus switches from the old application program to the new application program. The CGW  13  monitors session transition timeout (S 1208 ) and monitors the internal reset of the rewrite target ECU  19  (S 1209 ). 
     That is, in a case where the rewrite target ECU  19  does not have the specification of coping with the software reset request, the CGW  13  cannot give an instruction for activation even when the software reset request is transmitted to the rewrite target ECU  19 . Therefore, an instruction for the power reset request is given to the rewrite target ECU  19 , and thus activation is performed in the rewrite target ECU  19  that does not have the specification of coping with the software reset request. For example, an IG ECU such as an engine ECU is configured to be reset without fail when the power is turned on or off, and, thus, in many cases, a configuration does not cope with the software reset request. From the viewpoint of the rewrite target ECU  19 , activation is performed (started by the new program) by any of reception of an instruction for the software reset request from the CGW  13 , reception of an instruction for the power reset request from the CGW  13 , the session transition timeout, and the internal reset. 
     When an instruction for the software reset request is received from the CGW  13 , the rewrite target ECU  19  coping with the software reset request is forced to be reset to perform activation. The rewrite target ECU  19  that is an ACC ECU or an IG ECU is reset to perform activation when power is supplied next since the power is forced not to be supplied in a case where an instruction for the power reset request is received from the CGW  13 . Unlike the rewrite target ECU  19  that is an ACC or IG ECU, the rewrite target ECU  19  that is a +B power ECU is supplied with power at all times, and thus activation is performed by the session transition timeout or the internal reset. An activation method for each rewrite target ECU  19  is specified by the rewrite specification data. 
     When the CGW  13  is notified that the new application program is normally started from all of the rewrite target ECUs  19 , the CGW transmits a switching completion notification to the DCM  12  (S 1210 ). The DCM  12  notifies the center device  3  that activation of the update programs has been completed. The CGW  13  requests the power supply management ECU  20  to switch on the IG power in an OFF state, and finishes an application program activation synchronization instruction process. When the IG power switches from an OFF state to an ON state through the user operation, the CGW  13  transmits a program version, an active bank, and the like of the ECU to the DCM  12 . The DCM  12  notifies the center device  3  of the information of each ECU  19  received from the CGW  13 . Here, when the DCM  12  notifies the center device  3  of completion of the activation, ECU configuration information including a program version and bank information of each ECU may be transmitted to the center device  3 .  FIG. 111  illustrates a case where the rewrite target ECU  19  is a double-bank memory ECU or a single-bank suspend memory ECU. 
     As described above, the CGW  13  performs the activation request instruction process, thus prevents a situation in which a plurality of rewrite target ECUs  19  having completed rewriting of application programs switch from old programs to new programs at their own timings, and appropriately aligns timings of switching from the old programs to the new programs in the plurality of rewrite target ECUs  19 . That is, a situation is prevented in which program versions of a plurality of rewrite target ECUs  19  which cooperate with each other do not match each other, and thus a problem occurs in a cooperative process. 
     (13) Activation Execution Control Process 
     The activation execution control process will be described with reference to  FIGS. 112 to 114 . The activation execution control process is a process performed by the rewrite target ECU  19  to which an instruction for an activation request is given by the CGW  13  due to the CGW  13  performing (12) the activation request instruction process described above. The vehicle program rewriting system  1  performs the activation execution control process in the rewrite target ECU  19 . Here, the rewrite target ECU  19  has a plurality of data storage banks, such as a single-bank suspend memory or a double-bank memory. A state is assumed in which the rewrite target ECU  19  has a first data storage bank and a second data storage bank, and installation of rewrite data has been completed in an inactive bank (new bank). 
     As illustrated in  FIG. 112 , the ECU  19  includes an active bank information update unit  107   a , an execution condition determination unit  107   b , an execution control unit  107   c , and a notification unit  107   d  in the activation execution control unit  107 . When an instruction for an activation request is received from the CGW  13 , the active bank information update unit  107   a  updates active bank determination information (active bank information) of the flash memory in preparation for the next restart. For example, when the bank-A is currently active and a new program is written in the bank-B, the active bank information update unit  107   a  updates the active bank information from the bank-A to the bank-B. 
     The execution condition determination unit  107   b  determines whether or not an instruction for a software reset request is received from the CGW  13 , whether or not an instruction for a power reset request is given from the CGW  13  to the power supply management ECU  20 , and whether or not disruption of communication with the CGW  13  lasts for a predetermined time, as activation execution conditions. When any one of the conditions is satisfied, the execution condition determination unit  107   b  determines that the activation execution conditions are established. Whether or not an instruction for the power reset request is received may be detected by the power detection circuit  36  instead of an instruction from the CGW  13 . When it is determined by the execution condition determination unit  107   b  that the activation execution condition is established, the execution control unit  107   c  performs new bank switching (activation) of causing the active bank to switch from the old bank (the bank currently operated) to the new bank (the bank not currently operated) in accordance with the active bank information. The notification unit  107   d  notifies the CGW  13  of notification information such as active bank information and version information. 
     Next, an operation of the activation execution control unit  107  in the rewrite target ECU  19  will be described with reference to  FIGS. 113 and 114 . The rewrite target ECU  19  executes an activation execution control program and thus performs the activation execution control process. 
     (13-1) Rewrite Process 
     When the rewrite process is initiated, the rewrite target ECU  19  performs processes up to immediately before memory erasure, such as part number reading or authenticating as a pre-rewrite process (S 1301 ). The rewrite target ECU  19  determines whether or not rewrite bank information has been received from the center device  3  (S 1302 ). The rewrite target ECU  19  determines whether or not the rewrite bank information has been received on the basis of, for example, whether or not the rewrite bank information described in rewrite specification data included in a distribution package has been acquired from the CGW  13 . When it is determined that the rewrite bank information has been received from the center device  3  (S 1302 : YES), the rewrite target ECU  19  collates the rewrite bank information with rewrite bank information (active bank information) managed thereby, and thus determines whether or not the two pieces of information match each other (S 1303 ). Here, the rewrite bank information is described in the rewrite specification data transmitted from, for example, the center device  3 . For example, in a case where the rewrite bank information managed by the rewrite target ECU indicates that an active bank is the bank-A and an inactive bank is the bank-B, when the rewrite bank information described in the rewrite specification data indicates the inactive bank (bank-B), it is determined that both of the pieces of information match each other, and, when the rewrite bank information described in the specification data indicates the active bank (bank-A), it is determined that both of the pieces of information do not match each other. 
     When it is determined that both of the pieces of information match each other (S 1303 : YES), the rewrite target ECU  19  performs, as the rewrite process, memory erasure, writing of write data, and verification (S 1304 ), and finishes the rewrite process. The verification is, for example, to verify the integrity of data written in the flash memory. When it is determined that both of the pieces of information do not match each other (S 1303 : NO), the rewrite target ECU  19  transmits a negative acknowledgement to the CGW  13  (S 1305 ), and finishes the rewrite process. 
     (13-2) Activation Execution Control Process 
     When the activation execution control process is initiated, the rewrite target ECU  19  sets an inactive bank as a rewrite bank, and determines whether or not rewriting of an application program into the rewrite bank has been completed (S 1311 ). When it is determined that rewriting of the application program into the rewrite bank has been completed (S 1311 : YES), the rewrite target ECU  19  verifies the integrity of the application program written in the flash memory, and determines whether or not data verification after the rewriting is positive (S 1312 ). When it is determined that the data verification after the rewriting is positive (S 1312 : YES), the rewrite target ECU  19  sets a rewrite completion flag of the new bank to “OK” and stores the rewrite completion flag (S 1313 ). 
     Thereafter, the rewrite target ECU  19  determines whether or not an instruction for an activation request has been received from the CGW  13  (S 1314 ). When it is determined that the instruction for the activation request has been received (S 1314 : YES), the rewrite target ECU  19  determines whether or not the rewrite completion flag of the new bank is “OK” (S 1315 ), and updates the active bank information when it is determined that the rewrite completion flag of the new bank is “OK” (S 1315 : YES) (S 1316 ; corresponding to an active bank information update procedure). That is, for example, in a case where an active bank is the bank-A and an inactive bank is the bank-B, when rewriting of the application program into the rewrite bank has been completed by using the bank-B as the rewrite bank, the rewrite target ECU  19  updates the active bank information indicating that an active bank is the bank-A and an inactive bank is the bank-B to active bank information indicating that an active bank is the bank-B and an inactive bank is the bank-A. 
     When the active bank information is updated, the rewrite target ECU  19  determines whether or not a software reset request has been received from the CGW  13 , whether or not an instruction for a power reset request has been given from the CGW  13  to the power supply management ECU  20 , and whether or not disruption of communication with the CGW  13  lasts for a predetermined time after the instruction for the software reset request is received, and thus determines whether or not the activation execution condition is established (S 1317 ; corresponding to an execution condition determination procedure). Here, the rewrite target ECU  19  is restarted when any of the activation execution conditions is established, and restart conditions are defined for each ECU. 
     The rewrite target ECU  19  determines whether an instruction for the software reset request has been received from the CGW  13 , the instruction for the power reset request has been given from the CGW  13  to the power supply management ECU  20 , or the predetermined time has elapsed after the instruction for the software reset request is received, and executes restart (reset) when it is determined that the activation execution condition is established (S 1317 : YES). The rewrite target ECU  19  executes the restart and is started by using the new bank (bank-B) as an active bank (S 1318 ; corresponding to an activation control procedure) according to the updated active bank information, and finishes the activation execution control process. That is, after the rewrite target ECU  19  is restarted, the rewrite target ECU is started in the bank-B in which the application program is installed. 
     When it is determined that rewriting of the application program to the new bank is not completed (S 1311 : NO), or it is determined that the data verification after the rewriting is negative (S 1312 : NO), the rewrite target ECU  19  determines whether or not an instruction for an activation request has been received (S 1319 ), transmits a negative acknowledgement to the CGW  13  (S 1320 ) when it is determined that the instruction for the activation request has been received (S 1319 : YES), and returns to step S 1311 . When it is determined that the data verification after the rewriting is negative, the rewrite target ECU  19  may finish the activation execution control process and perform a process such as rollback. When it is determined that the rewrite completion flag of the new bank is not “OK” (S 1315 : NO), the rewrite target ECU  19  transmits a negative acknowledgement to the CGW  13  (S 1321 ) and returns to step S 1311 . 
     As described above, the rewrite target ECU  19  performs the activation execution control process, thus updates the active bank information in preparation for the next restart when an instruction for an activation request is received from the CGW  13 , and performs new bank switching for causing an active bank to switch from the old bank to the new bank according to the active bank information after restarting when the activation execution condition is established. That is, the rewrite target ECU  19  is not started by an update program unless the CGW  13  gives an instruction for activation thereto even though installation of the update program has been completed. For example, even when the rewrite target ECU  19  is restarted due to the user turning on the IG switch  42  in an OFF state, unless an instruction for activation is received from the CGW  13 , the rewrite target ECU is started with the same active bank. The CGW  13  simultaneously gives instructions for activation to a plurality of rewrite target ECUs  19 , and then update programs of the plurality of the rewrite target ECUs  19  can be simultaneously validated when being restarted by software reset, power reset, or session timeout. In the above description, the case where data storage banks are double banks has been described, but the same applies to a case where data storage banks are three or more banks. 
     In the activation request instruction process (12) in the CGW  13 , the CGW  13  performs the activation request instruction process on a plurality of rewrite target ECUs  19  having completed rewriting of application programs, and thus it is possible to prevent a situation in which the plurality of rewrite target ECUs  19  having completed rewriting of the application programs switch from old programs to new programs at their own timings, and to appropriately align timings of switching from the old programs to the new programs in the plurality of rewrite target ECUs  19 . 
     (14) Rewrite Target Group Management Process 
     The rewrite target group management process will be described with reference to  FIGS. 115 to 118 . The vehicle program rewriting system  1  performs the rewrite target group management process in the CGW  13 . The CGW  13  simultaneously instructs one or more rewrite target ECUs  19  belonging to the same group to activate application programs. The CGW  13  performs control from installation to activation in the group unit. Here, a description will be made assuming that the ECU (ID 1 ) and the ECU (ID 2 ) are the rewrite target ECUs  19  of a first group, and an ECU (ID 11 ), an ECU (ID 12 ), and an ECU (ID 13 ) are the rewrite target ECUs  19  of a second group. 
     As illustrated in  FIG. 115 , the CGW  13  includes a group generation unit  85   a  and an instruction execution unit  85   b  in the rewrite target group management unit  85 . The group generation unit  85   a  groups the rewrite target ECUs  19  to be upgraded together according to an analysis result of the CGW rewrite specification data, and thus generates a group. In a case where the group is generated by the group generation unit  85   a , the instruction execution unit  85   b  gives an instruction for installation in a predetermined order in the unit of the group, and gives an instruction for activation in the unit of group when the installation has been completed. 
     Next, with reference to  FIGS. 116 to 118 , an operation of the rewrite target group management unit  85  in the CGW  13  will be described. The CGW  13  executes a rewrite target grouping program and thus performs the rewrite target group management process. When the rewrite target group management process is initiated, the CGW  13  acquires the CGW rewrite specification data from the DCM  12  (S 1401 ; corresponding to a rewrite specification data acquisition procedure), analyzes the acquired rewrite specification data (S 1402 ; corresponding to a rewrite specification data analysis procedure), and determines a group to which the present rewrite target ECU  19  belongs. For example, the CGW  13  may specify to which group the rewrite target ECU belongs by referring to information regarding the ECU of the rewrite specification data, and may specify to which group the ECU belongs by referring to information regarding the group of the rewrite specification data. The CGW  13  determines whether or not the rewrite target ECU  19  is initially subjected to rewriting for a certain group (S 1403 ), determines whether or not the rewrite target ECU  19  belonging to the same group as that of the previous rewrite target ECU  19  is subjected to rewriting (S 1404 ), and determines whether or not the rewrite target ECU  19  belonging to a group different from that of the previous rewrite target ECU  19  is subjected to rewriting (S 1405 ; corresponding to a group generation procedure). 
     When it is determined that the rewrite target ECU  19  is initially subjected to rewriting (S 1403 : YES) or it is determined that the rewrite target ECU  19  belonging to the same group as that of the previous rewrite target ECU  19  is subjected to rewriting (S 1404 : YES), the CGW  13  instructs the rewrite target ECU  19  to rewrite an application program such that the application program of the rewrite target ECU  19  is rewritten (S 1406 ). The CGW  13  determines whether or not there is the next rewrite target ECU  19  (S 1407 ). When it is determined that there is the next rewrite target ECU  19  in the same group (S 1407 : YES), the CGW  13  returns to the above steps S 1403  to S 1405 , and repeatedly performs S 1403  to S 1405 . 
     When it is determined that the rewrite target ECU  19  belonging to a group different from that of the previous rewrite target ECU  19  is subjected to rewriting (S 1405 : YES), the CGW  13  proceeds to an activation request instruction process (S 1408 ; corresponding to an instruction execution procedure). 
     When the activation request instruction process is initiated, the CGW  13  determines whether or not there is the next rewrite target ECU  19  (S 1411 ). That is, the CGW  13  determines whether or not there is a group in which installation is not completed. When it is determined that there is the next the rewrite target ECU  19  (S 1411 : YES), the CGW  13  gives an instruction for an activation request to the rewrite target ECU  19  belonging to the group in which the rewriting has been completed (S 1412 ). That is, in a case where installation has not yet been performed on the rewrite target ECU  19  belonging to the second group, the CGW  13  gives an instruction for activation to the rewrite target ECU (ID 1 ) and the rewrite target ECU (ID 2 ) of the first group in which rewriting is already completed. 
     The CGW  13  gives an instruction for a software reset request to the rewrite target ECU  19 , and instructs the rewrite target ECU  19  to be restarted by switching on the power in an OFF state and switching off the power in an ON state via the power supply management ECU  20 , and thus the application programs of the rewrite target ECU (ID 1 ) and the rewrite target ECU (ID 2 ) are started together. 
     The CGW  13  determines a rewrite timing for the next rewrite target ECU  19  (S 1413  and S 1314 ). That is, the CGW  13  determines rewrite timings for the rewrite target ECUs  19  belonging to the second group. When it is determined that the rewrite timing for the next rewrite target ECU  19  is a timing of the user&#39;s switching from the next riding to getting-off (S 1413 : YES), the CGW  13  switches off the IG power in an ON state (S 1415 ), finishes the activation request instruction process, and the returns to the rewrite target group management process. For example, when a time period in which rewriting of an application program is allowed to be updated is set by the user in advance, and it is predicted that installation in the rewrite target ECU  19  belonging to the second group is not completed during the time period, the CGW  13  performs installation in the next parking state. In this case, the CGW  13  instructs the power supply management ECU  20  to turn off the IG power in order to return to the original parking state. 
     When it is determined that the rewrite timing for the next rewrite target ECU  19  is the present getting-off (parking state) (S 1414 : YES), the CGW  13  determines whether or not a remaining battery charge of the vehicle battery  40  is equal to or more than a threshold value (S 1417 ). Here, the threshold value may be a value set in advance or a value acquired from CGW rewrite specification data. When it is determined that the remaining battery charge of the vehicle battery  40  is not equal to or more than the threshold value (S 1416 : NO), the CGW  13  instructs the power supply management ECU  20  to switch off the IG power in an ON state (S 1415 ), finishes the activation request instruction process, and returns to the rewrite target group management process. When it is determined that the remaining battery charge of the vehicle battery  40  is equal to or more than the threshold value (S 1416 : YES), the CGW  13  maintains the IG power to be in an ON state (S 1417 ), finishes the activation request instruction process, and returns to the rewrite target group management process. As illustrated in  FIG. 116 , the CGW  13  rewrites the application program of the rewrite target ECU  19  belonging to the second group. 
     When it is determined that there is no next rewrite target ECU  19  (S 1411 : NO), the CGW  13  gives an instruction for an activation request to the rewrite target ECU  19  belonging to the group in which rewriting has been completed (S 1418 ), switches off the IG power in an ON state (S 1419 ), finishes the instruction process of the activation request, and returns to the group management process of the rewrite target. For example, when rewriting in the rewrite targets ECU (ID 11 ), ECU (ID 12 ), and ECU (ID 13 ) belonging to the second group has been completed, the next rewrite target ECU  19 , that is, the next group is not present. In this case, the CGW  13  instructs the ECU (ID 11 ), the ECU (ID 12 ), and the ECU (ID 12 ) to activate the update programs, and instructs the power supply management ECU  20  to turn off the IG power after the activation has been completed. 
     As illustrated in  FIG. 118 , in a case where the application programs of the ECU (ID 1 ) and the ECU (ID 2 ) and the ECU (ID 11 ) to the ECU (ID 13 ) are rewritten, when the ECU (ID 1 ) and ECU (ID 2 ) have a cooperative control relationship, and the ECU (ID 11 ), the ECU (ID 12 ), and the ECU (ID 13 ) have a cooperative control relationship, in a distribution package, the ECU (ID 1 ) and the ECU (ID 2 ) belong to the first group as the rewrite target ECUs  19 , and the ECU (ID 11 ), the ECU (ID 12 ), and the ECU (ID 13 ) belong to the second group as the rewrite target ECUs  19 . When rewriting of the application programs has been completed in the ECU (ID 1 ) and the ECU (ID 2 ) belonging to the first group, the CGW  13  simultaneously gives an instruction for an activation request to the ECU (ID 1 ) and the ECU (ID 2 ). Thereafter, the CGW  13  executes rewriting of the application programs in the ECU (ID 11 ), the ECU (ID 12 ), and the ECU (ID 13 ) belonging to the second group, and gives an instruction for an activation request to the ECU (ID 11 ), the ECU (ID 12 ), and the ECU (ID 13 ) when the rewriting has been completed in all of the ECUs. The rewrite target ECU  19  that is a single-bank memory is instructed to be restarted, and is thus instructed to perform activation. 
     As described above, the CGW  13  performs the group management process on the rewrite target ECUs  19  to which an activation request is made, and thus gives an instruction for an activation request thereto in the unit of the group. A plurality of ECUs having a cooperative control relationship can be simultaneously upgraded. That is, it is possible to prevent the occurrence of a problem in a cooperative control process due to mismatching among versions of application programs of the plurality of rewrite target ECUs  19  having a cooperative control relationship. The CGW  13  performs installation in a predetermined order in the unit of the group. That is, the CGW  13  performs control such that processes from installation to activation are performed in the group unit. 
     The present embodiment relates to a configuration in which, after installation in the rewrite target ECU  19  belonging to the first group has been completed, activation in the rewrite target ECU  19  belonging to the first group is performed, and, subsequently, after installation in the rewrite target ECU  19  belonging to the second group has been completed, activation in the rewrite target ECU  19  belonging to the second group is performed. However, activation in the rewrite target ECU  19  belonging to the first group and activation in the rewrite target ECU  19  belonging to the second group may be performed successively. That is, installation in the rewrite target ECU  19  belonging to the first group may be completed, installation in the rewrite target ECU  19  belonging to the second group may be completed, and then activation in rewrite target ECU  19  belonging to the first group may be performed, and activation in the rewrite target ECU  19  belonging to the second group may be performed. In this case, activation in the rewrite target ECUs  19  belonging to the first group and the second group may be performed simultaneously. 
     In a case where the rewrite target ECU  19  includes a single-bank memory ECU, an instruction for installation in the single-bank memory ECU may be given last in a group. In a case where an instruction for installation is given to the rewrite target ECUs  19  having a cooperative operation relationship, the instruction for installation may be first given to the rewrite target ECU  19  that operates as a data transmission side, and the instruction for installation may be later given to the rewrite target ECU that operates as a data reception side. 
     The CGW  13  refers to the memory type in rewrite specification data and determines the installation order according to the memory type of the rewrite target ECU  19 . For example, installation is performed in an order of a double-bank memory, a single-bank suspend memory, and a single-bank memory. The CGW  13  stores in advance which of a data transmission side and a data reception side the ECU is as information regarding the ECUs  19  having a cooperative operation relationship, and determines an installation order of the rewrite target ECUs  19  on the basis of the information. 
     In a case where there are a plurality of groups, an installation order may be determined on the basis of, for example, the degree of urgency, the degree of safety, a function, or a time. The degree of urgency is an index indicating whether or not it is necessary to perform immediate installation. The degree of urgency is high in a case where there is a high probability that man-made disasters or accidents may occur if the ECU is left without installation. The degree of urgency is low in a case where there is a low probability that man-made disasters or accidents may occur even if the ECU is left without installation. Installation is preferentially performed on a group having a high degree of urgency. The degree of safety is an index of the restriction due to the type of microcomputer at the time of installation, and installation is performed in an ascending order of restriction, that is, in an order of a double-bank memory, a single-bank suspend memory, and a single-bank memory. The function is an index of user&#39;s convenience, and installation is preferentially performed on a group that is more convenient to a user. The time is an index of the time required for installation, and installation is preferentially performed on a group requiring a short installation time. 
     In a case where the CGW  13  instructs the first rewrite target ECU  19  and the second rewrite target ECU  19  belonging to the same group to perform installation, when the first rewrite target ECU  19  succeeds in installation, and the second rewrite target ECU  19  fails in installation, the CGW  13  instructs the second rewrite target ECU  19  to perform rollback and instructs the first rewrite target ECU  19  to perform rollback. 
     In a case where the CGW  13  instructs the rewrite target ECU  19  belonging to the first group and the rewrite target ECU  19  belonging to the second group to perform installation, when the rewrite target ECU  19  belonging to the first group fails in installation, the CGW  13  instructs the rewrite target ECU  19  belonging to the second group to perform installation. For example, in  FIG. 116 , in a case where rewriting is performed in the second group (S 1405 : YES) in a state in which the rewrite target ECU  19  belonging to the first group fails in installation, the CGW  13  skips the activation request instruction process (S 1408 ) for the first group and proceeds to step S 1407 . The CGW  13  returns to step S 1403  and initiates to perform installation on the second group, and performs the activation request instruction process on the second group in a case where the installation has been completed (S 1408 ). That is, even though the first group fails in update, the CGW  13  performs update on the second group. 
     In a case where there are two groups in a single campaign (within a single distribution package), the user&#39;s approval operation for the campaign and the user&#39;s approval operation for download are performed once, and the user&#39;s approval operation for installation and the user&#39;s approval operation for activation are performed twice for each group. That is, in a case where a function changed due to update differs for each group, it is desirable to perform the user&#39;s approval operation for installation and the user&#39;s approval operation for activation for each function. Since some users feel complicated about the user&#39;s approval operation for installation and the user&#39;s approval operation for activation for each group, the user&#39;s approval operation for installation and the user&#39;s approval operation for activation may be performed once for all groups. 
     Although the configuration in which a group to which the rewrite target ECU  19  belongs is determined by using the rewrite specification data has been exemplified, there may be a configuration in which a group to which the rewrite target ECU  19  belongs is stored in the CGW  13 . 
     (15) Rollback Execution Control Process 
     The rollback execution control process will be described with reference to  FIGS. 119 to 130 . The vehicle program rewriting system  1  executes the rollback execution control process in the CGW  13 . The rollback indicates writing for returning the memory of the rewrite target ECU  19  to a predetermined state, such as returning an application program to an original version, in a case where rewriting of the application program is stopped, and is to return a state of the rewrite target ECU  19  to a state before writing of write data is initiated from the viewpoint of the user. 
     As illustrated in  FIG. 119 , the CGW  13  includes a cancellation request determination unit  86   a , a rollback method specifying unit  86   b , and a rollback execution unit  86   c  in the rollback execution control unit  86 . The cancellation request determination unit  86   a  determines whether or not a rewrite cancellation request is generated during rewriting of an application program. For example, when the user operates the mobile terminal  6  and selects cancellation of program rewriting, the center device  3  that acquires information regarding the cancellation notifies the CGW  13  of a program rewrite cancellation request via the DCM  12 . 
     In a case where an abnormality occurs in the system, when the center device  3  is notified of the abnormality in the system, the center device  3  notifies the CGW  13  of the program rewrite cancellation request via the DCM  12 . The abnormality in the system is, for example, a case where a certain rewrite target ECU  19  succeeds in writing, but another rewrite target ECU  19  performing cooperative control with the certain rewrite target ECU  19  fails in writing. As mentioned above, when at least one of a plurality of rewrite target ECUs  19  performing cooperative control fails in writing, it is determined that the system is abnormal, and the center device  3  notifies the CGW  13  of the program rewrite cancellation request via the DCM  12  with respect to the rewrite target ECU  19  that has succeeds in writing. That is, causes of generation of the cancellation request include an operation performed by the user and the occurrence of an abnormality in the system. 
     The rollback method specifying unit  86   b  specifies a rollback method for returning a state of the rewrite target ECU  19  to a state before writing of write data is initiated according to the memory type of the flash memory mounted on the rewrite target ECU  19  and the data type of write data of a new program or an old program. That is, the rollback method specifying unit  86   b  specifies whether the flash memory is a single-bank memory, a single-bank suspend memory, or a double-bank memory as the memory type of the rewrite target ECU  19 , and specifies whether the write data is the entire data or difference data as the data type of the write data. 
     The rollback method specifying unit  86   b  specifies a first rollback process, a second rollback process, or a third rollback process according to the memory type and the data type. When the rollback method is specified by the rollback method specifying unit  86   b , the rollback execution unit  86   c  instructs the rewrite target ECU  19  to perform rollback in accordance with the rollback method, and operates the rewrite target ECU  19  with the old program. That is, the rollback execution unit  86   c  performs rollback for returning an operation state of the rewrite target ECU  19  to a state before rewriting of the application program is initiated. 
     Next, an operation of the rollback execution control unit  86  in the CGW  13  will be described with reference to  FIGS. 120 to 130 . The CGW  13  executes a rollback execution control program and thus performs the rollback execution control process. The CGW  13  performs a rollback method specifying process and a cancellation request determination process as the rollback execution control process. Each process will be described below. 
     (15-1) Rollback Method Specifying Process 
     When the rollback method specifying process is initiated, the CGW  13  analyzes the CGW rewrite specification data acquired from the DCM  12  (S 1501 ), specifies a rollback method on the basis of an analysis result thereof (S 1502 ), and finishes the rollback method specifying process. The CGW  13  acquires the memory type and the data type of a rollback program from the rewrite specification data illustrated in  FIG. 8 , and specifies a rollback method. The rollback method may be specified by using the data type of the new program when the data type is the same as that of the old program (rollback program). 
     That is, in a case where the flash memory of the rewrite target ECU  19  is a single-bank memory and the write data is the entire data, as a rollback method when a cancellation request is generated, the CGW  13  immediately stops distribution of the entire data, and specifies a method (first rollback process) in which data of the old application program is written into a rewrite area in the rewrite target ECU  19  to be rewritten into the old application program. The old application program (rollback rewrite data) for a single-bank memory is included in a distribution package along with an update program, and the CGW  13  distributes the old application program to the rewrite target ECU  19  in the same manner as in the new application program. 
     When the flash memory of the rewrite target ECU  19  is a single-bank memory and write data is difference data, as a rollback method when a cancellation request is generated, the CGW  13  continues distribution of the difference data, and specifies a method (second rollback process) in which the difference data is written into a rewrite area in the rewrite target ECU  19  to be rewritten into the new application program, then the difference data of the old application program is distributed, and the old data is written into the rewrite area in the rewrite target ECU  19  to be rewritten into the old application program. 
     In a case where write data is difference data, the rewrite target ECU  19  restores the new application program by using the current application program written in the flash memory and the difference data acquired from the CGW  13 , and writes the new application program. In a state in which a different application program is written in the flash memory, the write target ECU  19  cannot restore the new application program by using the difference data. Thus, in a single-bank memory, it is necessary to perform a process of rewriting data into the new application program. Here, for example, when a version of the current application program is 1.0 and a version of the new application program is 2.0, a rewrite program (rewrite data) is difference data for updating the version 1.0 to the version 2.0, and rollback rewrite data is difference data for updating the version 2.0 to the version 1.0. 
     When the flash memory of the rewrite target ECU  19  is a single-bank suspend memory or a double-bank memory, the CGW  13  continues distribution of write data, and specifies a method (third rollback process) in which, when an active bank is the bank-A and an inactive bank is the bank-B in the rewrite target ECU  19 , the write data is written into the bank-B that is the inactive bank such that the new application program is installed, but switching of the active bank from bank-A to bank-B is suppressed. 
     (15-2) Cancellation Request Determination Process 
     When it is specified that rewriting of an application program is initiated in the rewrite target ECU  19 , the CGW  13  initiates the cancellation request determination process, determines whether or not the rewriting of the application program has been completed (S 1511 ), and determines whether or not a cancellation request has been generated (S 1512 ). That is, as described above, the CGW  13  determines whether or not the cancellation request has been generated due to an operation performed by the user, the occurrence of abnormality in the system, or the like. 
     When it determines that the cancellation request is generated before the rewriting of the application program has been completed, that is, the cancellation request is generated during installation (S 1512 : YES), the CGW  13  specifies the rewrite target ECU  19  that is a rollback target (S 1513 ). It is assumed that the rewrite target ECUs  19  belonging to the same group are the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ), the ECU (ID 1 ) is a single-bank memory, the ECU (ID 2 ) and the ECU (ID 3 ) are double-bank memories, installation in the ECU (ID 1 ) has been completed, and a cancellation request is generated during installation in the ECU (ID 2 ). In this case, the CGW  13  determines whether or not rollback is required for all of the rewrite target ECUs  19  belonging to the first group in S 1413 . 
     The CGW  13  specifies the ECU (ID 1 ) in which the entire application program is rewritten and the ECU (ID 2 ) in which a part of the application program is rewritten as rollback targets. The CGW  13  determines the memory type of the flash memories of the rewrite target ECUs  19  that are the specified rollback targets, and determines whether each flash memory is a single-bank memory, a single-bank suspend memory, or a double-bank memory (S 1514  and S 1515 ). When it is determined that the flash memory is a single-bank memory (S 1514 : YES), the CGW  13  determines the data type of the rollback program, and determines whether the rollback write data is the entire data or difference data (S 1516  and S 1517 ). 
     When it is determined that the rollback write data is the entire data (S 1516 : YES), the CGW  13  proceeds to the first rollback process (S 1518 ; corresponding to a rollback execution procedure). When the first rollback process is initiated, the CGW  13  immediately stops distribution of the write data that is the new program (S 1531 ). The CGW  13  acquires the rollback write data (old program) that is the entire data from the DCM  12  and distributes the rollback write data to the rewrite target ECU  19 . The rewrite target ECU  19  writes the data of the old application program acquired from the CGW  13  into the flash memory such that the data is rewritten into the old application program (S 1532 ), finishes the first rollback process, and returns to the cancellation request determination process. 
     When it is determined that the rollback write data is difference data (S 1517 : YES), the CGW  13  proceeds to the second rollback process (S 1519 ; corresponding to a rollback execution procedure). When the second rollback process is initiated, the CGW  13  continues distribution of write data that is a new program (S 1541 ), restores the difference data in the rewrite target ECU  19 , and writes the difference data into the flash memory such that the difference data is rewritten into the new application program (S 1542 ). The CGW  13  distributes the write data of the old application program acquired from the DCM  12  to the rewrite target ECU  19  after rewriting into the new application program has been completed (S 1543 ). The difference data that is the write data of the old application program is restored in the rewrite target ECU  19 , and is written into the flash memory to be rewritten into the old application program (S 1544 ), and the CGW  13  finishes the second rollback process and returns to the cancellation request determination process. 
     When it is determined that the rewrite target ECU  19  is a single-bank suspend memory ECU or a double-bank memory ECU (S 1515 : YES), the CGW  13  proceeds to the third rollback process (S 1520 ; corresponding to a rollback execution procedure). In this case, the CGW  13  proceeds to the third rollback process regardless of the rewrite data type. When the third rollback process is initiated, the CGW  13  continues distribution of write data (S 1551 ), writes the write data into an inactive bank (bank-B) in the rewrite target ECU  19  such that the write data is rewritten into the new application program (S 1552 ). The CGW  13  suppresses switching of an active bank from the old bank (active bank: bank-A) to the new bank (inactive bank: bank-B) (S 1553 ), finishes the third rollback process, and returns to the cancellation request determination process. In addition to suppressing the switching of the active bank, the CGW  13  may roll back the inactive bank in which the version 2.0 is written to a state (for example, the version 1.0) before rewriting into the new application program, as illustrated in  FIG. 126 . 
     When the CGW  13  returns to the cancellation request determination process, the CGW  13  determines whether or not the rollback process has been performed on all the rewrite target ECUs  19  that are the rollback targets (S 1521 ). For example, in the exemplified case where the rewrite target ECUs  19  are the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ), first, the CGW  13  performs the first rollback process or the second rollback process on the single-bank memory ECU (ID 1 ) in which installation was being performed, according to the rollback data type. Thereafter, the CGW  13  performs the third rollback process on the double-bank memory ECU (ID 2 ) in which installation has been completed. 
     The CGW  13  performs the first rollback process or the second rollback process on the single-bank memory ECU (ID 1 ) according to the rewrite data type. When it is determined that the rollback process has not been performed on all the rewrite target ECUs  19  that are the rollback targets (S 1521 : NO), the CGW  13  returns to step S 1513  and repeatedly performs step S 1513  and the subsequent steps. When it is determined that the rollback process has been performed on all the rewrite target ECUs  19  that are rollback targets (S 1521 : YES), the CGW  13  finishes the cancellation request determination process. The CGW  13  simultaneously instructs the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ) belonging to the first group on which the rollback process has been performed, to activate the old application programs. The ECU (ID 1 ) having a single-bank memory switches to the old application program through restart. The ECU (ID 2 ) and the ECU (ID 3 ) having double-bank memories are started in the same active bank (bank-A) as before instead of the inactive bank (bank-B) in which the update program is written. When the user&#39;s intention changes and the program update is executed again, the new application program is written in the ECU (ID 1 ) and the ECU (ID 3 ). However, since the new application program has already been installed in the inactive bank of the ECU (ID 2 ), writing is omitted. 
     When it is determined that rewriting of the application program has been completed without the cancellation request being generated (S 1511 : YES), the CGW  13  determines whether activation has been completed (S 1522 ), and determines whether the cancellation request has been generated (S 1523 ). 
     When it is determined that the cancellation request has been generated before completion of the activation, that is, the cancellation request has been generated during the activation (S 1523 : YES), the CGW  13  determines whether or not an activation instruction has reached the rewrite target ECU  19 , and determines whether or not switching of the active bank has been completed (S 1524 ). 
     When it is determined that the activation instruction has not reached the rewrite target ECU  19  and that the switching of the active bank is not completed (S 1524 : NO), the CGW  13  performs a fourth rollback process (S 1525 ). It is assumed that the CGW  13  does not switch the active bank as the fourth rollback process. Alternatively, the CGW  13  may return the inactive bank to a state before rewriting into the new application program without switching the active bank. When the active bank is not switched, the CGW  13  uses a bank in which the version 1.0 is written as the active bank, and uses a bank in which the version 2.0 is written as the inactive bank, as illustrated in  FIG. 127 . When the inactive bank is returned to the state before rewriting into the new application program without switching the active bank, the CGW  13  uses the bank in which the version 1.0 is written as the active bank, and rolls back the inactive bank that is a bank in which the version 2.0 is written, to a state (version 1.0) before rewriting into the new application program, as illustrated in  FIG. 128 . 
     When it is determined that the activation instruction has reached the rewrite target ECU  19  and switching of the active bank has been completed (S 1524 : YES), the CGW  13  performs a fifth rollback process. The completion of switching of the active bank indicates a state in which a bank in which the version 2.0 is written switches from the inactive bank to the active bank, and a bank of the version 1.0 switches from the active bank to the inactive bank, as illustrated in  FIG. 129 . As the fifth rollback process, the CGW  13  switches the active bank, or switches the active bank after returning the inactive bank to the state before rewriting into the new application program. In a case where switching the active bank, the CGW  13  switches the bank in which the version 2.0 is written from the active bank to the inactive bank, and switches the bank in which the version 1.0 is written from the inactive bank to the active bank, as illustrated in  FIG. 129 . In a case of switching the active bank after returning the inactive bank to the state before rewriting into the new application program, as illustrated in  FIG. 130 , the CGW  13  rolls back the active bank that is the bank in which the version 2.0 is written, to the state (for example, the version 1.0) before rewriting into the new application program, switches the bank that is returned to the state before rewriting into the new application program from the active bank to the inactive bank, and switches the bank in which the version 1.0 is written from the inactive bank to the active bank. 
     As described above, the CGW  13  performs the rollback execution control process, and, thus, when a rewrite cancellation request is generated during rewriting of an application program, the CGW  13  returns an operation state of the rewrite target ECU  19  to a state before rewriting of the application program is initiated from the viewpoint of the user. Thus, all the rewrite target ECUs  19  belonging to the same group can be returned to original program versions together. Even in a case where difference data is used in the next program update, write data can be correctly restored. 
     (16) Rewrite Progress Situation Display Control Process 
     The rewrite progress situation display control process will be described with reference to  FIGS. 131 to 143 . The vehicle program rewriting system  1  performs the rewrite progress situation display control process in the CGW  13 . In order to inform the user of an application program rewrite progress situation, the mobile terminal  6  and the in-vehicle display  7  as the display terminal  5  display a progress situation. The progress situation to be displayed includes not only a case where a program is updated but also a case where the program is rolled back due to, for example, a cancellation operation performed by the user or an update failure. 
     As illustrated in  FIG. 131 , the CGW  13  includes a cancellation detection unit  87   a , a write instruction unit  87   b , and a notification instruction unit  87   c  in the rewrite progress situation display control unit  87 . The cancellation detection unit  87   a  detects cancellation regarding rewriting of a program for rewriting first write data stored in the rewrite target ECU  19  with second write data acquired from the center device  3 . The cancellation detection unit  87   a  detects a cancellation operation performed by the user or an error such as a failure in writing into the rewrite target ECU  19 . The cancellation detection unit  87   a  performs a rollback process even in a case where a predetermined abnormality is detected, such as a case where write data is incompatible with the rewrite target ECU  19 , a case where falsification of the write data is detected, or a case where an error of writing into the rewrite target ECU  19  occurs, and thus detection of these abnormalities is also treated as detection of cancellation. 
     The write instruction unit  87   b  distributes the second write data to the rewrite target ECU  19  and instructs the rewrite target ECU  19  to write the second write data. The notification instruction unit  87   c  gives an instruction for a notification of a progress situation related to rewriting of an application program. The notification instruction unit  87   c  gives an instruction for a notification of the progress situation related to rewriting of the application program in a first aspect while the second write data is being distributed by the write instruction unit  87   b , and gives an instruction for a notification of the progress situation related to the rewriting of the application program in a second aspect when the cancellation detection unit  87   a  detects cancellation. When cancellation is detected by the cancellation detection unit  87   a  while the second write data is being distributed, the write instruction unit  87   b  continues distribution of the second write data. 
     The CGW  13  specifies rewriting of the application programs in the rewrite target ECU  19  by specifying an internal state of the rewrite target ECU  19 , specifying an instruction from the center device  3 , or specifying the user operation. When the rewriting of the application program is specified, the CGW  13  determines whether the rewriting is rewriting (installation) during the normal time or rewriting (uninstallation) during rollback. When it is determined whether the rewriting is rewriting during the normal time or rewriting is performed during rollback by specifying the internal state of the rewrite target ECU  19 , specifying the instruction from the center device  3 , and specifying the user operation, the CGW  13  calculates a progress situation of rewriting during the normal time or during rollback on the basis of the determination result, and instructs the display terminal  5  to display the calculated progress situation. 
     The CGW  13  instructs the display terminal  5  to display the progress situation during the normal time or the progress situation during rollback in accordance with the rewrite determination result indicating whether the rewriting is rewriting during the normal time or rewriting during rollback. The CGW  13  gives an instruction such that progress display indicating the progress situation of the rewriting during the normal time is displayed to be differentiated from progress display indicating the progress situation of the rewriting during rollback. That is, the CGW  13  displays the progress situation in the first aspect in a case of the rewriting during the normal time, and displays the progress situation in the second aspect different from the first aspect in a case of the rewriting during rollback. The CGW  13  differentiates the progress display during the normal time from the progress display during rollback by differentiating characters, items, colors, numerical values, flashing, and the like on a display screen between the normal time and the rollback time, as an aspect related to display when a progress situation is displayed. The CGW  13  differentiates progress display during the normal time from progress display during rollback by differentiating sounds, vibrations, and the like between the normal time and the rollback time, as an aspect other than the display at the time of displaying the progress display. 
     Next, an operation of the CGW  13  will be described with reference to  FIGS. 132 to 143 . The CGW  13  executes a rewrite progress situation display control program and thus performs the rewrite progress situation display control process. 
     When a rewrite initiation signal indicating that rewriting of a program has been initiated in the rewrite target ECU  19  is received (when installation of the program is initiated in the rewrite target ECU  19 ), the CGW  13  initiates the rewrite progress situation display control process. When rewrite progress situation display control process is initiated, the CGW  13  analyzes the CGW rewrite specification data, specifies the memory type and the write data type of the flash memory of the rewrite target ECU  19 , and specifies the rewrite target ECU  19  during the normal time (S 1601 ). When the memory type and the write data type of the flash memory of the rewrite target ECU  19 , and a size of an update program are specified (S 1602 ), the CGW  13  calculates a rewrite progress situation during the normal time according to the specified result, and gives an instruction for display of the rewrite progress situation during the normal time (S 1603 ). The display terminal  5  displays rewrite progress situation in a rewrite display aspect during the normal time in response to the instruction from the CGW  13 . 
     The CGW  13  determines whether or not rewriting of the application program has been completed (S 1604 ), and determines whether or not a cancellation request has been generated (S 1605 ; corresponding to a cancellation detection procedure). The CGW  13  repeatedly performs S 1604  and S 1605 , and updates and displays a progress situation at any time, for example, during installation in the rewrite target ECU (ID 1 ). 
     When a rewrite completion signal indicating that the rewriting of the application program has been completed in the rewrite target ECU  19  is received, and it is determined that the rewriting of the application program has been completed without a cancellation request being generated (S 1604 : YES), the CGW  13  finishes the display of the rewrite progress situation during the normal state (S 1606 ), and determines whether or not rewriting has been completed in all the rewrite target ECUs  19  (S 1607 ). For example, when installation has been completed in the rewrite target ECU (ID 1 ), the CGW  13  displays the progress situation of the ECU (ID 1 ) as 100%. When it is determined that rewriting is not completed yet in all the rewrite target ECUs  19  (S 1607 : NO), the CGW  13  returns to step S 1601  and repeatedly performs step S 1601  and the subsequent steps. The CGW  13  performs progress display related to the rewrite target ECU (ID 2 ) subjected to next installation, for example, after S 1601 . 
     When it is determined that the cancellation request has been generated before completion of rewriting of the application program (S 1605 : YES), the CGW  13  finishes the display of the rewrite progress situation during the normal time (S 1608 ), and proceeds to a display control process during rollback (S 1609 ; corresponding to a notification instruction procedure). Here, the cancellation request includes a cancellation request made by the user, and a cancellation request made by the system based on a failure in writing into the rewrite target ECU  19  or the like. 
     When the display control process during rollback is initiated, the CGW  13  specifies the rewrite target ECU  19  during rollback (S 1611 ), and specifies the memory type of the flash memory of the rewrite target ECU  19  during rollback, and the data type and a size of a rollback program (S 1612 ). The CGW  13  performs a process, for example, assuming that the rewrite target ECUs  19  belonging to the same group are the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ), installation has been completed in the ECU (ID 1 ) and the ECU (ID 2 ), and a cancellation request has been generated during installation in the ECU (ID 3 ). In this case, the CGW  13  specifies whether or not rollback is required and a rollback method according to the memory type and the write data type of each rewrite target ECU  19 . 
     The CGW  13  specifies the memory type and the write data type of the flash memory of the rewrite target ECU  19  that is a rollback target, and specifies whether or not rollback is required and a rollback method (the first rollback process in S 1518 , the second rollback process in S 1519 , and the third rollback process in S 1520 ). The CGW  13  calculates a progress situation according to the specified result, displays the progress situation, and gives an instruction for display of a rewrite progress situation during rollback (S 1613 ). An amount of write data in the CGW  13  differs depending on the first to third rollback processes. Thus, the CGW  13  determines a total amount of write data according to the first to third rollback processes, and calculates the progress (how much of the data has been written) on the basis of a ratio of an amount of written data. The CGW  13  determines whether or not rewriting as the rollback process of the application program has been completed (S 1614 ). 
     The CGW  13  distributes the write data to the rewrite target ECU  19  until the rewriting as the rollback process has been completed, and repeatedly performs the above-described progress calculation and display instruction. In S 1613 , the CGW  13  displays the calculated progress situation in a display aspect during rollback. In S 1614 , the CGW  13  determines whether or not the rollback for the ECU (ID 3 ) in which rewriting was being performed is normally completed. 
     When it is determined that the rollback for the rewrite target ECU  19  that is a rollback target has been completed (S 1614 : YES), the CGW  13  finishes displaying the rewrite progress situation during rollback (S 1615 ). For example, the CGW  13  continues to display that rollback has been completed by 100% for the ECU (ID 3 ). 
     The CGW  13  determines whether or not rewriting during rollback has been completed in all rollback target ECUs  19  (S 1616 ). When it is determined that rewriting during rollback is not completed for all the rollback target ECUs  19  (S 1616 : NO), the CGW  13  returns to step S 1611  and repeatedly performs step S 1611  and the subsequent steps. 
     For example, in a case where the ECU (ID 1 ) in which installation has been completed is a single-bank memory, the CGW  13  displays the rewrite progress situation during rollback (S 1613 ). On the other hand, for example, in a case where the ECU (ID 2 ) in which installation has been completed is a double-bank memory and does not require rollback, the ECU (ID 2 ) is excluded from a rewrite target during rollback. When the rollback for the ECU (ID 3 ) and the ECU (ID 1 ) has been completed, rewriting in the rewrite target ECUs  19  that are all rollback targets has been completed (S 1616 : YES), and the CGW  13  finishes the display control process during rollback. 
     In the above description, the CGW  13  performs the display control process during rollback, but the in-vehicle display ECU  7  or the center device  3  may be configured to perform the display control process during rollback while acquiring necessary information from the CGW  13 . There may be a configuration in which the CGW  13  performs rewriting during rollback, progress calculation, and the like, and the in-vehicle display ECU  7  or the center device  3  performs display control during rollback. That is, there is no limitation to the configuration in which only the CGW  13  has the function of the display control device, and the function of the display control device may be distributed between the CGW  13  and the in-vehicle display ECU  7 , or the function of the display control device may be distributed between the CGW  13  and the center device  3 . 
     Hereinafter, display of a rewrite progress situation will be described with reference to  FIGS. 134 to 142 . As illustrated in  FIG. 134 , the display terminal  5  displays the overall progress situation as “normal rewriting” in display of the rewrite progress situation during the normal time, and thus allows the user to recognize that the display is display of the rewrite progress situation during the normal time. The “normal rewriting” may be displayed as “installation”. As a first aspect, the display terminal  5  displays the rewrite progress situation during the normal time. 
     The display terminal  5  displays the progress state as “waiting for synchronization instruction” for the rewrite target ECU  19  that completes rewriting of an application program and is waiting for a synchronization instruction for activating the update program, and displays the progress state as “normal rewriting” for the rewrite target ECU  19  that is rewriting an application program. The “waiting for synchronization instruction” may be displayed as “waiting for activation”. The “normal rewriting in progress” may be displayed as “installation in progress”.  FIG. 134  exemplifies a case where the ECU (ID 0001 ) and the ECU (ID 0002 ) have completed rewriting of application programs and are waiting for a synchronization instruction, and the ECU (ID 0003 ) is in a normal-rewriting-in-progress state. 
     When a cancellation request is generated in this state, for example, as illustrated in  FIG. 135 , the display terminal  5  displays a pop-up message “cancellation has been received; the state before rewriting is restored; and please wait for a while”, and thus allows the user to recognize that the cancellation has been received. As a second aspect, the display terminal  5  performs display indicating that cancellation has been received. 
     When the CGW  13  prepares for rewriting during rollback, the display terminal  5  displays the entire progress situation as “rollback rewrite” as illustrated in  FIG. 136 , and allows the user to recognize that the display is a display of the rewrite progress situation during rollback. The “rollback rewrite” may be displayed as “uninstallation”. The display terminal  5  displays the progress situation of all the rewrite target ECUs  19  as “waiting for rollback”, and displays a numerical value of a progress graph indicating the rewrite progress situation as “0%”. The “waiting for rollback” may be displayed as “waiting for uninstallation”. Here, the ECU (ID 0001 ) and the ECU (ID 0002 ) are examples of single-bank memory ECUs and the ECU (ID 0003 ) is an example of a double-bank memory ECU, and rollback is required for the ECU (ID 0001 ) and the ECU (ID 0002 ) in which installation has been completed in addition to the ECU (ID 0003 ) in which rewriting was being performed.  FIG. 136  illustrates an aspect in which one overall progress situation is displayed, and the progress situation of each rewrite target ECU  19  is displayed. 
     When rewrite during rollback is initiated, the CGW  13  displays the progress state of the rewrite target ECU  19  in a rewriting state as “rollback rewrite in progress (or uninstallation in progress)” as illustrated in  FIG. 137 . As a third aspect, the display terminal  5  displays the rewrite progress situation during rollback.  FIG. 137  exemplifies a case where the ECU (ID 0003 ) is in a rollback-rewrite-in-progress state. When the rollback for the rewrite target ECU  19  has been completed, the display terminal  5  displays the progress state as “rollback completed” and displays the progress situation as 100% for the rewrite target ECU  19  that has completed the rewrite as illustrated in  FIG. 138 . 
     In a case where the rollback target ECU  19  is a single-bank memory ECU and the entire data is to be rewritten, the display terminal  5  causes the display of the progress graph to transition as illustrated in  FIG. 139 . That is, in a case where the rollback target ECU  19  is a single-bank memory ECU and the entire data is to be rewritten, distribution of the entire data is immediately stopped, and data of the old application program is written into the flash memory in the rewrite target ECU  19  to be rewritten into the old application program (first rollback process). 
     For example, when a cancellation request is generated in a stage in which normal rewriting has been completed up to “50%” ( FIG. 139( a ) ), the display terminal  5  displays the numerical value of the progress graph as “0%” ( FIG. 139( b ) ), increases a numerical value of the progress graph in accordance with the progress of writing the data of the old application program, and rewrites the data into the old application program ( FIGS. 139( c ), 139( d ), and 139( e ) ). When the rewriting into the old application program has been completed by 100%, the display terminal  5  displays that the rewrite target ECU  19  “has completed rollback”.  FIG. 139  and  FIGS. 140 to 142  described later illustrate progress display of the individual ECUs. 
     When the rollback target ECU  19  is a single-bank memory ECU and difference data is to be rewritten, the display terminal  5  causes the display of the progress graph to transition as illustrated in  FIG. 140 or 141 . That is, when the rollback target ECU  19  is a single-bank memory and the difference data is to be rewritten, the CGW  13  continues to distribute the difference data, writes the difference data into the flash memory in the rewrite target ECU  19  and thus rewrites the difference data into the new application program. The CGW  13  distributes the data of the old application program to the rewrite target ECU  19 , writes the old data into the flash memory in the rewrite target ECU  19 , and thus rewrites the old data into the old application program (second rollback process). 
     For example, when a cancellation request is generated in a stage in which normal rewriting (installation) has been completed up to “50%” ( FIG. 140( a )  and FIG.  141 ( a )), the display terminal  5  displays a numerical value of the progress graph as “0%” ( FIG. 140( b )  and  FIG. 141( b ) ). The rewrite target ECU  19  validates the difference data that has been written so far, and continues to write the difference data that is distributed from the CGW  13 . That is, the progress display indicating that installation has been completed switches from display of “0%” to a ratio corresponding to the validated “50%” ( FIG. 140( c )  and  FIG. 141( c ) ). The display terminal  5  increases the numerical value of the progress graph in accordance with the progress in which the rewrite target ECU  19  writes the difference data of the new program distributed from the CGW  13  ( FIGS. 140( d ), 140( e ), 141( d ), and 141( e ) ). After the rewrite target ECU  19  completes rewriting of the new application program, the display terminal  5  subsequently increases the numerical value of the progress graph in accordance with the progress in which the rewrite target ECU  19  writes the difference data of the old application program distributed from the CGW  13  ( FIGS. 140( f ), 140( g ), 141( f ), and 141( g ) ). That is, the display terminal  5  displays the progress situation of writing of the new program and the progress situation of writing of the old program in accordance with the occurrence of continuous installation of the new program and installation of the old program as the rollback process. 
     In this case, as illustrated in  FIG. 140 , the display terminal  5  may display a rewrite portion of the new application program as “100%” in the progress graph on the left and display a rewrite portion of the old application program as “100%” in the progress graph on the right, so that the entire width of the progress graph may be “200%”. In this case, the display terminal  5  calculates a progress percentage of the new application program on the basis of a file size of the new application program and a cumulative data size of the written new application program, calculates a progress percentage of the old application program on the basis of a file size of the old application program and a cumulative data size of the written old application program, and thus displays the progress situation. 
     Further, as illustrated in  FIG. 141 , the display terminal  5  may set the entire width of the progress graph to “100%” by setting a rewrite portion of the new application program to “50%” and setting a rewrite portion of the old application program to “50%”. In this case, the display terminal  5  calculates and displays a progress percentage on the basis of a sum value of the file size of the written new application program and the file size of the old application program and a sum value of the cumulative data size of the new application program and the cumulative data size of the old application program. 
     In a case where the rollback target ECU  19  is subjected to rewriting into a single-bank suspend memory ECU or a double-bank memory ECU, as illustrated in  FIG. 142 , the display terminal  5  causes the display of the progress graph to transition. That is, in a case of rewriting when the rollback target ECU  19  is a single-bank suspend memory ECU or a double-bank memory ECU, the CGW  13  continues to distribute write data to the rewrite target ECU  19 , writes the write data into the inactive bank in the rewrite target ECU  19 , and rewrites the write data into the new application program (third rollback process). 
     For example, when a cancellation request is generated in a stage in which normal rewriting (installation) has been completed up to “50%” ( FIG. 142( a ) ), the display terminal  5  displays the numerical value of the progress graph as “0%” ( FIG. 142( b ) ). The rewrite target ECU  19  validates the difference data that has been written so far, and continues to write the difference data that is distributed from the CGW  13 . That is, the progress display indicating that installation has been completed switches from display of “0%” to a ratio corresponding to the validated “50%” ( FIG. 142( c ) ). The display terminal  5  increases the numerical value of the progress graph in accordance with the progress in which the rewrite target ECU  19  writes the write data distributed from the CGW  13  ( FIGS. 142( d ) and 142( e ) ). In the present embodiment, a description has been made of a case where the CGW  13  performs the rewrite progress situation display control process, but the display terminal  5  may perform the rewrite progress situation display control process. 
     As described above, since the rewrite progress situation display control process is performed, the display terminal  5  displays a progress situation in a display aspect of differentiating rewriting of an application program between rewriting (installation) during the normal time and rewriting (uninstallation) during rollback on the basis of the rollback process. The user can recognize that rollback is in progress by receiving cancellation of an update program. Although the configuration of displaying a progress situation for each rewrite target ECU  19  has been described above, as illustrated in  FIG. 143 , a configuration of collectively displaying a progress situation for the rewrite target ECUs  19  may be used. In this case, the display terminal  5  displays a single progress state instead of individually displaying progress states for the three rewrite target ECUs  19 . The CGW  13  calculates the progress on the basis of a ratio of an amount of written data to a total amount of write data generated in the three rewrite target ECUs  19  as the rollback process. 
     (17) Difference Data Consistency Determination Process 
     The difference data consistency determination process will be described with reference to  FIGS. 144 to 147 . The vehicle program rewriting system  1  performs the difference data consistency determination process before installation is initiated in the rewrite target ECU  19 . 
     As illustrated in  FIG. 144 , the ECU  19  includes, in the difference data consistency determination unit  103 , a difference data acquisition unit  103   a , a consistency determination unit  103   b , a write data restoration unit  103   c , a data writing unit  103   d , a data verification value calculation unit  103   e , a rewrite specification data acquisition unit  103   f , a data identification information acquisition unit  103   g , and a rewrite bank information acquisition unit  103   h.    
     The difference data acquisition unit  103   a  acquires difference data that is used to rewrite a data storage area of an electronic control unit which is the rewrite target ECU  19  and that indicates a difference between old data and new data. The consistency determination unit  103   b  determines whether or not the difference data is consistent with a data storage area or stored data on the basis of first determination information related to the stored data that is stored in the data storage area of the flash memory and second determination information acquired in a manner linked to the difference data. For example, the first determination information is a data verification value for the stored data, and the second determination information is a data verification value for old data or a data verification value for new data. The write data restoration unit  103   c  restores write data by using the difference data and the stored data when it is determined by the consistency determination unit  103   b  that the consistency of the difference data is positive, and does not restore the write data when it is determined by the consistency determination unit  103   b  that the consistency of the difference data is negative. When the write data is restored by the write data restoration unit  103   c , the data writing unit  103   d  stores the restored write data into the data storage area. The data verification value calculation unit  103   e  calculates a data verification value for each of blocks obtained by dividing the stored data into one or more blocks. The data verification value calculation unit  103   e  acquires the data verification value for each block received along with the difference data. 
     The rewrite specification data acquisition unit  103   f  acquires rewrite specification data corresponding thereof in the CGW rewrite specification data from the CGW  13 . The data identification information acquisition unit  103   g  acquires data identification information stored in the difference data and data identification information of an old application program that is the old data. The data identification information is information for identifying whether or not the difference data is data for the ECU, and is, for example, data calculated by applying a predetermined algorithm to the old data. 
     The rewrite bank information acquisition unit  103   h  acquires rewrite bank information stored in the rewrite specification data acquired from the CGW  13  and rewrite bank information of the old application program that is old data. The rewrite bank information is information indicating which bank of the flash memory is to be written with the difference data that is the write data. In a case where the rewrite target ECU  19  is a double-bank memory or a single-bank suspend memory, the bank-A or the bank-B is designated. In a case where the rewrite target ECU  19  is a single-bank memory, the rewrite bank information is not used. When the difference data distributed from the CGW  13  is received by the write data receiving unit  101 , the consistency determination unit  103   b  determines the consistency of the difference data by using at least one of the data identification information, the data verification value, and the rewrite bank information. 
     Next, an operation of the difference data consistency determination unit  103  in the rewrite target ECU  19  will be described with reference to  FIGS. 145 to 147 . The rewrite target ECU  19  executes a difference data consistency determination program and thus performs the difference data consistency determination process. When the difference data consistency determination process is initiated, the rewrite target ECU  19  acquires data identification information, a data verification value, and rewrite bank information related to difference data as first determination information for determining the consistency of the difference data (S 1701 ). The rewrite target ECU  19  acquires data identification information, data verification value of old data, a data verification value of new data, and rewrite bank information as second determination information (S 1702 ). 
     The rewrite target ECU  19  determines whether or not the data identification information of the first determination information matches the data identification information of the second determination information, and whether or not the rewrite bank information of the first determination information matches the rewrite bank information of the second determination information (S 1703 ). When it is determined that the data identification information of the first determination information does not match the data identification information of the second determination information, or the rewrite bank information of the first determination information does not match the rewrite bank information of the second determination information (S 1703 : NO), the rewrite target ECU  19  determines that the write data is improper, notifies the CGW  13  of error information, and finishes the difference data consistency determination process. 
     When it is determined that the data identification information of the first determination information matches the data identification information of the second determination information and that the rewrite bank information of the first determination information matches the rewrite bank information of the second determination information (S 1703 : YES), the rewrite target ECU  19  collates the data verification value of the first determination information with the data verification value of the new data of the second determination information, and determines whether or not both of the data verification values match each other (S 1704 ; corresponding to a consistency determination procedure). When it is determined that both of the data verification values do not match each other (S 1704 : NO), the rewrite target ECU  19  collates the data verification value of the first determination information with the data verification value of the old data of the second determination information, and determines whether both of the data verification values match each other (S 1705 ; corresponding to a consistency determination procedure). 
     When it is determined that both of the data verification values match each other (S 1705 : YES), the rewrite target ECU  19  restores write data (S 1706 ; corresponding to a write data restoration procedure), writes the restored write data into the flash memory (S 1707 ; corresponding to a data write procedure), and determines whether or not writing of the entire write data has been completed (S 1708 ). When it is determined that writing of the entire write data has not been completed (S 1708 : NO), the rewrite target ECU  19  returns to step S 1703  and repeatedly performs step S 1703  and the subsequent steps. When it is determined that all writing of the entire write data has been completed (S 1708 : YES), the rewrite target ECU  19  finishes the difference data consistency determination process. 
     When it is determined that the data verification value of the first determination information does not match the data verification value of the new data of the second determination information (S 1704 : NO), and it is determined that the data verification value of the first determination information does not match the data verification value of the old data of the second determination information (S 1705 : NO), the rewrite target ECU  19  determines whether or not writing for a first block is performed (S 1709 ). 
     When it is determined that writing for the first block is performed (S 1709 : YES), the rewrite target ECU  19  determines whether or not writing of the entire write data has been completed because writing for the first block has not been completed (S 1708 ). When it is determined that writing for the first block is not performed, that is, writing for a second block and the subsequent blocks is performed (S 1709 : NO), the rewrite target ECU  19  retries the writing (S 1710 ), and determines whether or not writing of entire write data has been completed (S 1708 ). 
     A description will be made of a case where the rewrite target ECU  19  is a single-bank memory ECU with reference to  FIG. 146 . Data identification information (old) and a CRC value (data verification value) computed for each block of old data are attached to difference data distributed from the CGW  13 . The data identification information (old) is data calculated by applying a predetermined algorithm to the old data (old application program). When the data identification information is used as determination information, the rewrite target ECU  19  collates the data identification information (old) attached to the difference data with the data identification information (old) of the program (old data) stored in the flash memory, and determines the consistency of the difference data. The data identification information (old) stored in the flash memory is information stored together when the program is written into the flash memory of the rewrite target ECU  19 . Alternatively, a predetermined number of bits from a leading address of the program written in the flash memory may be regarded as data identification information (old). 
     When the data verification value is used as determination information, the rewrite target ECU  19  computes a CRC value for each block of the program stored in the flash memory, collates a CRC value (CRC (B 1  to Bn)) for the old data attached to the received difference data and a CRC value (CRC (B 1 ′ to Bn′)) for the new data with the computed CRC value, and determines the consistency of the difference data. When no new program is written in the flash memory, the received CRC value in all blocks matches the computed CRC value. In a case where writing is stopped in a state in which the new program is written up to m (&lt;n) blocks of the flash memory, and the writing is resumed, the computed CRC value matches the CRC value (CRC (B 1 ′ to Bn′) of the new data in the blocks  1  to m, and thus the rewrite target ECU  19  skips a write process (S 1706  and S 1707 ). The rewrite target ECU  19  performs the write process (S 1706  and S 1707 ) from the block m+1 by checking match with the CRC value (CRC (B 1  to Bn)) for the old data. 
     Data identification information (new) of a new program (new data) and a CRC value (CRC (B 1 ′ to Bn′)) for each block may be attached to the difference data. The rewrite target ECU  19  writes the difference data into the flash memory, stores the data identification information (new) together when the new program is installed, and uses the difference data to determine the consistency in the next program update. When installation of the new program is completed, the rewrite target ECU  19  reads the new program written in the flash memory for each block, computes a CRC value, compares the CRC value with the CRC value attached to the difference data, and verifies whether or not the new program has been correctly written. 
     A description will be made of a case where the rewrite target ECU  19  is a double-bank memory ECU with reference to  FIG. 147 . Also in this case, when the data verification value is used as determination information, the rewrite target ECU  19  computes a CRC value for each block of the program stored in the flash memory, collates the CRC value (CRC (B 1  to Bn)) for the old data attached to the received difference data and the CRC value (CRC (B 1 ′ to Bn′) for the new data with the computed CRC value, and determines the consistency of the difference data. When no new program is written in the flash memory, the received CRC value in all blocks matches the computed CRC value. In a case where writing is stopped in a state in which the new program is written up to m (&lt;n) blocks of the flash memory, and the writing is resumed, the computed CRC value matches the CRC value (CRC (B 1 ′ to Bn′) of the new data in the blocks  1  to m, and thus the rewrite target ECU  19  skips a write process (S 1706  and S 1707 ). The rewrite target ECU  19  performs the write process (S 1706  and S 1707 ) from the block m+1 by checking match with the CRC value (CRC (B 1  to Bn)) for the old data. 
     It is assumed that the bank-A of the flash memory is an active bank and has the version 2.0, the bank-B thereof is an inactive bank and has the version 1.0, and the difference data is difference data (difference data between the version 1.0 and the version 3.0) for updating the bank-B to the version 3.0. The difference data distributed from the CGW  13  is attached with data identification information (information indicating old (version 1.0)), a CRC value calculated for each block of the old data (old program (version 1.0)), and a CRC value computed for each block of the new data (new program (version 3.0)). 
     The rewrite specification data includes rewrite bank information indicating into which bank of the flash memory the difference data for the rewrite target ECU  19  is to be written. In a case where the rewrite bank information is used as determination information, the rewrite target ECU  19  collates the rewrite bank information acquired from the rewrite specification data with inactive bank information (bank-B) of the rewrite target ECU  19 , and determines the consistency of the difference data. In a case where the data identification information is used as determination information, the rewrite target ECU  19  collates the data identification information (old (version 1.0)) attached to the difference data with the data identification information (old) of the old program (version 1.0) stored in the inactive bank (bank-B) of the flash memory, and determines the consistency of the difference data. In a case where the data verification value is used as determination information, the rewrite target ECU  19  computes a CRC value for each block of the old program (version 1.0) stored in the inactive bank (bank-B) of the flash memory, collates the CRC value (CRC (B 1  to Bn)) attached to the difference data with the computed CRC value, and determines the consistency of the difference data. 
     In the examples illustrated in  FIGS. 143 and 144  described above, it has been described that the data identification information and the data verification value are attached to the difference data and are distributed from the CGW  13  along with the difference data. However, the data identification information and the data verification value may be attached as header information of the difference data, and the header information may be distributed to the rewrite target ECU  19  before the CGW  13  distributes the difference data to the rewrite target ECU  19 . When the header information is received from the CGW  13 , the rewrite target ECU  19  determines the consistency of the difference data by using the data identification information and the data verification value. 
     In  FIGS. 143 and 144 , the case where rewrite data is the difference data has been described as an example, but the same applies to a case where rewrite data is the entire data. In a case where the rewrite target ECU  19  has a single-bank memory, the same consistency determination is performed when the rollback difference data is used to return the memory to an original version. 
     As described above, the rewrite target ECU  19  performs the difference data consistency determination process, thus writes write data generated on the basis of the difference data only in a case where the consistency of the difference data is positive, and prevents a situation in which write data generated on the basis of the difference data is written in a case where the consistency of the difference data is negative. For example, in a case where difference data to be written into the bank-A is included in a distribution package for the rewrite target ECU  19  in which the bank-B of the flash memory is not an inactive bank, inconsistency can be detected before the difference data is written into the flash memory. In a case where difference data for other ECUs or difference data of which version is inconsistent is included in a distribution package as difference data for the rewrite target ECU, inconsistency can be detected before the difference data is written into the flash memory. 
     In a case where the rewrite target ECU  19  stops and then resumes writing of the write data, the rewrite target ECU  19  determines the consistency of the difference data on the basis of the data verification value for the stored data in the flash memory, and the data verification value of the old data and the data verification value of the new data associated with the received difference data. The rewrite target ECU  19  may determine the consistency of the difference data on the basis of the data verification value for the stored data and the verification value of the received new data, and may determine the consistency of the difference data on the basis of the data verification value for the stored data and the data verification value of the received old data from the final block for which a determination result is negative. 
     The rewrite target ECU  19  skips writing of the write data at least up to the preceding block of the final block for which the consistency of the difference data is determined as being negative, and resumes writing of the write data from the final block or the subsequent block of the final block. In a case where a block size is same as a data size of a write area for the write data, since writing of the write data has been completed up to the final block, it is sufficient to skip writing to the final block and resume writing from the final block. On the other hand, in a case where the block size is not the same as the data size of the write area for the write data, writing of the write data may be stopped in the final block, and thus it is necessary to resume writing from the final block. 
     (18) Rewrite Execution Control Process 
     The rewrite execution control process will be described with reference to  FIGS. 148 to 155 . The vehicle program rewriting system  1  executes the rewrite execution control process in the ECU  19 . 
     As illustrated in  FIG. 148 , the ECU  19  includes a program execution unit  104   a , a switching request receiving unit  104   b , a data acquisition unit  104   c , a bank information notification unit  104   d , a firmware acquisition unit  104   e , an installation execution unit  104   f , and an activation execution unit  104   g  in the rewrite execution control unit  104 . The program execution unit  104   a  rewrites an inactive bank by executing a rewrite program in an active bank while executing an application program and parameter data in the active bank. The switching request receiving unit  104   b  receives an activation request from the CGW  13 . The data acquisition unit  104   c  acquires write data for an area of the inactive bank that needs to be rewritten from the outside. The bank information notification unit  104   d  notifies the outside of double-bank rewrite information (hereinafter, referred to as bank information). The firmware acquisition unit  104   e  acquires firmware of a rewrite program from the outside. When an instruction for installation is given by the CGW  13 , the installation execution unit  104   f  writes write data into the flash memory and executes the installation. When an instruction for activation is given by the CGW  13 , the activation execution unit  104   g  executes the activation for switching the active bank in preparation for restart. 
     Next, an operation of the rewrite execution control unit  104  in the ECU  19  will be described with reference to  FIGS. 149 to 155 . The rewrite target ECU  19  executes a rewrite execution control program and thus performs the rewrite execution control process. The rewrite target ECU  19  performs a normal operation process, a rewrite operation process, an information notification process, and an application program verification process as the rewrite execution control process. Each process will be described below. In the present embodiment, a description will be made of a case where the rewrite target ECU  19  is a double-bank memory ECU or a single-bank suspend memory ECU. 
     (18-1) Normal Operation Process 
     The rewrite target ECU  19  initiates the normal operation process when the rewrite target ECU  19  transitions from the stop state or the sleep state to the active state due to turning-on of the IG power or the like. When the normal operation process is initiated, the rewrite target ECU  19  specifies an active bank on the basis of active bank determination information regarding the bank-A and the bank-B (S 1801 ), and is started with the active bank (S 1802 ). The rewrite target ECU  19  verifies the integrity of a program stored in the start bank (active bank), and determines whether the active bank is positive (S 1803 ). 
     When it is determined that a verification result of the integrity of the active bank is negative, and it is determined that the active bank is negative (S 1803 : NO), the rewrite target ECU  19  transmits error information indicating that the verification result of the integrity of the active bank is negative to the CGW  13  (S 1804 ), and finishes the normal operation process. When the error information is received from the rewrite target ECU  19 , the CGW  13  transmits the error information to the DCM  12 . When the error information is received from the CGW  13 , the DCM  12  uploads the received error information to the center device  3 . That is, when it is determined that the verification result of the integrity of the active bank is negative in the rewrite target ECU  19 , the CGW  13 , the DCM  12 , and the center device  3  are notified of this fact. 
     When it is determined that the verification result of the integrity of the active bank is positive, and it is determined that the active bank is positive (S 1803 : YES), the rewrite target ECU  19  verifies the integrity of the program stored in the rewrite bank (inactive bank), and determines whether or not the rewrite bank is positive (S 1805 ). 
     When it is determined that a verification result of the integrity of the rewrite bank is negative, and it is determined that a verification result of the rewrite bank is negative (S 1805 : NO), the rewrite target ECU  19  transmits error information indicating that the verification result of the integrity of the rewrite bank is negative to the CGW  13  (S 1806 ). When the error information is received from the rewrite target ECU  19 , the CGW  13  transmits the error information to the DCM  12 . When the error information is received from the CGW  13 , the DCM  12  uploads the received error information to the center device  3 . That is, when it is determined that the verification result of the integrity of the rewrite bank is negative in the rewrite target ECU  19 , the CGW  13 , the DCM  12 , and the center device  3  are notified of this fact. 
     The integrity verification process described above is executed by a boot program before an application program is executed. When the integrity verification is finished, the rewrite target ECU  19  specifies a location address of the boot vector table (S 1807 ), specifies a location address of the normal time vector table (S 1808 ), specifies a leading address of the application program (S 1809 ), executes the application program, and finishes the normal operation process. 
     (18-2) Rewrite Operation Process 
     When a rewrite request is received from the CGW  13 , the rewrite target ECU  19  initiates the rewrite operation process. When the rewrite operation process is initiated, the rewrite target ECU  19  performs authentication with the CGW  13  by using a security access key (S 1811 ). When it is determined that an authentication result is positive (S 1812 : YES), the rewrite target ECU  19  waits for write data to be received (S 1813 ). When it is determined that the write data has been received from the CGW  13  (S 1813 : YES), the rewrite target ECU  19  rewrites an application program located in a rewrite bank (inactive bank) while executing an application program located in a start bank (active bank) (S 1814 ). 
     It is determined whether or not rewriting of the application program has been completed (S 1815 ), and, when it is determined that rewriting of the application program has been completed (S 1815 : YES), the rewrite target ECU  19  determines whether or not verification is positive (S 1816 ). When it is determined that the verification is positive (S 1816 : YES), the rewrite target ECU  19  sets a rewrite completion flag to “OK” (S 1817 ). The verification is verification of the integrity of the application program written in the inactive bank. 
     The rewrite target ECU  19  determines whether or not an activation request has been received from the CGW  13  (S 1818 ). When it is determined that the activation request has been received from the CGW  13  (S 1818 : YES), the rewrite target ECU  19  increments, for example, a numerical value of active bank information regarding the rewrite bank, and thus updates the active bank information regarding the rewrite bank (S 1819 ). That is, update to information indicating that the rewrite target ECU will be started in the rewrite bank thereafter is performed. It is determined whether or not a version read signal has been received from the CGW  13  (S 1820 ), and, when it is determined that the version read signal has been received (S 1820 : YES), the rewrite target ECU  19  transmits, to the CGW  13 , version information regarding the active bank, version information regarding the inactive bank, and identification information for specifying which bank is the active bank (S 1821 ), and finishes the rewrite operation process. Here, the rewrite target ECU  19  may execute all of the processes from S 1811  to S 1821  according to the application program in the active bank (old bank) before switching. The rewrite target ECU  19  may execute the processes from S 1811  to S 1819  according to the application program in the active bank (old bank) before switching, and may be restarted after performing S 1819 , to execute the processes from S 1820  to S 1821  according to the application program in the active bank (new bank) after switching. 
     (18-3) Information Notification Process 
     The rewrite target ECU  19  initiates the information notification process when the rewrite target ECU  19  transitions from the stop state or the sleep state to the active state, or when, for example, the IG power is turned on or a notification request is received from the CGW  13 . When the information notification process is initiated, the rewrite target ECU  19  notifies the CGW  13  of identification information for uniquely specifying an application program and parameter data related to an active bank or an inactive bank and identification information for uniquely specifying a place where the active bank or the inactive bank is located on the memory. That is, the rewrite target ECU  19  acquires active bank information regarding an active bank (S 1831 ), and transmits the active bank information to the CGW  13  (S 1832 ). The rewrite target ECU  19  transmits, to the CGW  13 , information indicating which of the bank-A and the bank-B is the active bank, version information of the active bank, and the like as the active bank information. 
     When the transmission of the active bank information to the CGW  13  has been completed, the rewrite target ECU  19  acquires rewrite bank information (hereinafter, also referred to as bank information) regarding the rewrite bank (S 1833 ), and transmits the acquired rewrite bank information to the CGW  13  (S 1834 ). The rewrite target ECU  19  transmits, to the CGW  13 , information indicating which bank of the bank-A and the bank-B is the rewrite bank, version information of the rewrite bank, and the like as the rewrite bank information. When transmission of the rewrite bank information to the CGW  13  has been completed, the rewrite target ECU  19  transmits identification information for specifying location addresses of the active bank and the rewrite bank on the memory to the CGW  13  (S 1835 ), and finishes the information notification process. The rewrite target ECU  19  transmits, to the CGW  13 , for example, an initiation address and an end address of the bank-A and an initiation address and an end address of the bank-B in the flash memory as the identification information for specifying addresses. 
     (18-4) Rewrite Program Verification Process 
     When the rewrite program verification process is initiated, the rewrite target ECU  19  determines whether or not identification information for specifying an address for executing a rewrite program has been acquired (S 1841 ). When it is determined that the identification information for specifying the address for executing the rewrite program has been acquired (S 1841 : YES), the rewrite target ECU  19  determines whether or not the identification information matches the active bank information of the rewrite target ECU  19  (S 1842 ). Specifically, the rewrite target ECU  19  determines whether or not the bank information indicating the active bank in the active bank information matches the identification information. 
     When it is determined that the identification information matches the active bank information of the rewrite target ECU  19  (S 1842 : YES), the rewrite target ECU  19  acquires the rewrite program (S 1843 ), and determines whether or not identification information for specifying an address for rewriting the application program has been acquired (S 1844 ). Here, in a case of an embedded type configuration in which the rewrite program is embedded in the flash memory in advance, in S 1843 , the rewrite target ECU  19  acquires a write program in the active bank from the flash memory and executes the write program on the RAM. In a case of a download type configuration in which the rewrite program is not embedded in the flash memory in advance but is downloaded from the outside, in S 1843 , the rewrite target ECU  19  downloads the rewrite program to the RAM and executes the rewrite program. 
     When it is determined that the identification information for specifying the address for rewriting the application program has been acquired (S 1844 : YES), the rewrite target ECU  19  determines whether or not the identification information matches the active bank information of the rewrite target ECU  19  (S 1845 ). Specifically, the rewrite target ECU  19  determines whether or not bank information indicating the non-active bank in the active bank information matches the identification information. When it is determined that the identification information matches the active bank information of the ECU  19  (S 1845 : YES), the rewrite target ECU  19  rewrites the application program (S 1846 ), and finishes the rewrite program verification process. 
     When it is determined that the identification information does not match the active bank information of the ECU  19  do (S 1842 : NO), or it is determined that the identification information does not match the active bank information of the rewrite target ECU  19  (S 1845 : NO), the rewrite target ECU  19  determines that the application program or the parameter data is not executable in the active bank or the inactive bank, and transmits a negative acknowledgement to the CGW  13  (S 1847 ), and finishes the rewrite program verification process. For example, in the case of a double-bank memory ECU in which the bank-A of the flash memory is an active bank and the bank-B is an inactive bank, an address for executing a rewrite program is an address of the bank-A that is the active bank, and an address for rewriting an application program is an address of the bank-B that is the inactive bank. 
     As illustrated in  FIG. 150 , the rewrite target ECU  19  may acquire identification information for specifying an address from the CGW  13  before write data is acquired from the CGW  13 . As illustrated in  FIG. 151 , the rewrite target ECU  19  may acquire identification information for specifying an address when write data is acquired from the CGW  13 . The rewrite target ECU  19  receives rewrite specification data from the CGW  13 , for example, before write data is acquired, and acquires rewrite bank information. Since the rewrite bank information includes identification data for identifying which bank is an active bank and which bank is a rewrite bank, the identification data is used as identification information for specifying an address. 
     The rewrite target ECU  19  performs (18-2) the rewrite operation process described above in response to the CGW  13  performing an installation instruction process. Here, the installation instruction process performed by the CGW  13  will be described. 
     When the installation instruction process is initiated, the CGW  13  identifies the rewrite specification data (S 1851 ), and determines whether installation during is designated for all of the rewrite target ECUs  19 , installation during vehicle traveling is designated for all of the rewrite target ECUs  19 , or installation is designated for each memory type of the rewrite target ECU  19  (S 1852  to S 1854 ). 
     When it is determined that the installation during parking is designated for all of the rewrite target ECUs  19  (S 1852 : YES), the CGW  13  instructs the rewrite target ECU  19  to perform the installation on the condition that an approval for the installation has been obtained and the vehicle is parked (S 1855 ). When it is determined that the installation during vehicle traveling is designated for all of the rewrite target ECUs  19  (S 1853 : YES), the CGW  13  instructs the rewrite target ECU  19  to perform the installation on condition that an approval for the installation has been obtained and the vehicle is traveling (S 1856 ). 
     When it is determined that the installation is designated for each memory type of the rewrite target ECU  19  (S 1854 : YES), the CGW  13  determines whether the memory type is a double-bank memory, or a single-bank suspend memory or a single-bank memory on the basis of the rewrite specification data (S 1857  and S 1858 ). 
     When it is determined that the memory type of the rewrite target ECU  19  is the double-bank memory and satisfies a first predetermined condition (S 1857 : YES), the CGW  13  instructs the rewrite target ECU  19  to perform the installation on the condition that an approval for the installation has been obtained and the vehicle is traveling (S 1859 ). When it is determined that the memory type of the rewrite target ECU  19  is the single-bank suspend memory or the single-bank memory and satisfies a second predetermined condition (S 1858 : YES), the CGW  13  instructs the rewrite target ECU  19  to perform the installation on the condition that an approval for the installation has been obtained and the vehicle is parked (S 1860 ). 
     It is determined whether or not the installation has been completed in all of the rewrite target ECUs  19  (S 1861 ), and, when it is determined that the installation has not been completed in all of the rewrite target ECUs  19  (S 1861 : NO), the CGW  13  returns to step S 1851  and repeatedly performs step S 1851  and the subsequent steps. 
     That is, when the rewrite target ECU  19  is a double-bank memory ECU, the CGW  13  gives an instruction for the installation while the vehicle is ready to travel. The double-bank memory ECU is instructed to perform the installation from the CGW  13  while the vehicle is ready to travel, and thus performs the installation while the vehicle is ready to travel (corresponding to an installation execution procedure). When the rewrite target ECU  19  is a single-bank suspend memory ECU or a single-bank memory ECU, the CGW  13  gives an instruction for the installation during parking. The single-bank suspend memory ECU or the single-bank memory ECU is instructed to perform the installation during parking from the CGW  13  and thus performs the installation during parking (corresponding to an installation execution procedure). 
     When it is determined that the installation has been completed in all of the rewrite target ECUs  19  (S 1861 : YES), it is determined whether or not the vehicle is parked (S 1862 ), and, when, it is determined that the vehicle is parked (S 1862 : YES), the CGW  13  instructs the rewrite target ECU  19  to perform activation while the vehicle is parked (S 1863 ), and finishes the installation instruction process. The rewrite target ECU  19  is instructed to perform the activation from the CGW  13  while the vehicle is parked, and thus performs the activation (corresponding to an activation execution procedure). 
     As described above, the rewrite target ECU  19  performs the rewrite execution control process, and thus executes a rewrite program in an active bank and rewrites an inactive bank while an application program in the active bank is being executed in a configuration having a plurality of data storage banks. A period in which an application program is rewritable is not limited to a parking state, and the application program can be rewritten during vehicle traveling. When the rewrite target ECU  19  is a double-bank memory ECU, the rewrite target ECU  19  is instructed to perform installation from the CGW  13  while the vehicle is ready to travel, and can thus perform the installation while the vehicle is ready to travel. When the rewrite target ECU  19  is a single-bank suspend memory ECU or a single-bank memory ECU, the rewrite target ECU  19  is instructed to perform installation during parking from the CGW  13 , and can thus perform the installation during parking. 
     (19) Session Establishment Process 
     The session establishment process will be described with reference to  FIGS. 156 to 169 . The vehicle program rewriting system  1  performs the session establishment process in the rewrite target ECU  19 . 
     As illustrated in  FIG. 156 , the ECU  19  includes an application execution unit  105   a , a wireless rewrite request specifying unit  105   b , and a wired rewrite request specifying unit  105   c  in the session establishment unit  105 . The application execution unit  105   a  has a function of arbitrating execution of each program. The wireless rewrite request specifying unit  105   b  has a function of specifying a program rewrite request in a wireless manner. The wired rewrite request specifying unit  105   c  has a function of specifying a program rewrite request in a wired manner. 
       FIG. 157  illustrates a configuration of each program stored in the flash memory. A vehicle control program is a program for realizing a vehicle control function (for example, a steering control function) installed in the ECU  19 . A wired diagnosis program is a program for diagnosing the ECU  19  from the outside of the vehicle in a wired manner. A wireless diagnosis program is a program for diagnosing the ECU  19  from the outside of the vehicle in a wireless manner. A wireless rewrite program is a program for rewriting a program that is acquired from the outside of the vehicle in a wireless manner. A wired rewrite program is a program for rewriting a program that is acquired from the outside of the vehicle in a wired manner. The vehicle control program is located in the application area as a first program. The wired diagnosis program and the wired rewrite program are located in the application area as a second program. The wireless diagnosis program and the wireless rewrite program are located in the application area as a third program. In other words, the second program is a program for performing wired special processes except vehicle control, and the third program is a program for performing wireless special processes except the vehicle control. The wired rewrite program may not be located in the application area but may be located in the boot area as a fourth program. 
     The application execution unit  105   a  controls the first program, the second program, and the third program to be executable simultaneously (performs non-exclusive control). The application execution unit  105   a  makes, for example, the vehicle control program, the wired diagnosis program, and the wireless diagnosis program executable simultaneously. That is, the application execution unit  105   a  can simultaneously execute vehicle control, wired diagnosis of the ECU  19 , and wireless diagnosis of the ECU  19 . Similarly, the application execution unit  105   a  performs control such that the vehicle control program, the wired diagnosis program, and the wireless rewrite program can be executed simultaneously, the vehicle control program, the wired rewrite program, and the wireless diagnosis program can be executed simultaneously, and the vehicle control program, the wired rewrite program, and the wireless rewrite program can be executed simultaneously. 
     On the other hand, the application execution unit  105   a  performs exclusive control such that the respective programs in the second program cannot be executed simultaneously. Similarly, the application execution unit  105   a  performs exclusive control such that the respective programs in the third program cannot be executed simultaneously. The application execution unit  105   a  subjects, for example, the wired diagnosis program and the wired rewrite program to exclusive control, and subjects the wireless diagnosis program and the wireless rewrite program to exclusive control. That is, the application execution unit  105   a  executes only one program in the wired special processes. Similarly, the application execution unit  105   a  executes only one program in the wireless special processes. 
     In other words, it may be said that the wireless rewrite program is located inside the wireless diagnosis program and is embedded as a part of the wireless diagnosis program. That is, with the configuration in which the wireless rewrite program is located in the wireless diagnosis program, he application execution unit  105   a  performs control such that the wireless rewrite program is executed while continuing execution of the vehicle control program and the wired diagnosis program when a state transition is made from a default session or a wireless diagnosis session to a wireless rewrite session as will be described later while executing the vehicle control program and the wired diagnosis program. The application execution unit  105   a  initiates to execute the wireless rewrite program while continuing execution of the vehicle control program and the wired diagnosis program, and thus makes the vehicle control program, the wired diagnosis program, and the wireless rewrite program executable simultaneously. That is, the application execution unit  105   a  performs control such that vehicle control, wired diagnosis of the ECU  19 , and wireless rewriting of an application program can be executed simultaneously. 
     Here, a situation occurs in which wired diagnosis, wireless diagnosis, wired rewriting, and wireless rewriting cannot be executed simultaneously depending on specific contents of a diagnosis process and a rewrite process. For example, in a case where wired rewriting and wireless rewriting are rewriting of the same area, both of the processes collide with each other. Thus, the application execution unit  105   a  performs exclusive control on the wired diagnosis program and the wireless diagnosis program according to specific contents of a process or a request, and performs exclusive control on the wired rewrite program and the wireless rewrite program. Normal vehicle control may not be continued depending on contents of the diagnosis process. For example, in a case of the diagnosis process in which the ECU is operated and an operation result is read, the diagnosis process cannot be executed simultaneously with the normal vehicle control. In this case, the application execution unit  105   a  performs arbitration control of causing the vehicle control program to wait and executing the wired or wireless diagnosis program. 
     On the other hand, in a case where the wired rewrite program is not located in the application area but is located in the boot area as the fourth program, the application execution unit  105   a  performs arbitration control which is partially different from the above-described arbitration control. The wired rewrite program is located as the fourth program outside the wired diagnosis program as indicated by a dashed line in  FIG. 157 , and is not embedded as a part of the wired diagnosis program. In this case, when the fourth program is executed, the application execution unit  105   a  performs exclusive control so as to finish the first to third programs. That is, the application execution unit  105   a  switches from a mode of executing the first to third programs to a dedicated mode of executing the fourth program. In other words, regarding the wired rewrite program, with the configuration in which the wired rewrite program is located outside the wired diagnosis program, control is performed such that, when a state transition is made from the wired diagnosis session to the wired rewrite session as will be described later while the vehicle control program and the wireless diagnosis program are being executed, execution of the vehicle control program and the wireless diagnosis program is stopped, and execution of the wired rewrite program is initiated. The application execution unit  105   a  stops execution of the vehicle control program and the wireless diagnosis program and initiates execution of the wired rewrite program, and thus the vehicle control program, the wireless diagnosis program, and the wired rewrite program cannot be executed simultaneously, and only the wired rewrite program can be executed. That is, the application execution unit  105   a  performs control such that the vehicle control, the wireless diagnosis of the ECU  19 , and the wired rewriting of an application program cannot be executed simultaneously, and only wired rewriting of the application program can be executed. 
     As illustrated in  FIG. 158 , the application execution unit  105   a  manages a default state (default session), a wired diagnosis state (wired diagnosis session), and a wired rewrite state (wired rewrite session) as a first state related to the wired special processes. As a second state related to the wireless special processes, a default state (default session) and a wireless rewrite state (wireless rewrite session) are managed, and an internal operation state is managed. 
     As a state transition of the first state, the application execution unit  105   a  performs exclusive state transition among the default session in which vehicle control is possible in accordance with the diagnosis communication standard, the wired diagnosis session in which wired diagnosis of the ECU  19  is possible from the outside of the vehicle, and the wired rewrite session in which rewriting of an application program acquired from the outside of the vehicle in a wired manner is possible. The exclusive state transition of the session indicates that the sessions cannot be established simultaneously, and the non-exclusive state transition of the session indicates that the sessions can be established simultaneously. 
     The default session in the first state is a mode indicating a state in which the wired special process is not performed, and is a state in which vehicle control can be executed. It may also be said that the default session is a mode in which a process that does not influence the vehicle control at all, for example, a diagnosis program that is not related to the vehicle control, may be executed. The diagnosis program not related to the vehicle control is a program for reading information such as a trouble code. The wired diagnosis session is a mode of executing a diagnosis program related to diagnosis of the ECU  19 . In a case of the occurrence of a state in which at least the vehicle control may be influenced by executing the diagnosis program, the default session transitions to the wired diagnosis session. The diagnosis program related to diagnosis of the ECU  19  is a program for performing communication stoppage, diagnosis masking, actuator driving, and the like. The wired rewrite session is a mode of rewriting an application program acquired from the outside of the vehicle in a wired manner. 
     The application execution unit  105   a  performs the session state transition in the first state as follows. When a wired diagnosis request is generated in a state of a first default session, the application execution unit  105   a  makes a transition from the first default session to the wired diagnosis session in response to a diagnosis session transition request, and executes a wired diagnosis process. The application execution unit  105   a  makes a transition from the wired diagnosis session to the first default session when a session return request is generated, a timeout is generated, the power is turned off, or a legal service is received in a state of the wired diagnosis session. When a wired rewrite request is generated in a state of the first default session, the application execution unit  105   a  makes a transition from the first default session to the wired diagnosis session in response to a diagnosis session transition request, then makes a transition from the wired diagnosis session to the wired rewrite session in response to a rewrite session transition request, and executes a wired rewrite process. The application execution unit  105   a  makes a transition from the wired rewrite session to the first default session when a session restoration request is generated, a timeout is generated, the power is turned off, or a legal service is received in a state of the wired rewrite session. The application execution unit  105   a  maintains the current session without making a transition in response to a session maintenance request. 
     As a state transition of the second state, the application execution unit  105   a  makes an exclusive state transition between a default session in which the vehicle control is possible in accordance with the diagnosis communication standard and a wireless rewrite session related to rewriting of an application program acquired from the outside of the vehicle in a wireless manner. The wireless rewrite session is a mode of rewriting an application program acquired from the outside of the vehicle in a wireless manner. 
     The application execution unit  105   a  performs the session state transition in the second state as follows. When a wireless rewrite request is generated in a state of a second default session, the application execution unit  105   a  makes a transition from the second default session to the wireless rewrite session in response to a rewrite session transition request, and executes a wireless rewrite process. The application execution unit  105   a  makes a transition from the wireless rewrite session to the second default session when a session return request is generated, a timeout occurs, or the power is turned off in a state of the wireless rewrite session. The application execution unit  105   a  maintains the current session without making a transition in response to a session maintenance request. 
     The application execution unit  105   a  manages the first state related to the wired special process and the second state related to the wireless special process while executing the vehicle control program as the first program. For example, when a wired diagnosis request is generated in the default session in both of the first state and the second state, the application execution unit  105   a  causes the first state to transition to the wired diagnosis session while continuing the vehicle control program, and initiates execution of the wired diagnosis program. In this state, when a wireless rewrite request is generated, the application execution unit  105   a  causes the second state to transition to the wireless rewrite session while continuing execution of the vehicle control program and the wired diagnosis program, and initiates execution of the wireless rewrite program. In this state, when a wired rewrite request is generated, the application execution unit  105   a  finishes, for example, the execution of the wireless rewrite program, causes the second state to transition to the default session, finishes the execution of the wired diagnosis program, causes the first state to transition to the wired rewrite session, and initiates execution of the wired rewrite program. The application execution unit  105   a  performs an exclusive state transition such that the wired rewrite session in the first state and the wireless rewrite session in the second state are not established simultaneously, in order to prevent write processes in the same memory area from colliding with each other (exclusive control). 
     The wireless rewrite request specifying unit  105   b  determines identification information regarding a rewrite request received from the outside, and specifies a wireless rewrite request. That is, when reprogramming data is downloaded from the center device  3  to the DCM  12 , and the CGW  13  distributes the reprogramming data transferred from the DCM  12  to the rewrite target ECU  19 , the wireless rewrite request specifying unit  105   b  specifies the wireless rewrite request by receiving the identification information indicating the wireless rewrite request from the CGW  13  along with the reprogramming data. 
     The wired rewrite request specifying unit  105   c  determines identification information regarding a rewrite request received from the outside, and specifies a wired rewrite request. That is, when the tool  23  is connected to the DLC connector  22 , and the CGW  13  distributes reprogramming data transferred from the tool  23  to the rewrite target ECU  19 , the wired rewrite request specifying unit  105   c  specifies the wired rewrite request by receiving the identification information indicating the wired rewrite request along with the reprogramming data from the CGW  13 . 
     The identification information may be, for example, information corresponding to different identification IDs in the wired rewrite request and the wireless rewrite request, and may be information corresponding to the same identification ID but different data in the wired rewrite request and the wireless rewrite request. That is, any information may be used as long as the wired rewrite request and the wireless rewrite request can be differentiated from each other. 
     In the application execution unit  105   a , in  FIG. 158 , the configuration of managing the two states of the default session and the wireless rewrite session as the second state related to the wireless special process has been described, but, as illustrated in  FIGS. 159 and 160 , there may be a configuration of managing three states of the default session, the wireless diagnosis session, and the wireless rewrite session as the second state. The wireless diagnosis session is a mode of executing a wireless diagnosis program for diagnosing the ECU  19  from the outside of the vehicle in a wireless manner. In a case of executing a wireless diagnosis program that can influence at least the vehicle control, a transition is made to the wireless diagnosis session. 
     In a case of the configuration illustrated in  FIG. 159 , the application execution unit  105   a  performs a state transition of the second state as follows. When a wireless diagnosis request is generated in a state of the second default session, the application execution unit  105   a  makes a transition from the second default session to the wireless diagnosis session in response to a diagnosis session transition request, and executes a wireless diagnosis process. The application execution unit  105   a  makes a transition from the wireless diagnosis session to the second default session when a session return request is generated a timeout is generated, or the power is turned off in a state of the wireless diagnosis session. When a wireless rewrite request is generated in a state of the second default session, the application execution unit  105   a  makes a transition from the second default session to the wireless diagnosis session in response to a diagnosis session transition request, then makes a transition from the wireless diagnosis session to the wireless rewrite session in response to a rewrite session transition request, and executes a wireless rewrite process. The application execution unit  105   a  makes a transition from the wireless rewrite session to the second default session when a session return request is generated, a timeout is generated, or the power is turned off in a state of the wireless rewrite session. 
     In a case of the configuration illustrated in  FIG. 160 , the application execution unit  105   a  performs a state transition of the second state as follows. When a wireless diagnosis request is generated in a state of the second default session, the application execution unit  105   a  makes a transition from the second default session to the wireless diagnosis session in response to a diagnosis session transition request, and executes a wireless diagnosis process. The application execution unit  105   a  makes a transition from the wireless diagnosis session to the second default session when a session return request is generated a timeout is generated, or the power is turned off in a state of the wireless diagnosis session. When a wireless rewrite request is generated in a state of the second default session, the application execution unit  105   a  makes a transition from the second default session to the wireless diagnosis session in response to a diagnosis session transition request, then makes a transition from the wireless diagnosis session to the wireless rewrite session in response to a rewrite session transition request, or makes a transition from the second default session to the wireless rewrite session in response to the rewrite session transition request, and executes the wireless rewrite process. The application execution unit  105   a  makes a transition from the wireless rewrite session to the second default session when a session return request is generated, a timeout is generated, or the power is turned off in a state of the wireless rewrite session. 
     In the wired diagnosis session in the first state and the wireless diagnosis session in the second state, the same diagnosis program may be executed or different diagnosis programs may be executed. In the wired rewrite session in the first state and the wireless rewrite session in the second state, the same rewrite program may be executed or different rewrite programs may be executed. For example, a common rewrite program such as erasure or writing for a memory may be executed. 
     Arbitration of each session in the first state and each session in the second state in the configurations illustrated in  FIGS. 159 and 160  will be described. As described in  FIG. 157 , a description will be made of a case where the wired diagnosis program is located in the application area as the second program, the wireless diagnosis program and the wireless rewrite program are located in the application area as the third program, and the wired diagnosis program is located in the boot area as the fourth program. In other words, a description will be made of a configuration in which the wireless rewrite program is embedded as a part of the wireless diagnosis program, but the wired rewrite program is not embedded as a part of the wired diagnosis program. In this case, arbitration of program execution in each session in the first state and the second state is as illustrated in  FIG. 161 . 
     In a case where the second state is the wireless rewrite session and the first state is the default session, the application execution unit  105   a  executes the wireless rewrite program while executing the vehicle control program. In a case where the second state is the wireless rewrite session and the first state is the wired diagnosis session, the application execution unit  105   a  simultaneously executes the wireless rewrite program and the wired diagnosis program while executing the vehicle control program. 
     On the other hand, in a case where the first state is the wired rewrite session and the second state is the default session, the application execution unit  105   a  finishes the vehicle control program and executes only the wired rewrite program. In a case where the first state is the wired rewrite session and the second state is the wireless diagnosis session, the application execution unit  105   a  finishes the wireless diagnosis program and the vehicle control program, and executes only the wired rewrite program. That is, the application execution unit  105   a  exclusively controls the first to third programs as a dedicated mode of executing only the wired rewrite program that is the fourth program. 
     In a configuration in which the wired diagnosis program and the wired rewrite program are located in the application area as the second program, the arbitration of each program is partially different from that in  FIG. 161 . That is, in a configuration in which the wireless rewrite program is embedded as a part of the wireless diagnosis program and the wired rewrite program is embedded as a part of the wired diagnosis program, arbitration of program execution in each session in the first state and the second state is as illustrated in  FIG. 162 . In this case, when the first state is the wired rewrite session and the second state is the default session, the application execution unit  105   a  executes the wired rewrite program while executing the vehicle control program. In a case where the first state is the wired rewrite session and the second state is the wireless diagnosis session, the application execution unit  105   a  simultaneously executes the wired rewrite program and the wireless diagnosis program while executing the vehicle control program. 
     Next, an operation of the above-described configuration will be described with reference to  FIGS. 163 to 167 . In the ECU  19 , the microcomputer  33  executes a session establishment program and thus performs the session establishment process. 
     When the microcomputer  33  is started by detecting the supply of power, the microcomputer  33  executes the session establishment program to perform a state transition management process, and performs a state transition management process of managing a state transition of the first state and a state transition management process of managing a state transition of the second state. Each state transition management process will be described below. Here, a description will be made of a case where the application execution unit  105   a  manages the second state by using the configuration illustrated in  FIG. 158 , that is, the configuration having no wireless diagnosis session. 
     (19-1) State Transition Management Process of First State 
     When the microcomputer  33  is started by detecting the supply of power, and initiates the state transition management process of the first state, the microcomputer  33  determines a rewrite completion flag, and determines whether or not rewriting of the previous application program has been completed normally (S 1901 ). When it is determined that the rewrite completion flag is positive, and it is determined that rewriting of the previous application program has been completed normally (S 1901 : YES), the microcomputer  33  causes the first state to transition to the default session (S 1902 ). That is, the microcomputer  33  causes the first state to transition to the default session, and thus initiates the vehicle control process. 
     When the vehicle control process is initiated by executing the vehicle control program, while executing the vehicle control process, the microcomputer  33  determines whether or not a wired diagnosis request has been generated (S 1903 ), determines whether or not a wired rewrite request has been generated (S 1904 ), and determines whether a completion condition for the state transition management is established (S 1905 ). When it is determined that a wired diagnosis request has been generated (S 1903 : YES) while executing the vehicle control process, the microcomputer  33  causes the first state to transition from the default session to the wired diagnosis session (S 1906 ), and executes the wired diagnosis program to initiate the wired diagnosis process (S 1907 ). It is determined whether the completion condition for the wired diagnosis process is established (S 1908 ), and, when it is determined that the completion condition for the wired diagnosis process is established (S 1908 : YES), the microcomputer  33  finishes the wired diagnosis program to finish the wired diagnosis process (S 1909 ), and causes the first state to transition from the wired diagnosis session to the default session (S 1910 ). 
     When it is determined that a wired rewrite request has been generated (S 1904 : YES) while executing the vehicle control process, the microcomputer  33  initiates an exclusive rewrite process at the time of generation of a wired rewrite request (S 1911 ). That is, the process is a process for performing exclusive control such that the wired rewrite process and the wireless rewrite process do not collide with each other. When the exclusive rewrite process at the time of generation of the wired rewrite request is initiated, the microcomputer  33  determines whether or not a transition to the wireless rewrite session is in progress in the second state, that is, whether or not the second state is the wireless rewrite session (S 1921 ). When it is determined that the transition to the wireless rewrite session is not in progress in the second state (S 1921 : NO), the microcomputer  33  specifies that the first state can transition to the wired rewrite session (S 1922 ). The microcomputer  33  finishes the exclusive rewrite process at the time of generation of the wired rewrite request, and returns to the state transition management process of the first state. 
     When it is determined that the transition to the wireless rewrite session is in progress in the second state (S 1921 : YES), the microcomputer  33  determines whether or not to perform exclusive control by giving priority to either the wired rewrite session or the wireless rewrite session. Specifically, the microcomputer  33  determines whether or not any of a wired rewrite session priority condition, a wireless rewrite session priority condition, and a rewrite session priority condition during transition is established (S 1923  to S 1925 ). The wired rewrite session priority condition is a condition that the wired rewrite session is prioritized to the wireless rewrite session. The wireless rewrite session priority condition is a condition that the wireless rewrite session is prioritized to the wired rewrite session. The rewrite session priority condition during transition is a condition that a rewrite session during transition is prioritized, that is, a session of which a transition is performed earlier is prioritized. Which of these priority conditions is employed is set in advance, and, for example, a priority condition flag may be set for the vehicle, and the priority condition flag may be set for each rewrite ECU. 
     When it is determined that the wired rewrite session priority condition is established (S 1923 : YES), the microcomputer  33  causes the second state to transition from the wireless rewrite session to the default session in response to a session return request, stops the wireless rewriting (S 1926 ), and specifies that the first state can transition to the wired rewrite session (S 1922 ). The microcomputer  33  finishes the wireless rewrite program in accordance with the transition to the default session. The microcomputer  33  finishes the exclusive rewrite process at the time of generation of the wired rewrite request, and returns to the state transition management process of the first state. 
     When it is determined that the wireless rewrite session priority condition is established (S 1924 : YES), the microcomputer  33  discards the wired rewrite request and continues the wireless rewriting (S 1927 ). That is, the microcomputer  33  maintains the second state in the wireless rewrite session, continues to execute the wireless rewrite program, and specifies that the first state cannot transition to the wired rewrite session (S 1928 ). The microcomputer  33  finishes the exclusive rewrite process at the time of generation of the wired rewrite request, and returns to the state transition management process of the first state. 
     When it is determined that the rewrite session priority condition during transition is established (S 1925 : YES), also in this case, the microcomputer  33  discards the wired rewrite request and continues the wireless rewriting (S 1927 ). That is, the microcomputer  33  maintains the second state in the wireless rewrite session, continues to execute the wireless rewrite program, and specifies that the first state cannot transition to the wired rewrite session (S 1928 ). The microcomputer  33  finishes the exclusive rewrite process at the time of generation of the wired rewrite request, and returns to the state transition management process of the first state. The microcomputer  33  executes the exclusive rewrite process at the time of generation of the wired rewrite request as mentioned above, and thus the wired rewrite session and the wireless rewrite session are exclusively controlled not to be established simultaneously. 
     When the microcomputer  33  returns to the state transition management process of the first state, the microcomputer  33  determines whether or not the first state can transition to the wired rewrite session as a result of the exclusive rewrite process at the time of generation of the wired rewrite request (S 1912 ). When it is specified and thus determined that the first state can transition to the wired rewrite session through the exclusive rewrite process at the time of generation of the wired rewrite request (S 1912 : YES), the microcomputer  33  causes the first state to transition from the default session to the wired rewrite session via the wired diagnosis session (S 1913 ), stops the vehicle control process, and initiates the wired rewrite process (S 1914 ). The microcomputer  33  finishes the vehicle control program in accordance with the transition to the wired rewrite session. 
     It is determined whether the completion condition for the wired rewrite process is established (S 1915 ), and, when it is determined that a completion condition for the wired rewrite process is established (S 1915 : YES), the microcomputer  33  finishes the wired rewrite process (S 1916 ), and causes the first state to transition from the wired rewrite session to the default session (S 1917 ). Here, the completion condition for the wired rewrite process is, for example, a case where writing of the entire application program has been completed and integrity verification is executed. 
     When it is specified and thus determined that the first state cannot transition to the wired rewrite session through the exclusive rewrite process at the time of generation of the wired rewrite request (S 1912 : NO), the microcomputer  33  does not cause the first state to transition from the default session to the wired rewrite session via the wired diagnosis session. That is, the microcomputer  33  maintains the first state in the default session. When it is determined that a completion condition for the state transition management is established (S 1905 : YES), the microcomputer  33  completes the state transition management process of the first state. 
     In the above description, a description has been made of a case where, when it is determined that a transition to the wireless rewrite session is in progress in the second state in the exclusive rewrite process at the time of generation of the wired rewrite request, and it is determined that the wired rewrite session priority condition is established, the microcomputer  33  stops the wireless rewriting in the second state, but the microcomputer  33  may determine whether or not to stop the wireless rewrite session according to a non-rewritten remaining amount in the wireless rewriting. 
     When it is determined that the transition to the wireless rewrite session is in progress in the second state (S 1921 : YES), and it is determined that the wired rewrite session priority condition is established (S 1923 : YES), the microcomputer  33  determines whether or not a non-rewritten remaining amount in the wireless rewriting is equal to or larger than a predetermined amount (for example, 20% or more) in the wireless rewrite session during the transition (S 1931 ). When it is determined that the non-rewritten remaining amount in the wireless rewriting is equal to or larger than the predetermined amount (S 1931 : YES), the microcomputer  33  causes the second state to transition from the wireless rewrite session to the default session, and stops the wireless rewriting (S 1926 ). The microcomputer  33  finishes the wireless rewrite program in accordance with the transition to the default session. When it is determined that the non-rewritten remaining amount of the wireless rewriting is not equal to or larger than the predetermined amount (S 1931 : NO), the microcomputer  33  discards the wired rewrite request and continues the wireless rewriting (S 1927 ). That is, the microcomputer  33  stops the wireless rewrite session when the remaining time until completion of the wireless rewriting is relatively long, but does not stop and continues the wireless rewrite session when the remaining time until completion of the wireless rewriting is relatively short. 
     (19-2) State Transition Management Process of Second State 
     When the microcomputer  33  is started by detecting the supply of power, and initiates the state transition management process of the second state, the microcomputer  33  determines a rewrite completion flag, and determines whether or not rewriting of the previous application program has been completed normally (S 1941 ). When it is determined that the rewrite completion flag is positive, and it is determined that rewriting of the previous application program has been completed normally (S 1941 : YES), the microcomputer  33  causes the second state to transition to the default session (S 1942 ). That is, the microcomputer  33  causes the second state to transition to the default session, and thus executes the vehicle control program to initiate the vehicle control process. 
     When the vehicle control process is initiated, the microcomputer  33  determines whether or not a wireless rewrite request has been generated (S 1943 ), and determines whether a completion condition for the state transition management is established (S 1944 ). When it is determined that a wireless diagnosis request has been generated (S 1943 : YES) while executing the vehicle control process, the microcomputer  33  initiates an exclusive rewrite process at the time of generation of a wireless rewrite request (S 1944 ). When the exclusive rewrite process at the time of generation of the wireless rewrite request is initiated, the microcomputer  33  determines whether or not a transition to the wired rewrite session is in progress in the first state, that is, whether or not the first state is the wired rewrite session (S 1961 ). When it is determined that the transition to the wired rewrite session is not in progress in the first state (S 1961 : NO), the microcomputer  33  specifies that transition to the wireless rewrite session can occur (S 1962 ). The microcomputer  33  finishes the exclusive rewrite process at the time of generation of the wireless rewrite request, and returns to the state transition management process of the second state. 
     When it is determined that the transition to the wired rewrite session is in progress in the first state (S 1961 : YES), the microcomputer  33  determines whether or not to perform exclusive control by giving priority to either the wired rewrite session or the wireless rewrite session. Specifically, the microcomputer  33  determines whether or not any of a wireless rewrite session priority condition, a wired rewrite session priority condition, and a rewrite session priority condition during transition is established (S 1963  to S 1965 ). 
     When it is determined that the wireless rewrite session priority condition is established (S 1963 : YES), the microcomputer  33  causes the first state to transition from the wired rewrite session to the default session in response to a session return request, stops the wired rewriting (S 1966 ), and specifies that the second state can transition to the wireless rewrite session (S 1962 ). The microcomputer  33  finishes the wired rewrite program in accordance with the transition to the default session. The microcomputer  33  finishes the exclusive rewrite process at the time of generation of the wireless rewrite request, and returns to the state transition management process of the second state. 
     When it is determined that the priority condition for the wired rewrite session is established (S 1964 : YES), the microcomputer  33  discards the wireless rewrite request and continues the wired rewriting (S 1967 ). That is, the microcomputer  33  maintains the first state in the wired rewrite session, continues execution of the wired rewrite program, and specifies that the second state cannot transition to the wireless rewrite session (S 1968 ). The microcomputer  33  finishes the exclusive rewrite process at the time of generation of the wireless rewrite request, and returns to the state transition management process of the second state. 
     When it is determined that the rewrite session priority condition during transition is established (S 1965 : YES), also in this case, the microcomputer  33  discards the wireless rewrite request and continues the wired rewriting (S 1967 ). That is, the microcomputer  33  maintains the first state in the wired rewrite session, continues execution of the wired rewrite program, and specifies that the second state cannot transition to the wireless rewrite session (S 1968 ). The microcomputer  33  finishes the exclusive rewrite process at the time of generation of the wireless rewrite request, and returns to the state transition management process of the second state. The microcomputer  33  executes the exclusive rewrite process at the time of generation of the wireless rewrite request as mentioned above, and thus the wired rewrite session and the wireless rewrite session are exclusively controlled not to be established simultaneously. 
     When the microcomputer  33  returns to the state transition management process of the second state, the microcomputer  33  determines whether or not the second state can transition to the wireless rewrite session as a result of the exclusive rewrite process at the time of generation of the wireless rewrite request (S 1945 ). When it is specified and thus determined that the second state can transition to the wireless rewrite session through the exclusive rewrite process at the time of generation of the wireless rewrite request (S 1945 : YES), the microcomputer  33  causes the second state to transition from the default session to the wireless rewrite session (S 1946 ), and executes the wireless rewrite program to initiate the wireless rewrite process (S 1847 ). It is determined whether the completion condition for the wireless rewrite process is established (S 1948 ), and, when it is determined that a completion condition for the wireless rewrite process is established (S 1948 : YES), the microcomputer  33  finishes the wireless rewrite process (S 1949 ), and causes the second state to transition from the wireless rewrite session to the default session (S 1950 ). The microcomputer  33  finishes the wireless rewrite program in accordance with the transition to the default session. Here, the completion condition for the wireless rewrite process is, for example, a case where writing of the entire application program has been completed and the integrity verification is executed. 
     When it is specified and thus determined that the second state cannot transition to the wireless rewrite session through the exclusive rewrite process at the time of generation of the wireless rewrite request (S 1945 : NO), the microcomputer  33  does not cause the second state to transition from the default session to the wireless rewrite session. That is, the microcomputer  33  maintains the second state in the default session. When it is determined that a completion condition for the state transition management is established (S 1951 : YES), the microcomputer  33  finishes the state transition management process of the second state. 
     In the above description, a description has been made of a case where the application execution unit  105   a  can execute the program related to the wired special process and the program related to the wireless special process independently (simultaneously), but there may be a configuration in which the wired diagnosis program and the wireless diagnosis program are shared as illustrated in  FIG. 165 . In the configuration, the vehicle control program is located in the application area as the first program, and the diagnosis program (the wired diagnosis program and the wireless diagnosis program) and the wireless rewrite program are located in the application area as the second program. The wired rewrite program may be located in the application area as the second program, or may be located in the boot area as the third program. The application execution unit  105   a  simultaneously executes the first program and the second program. That is, the application execution unit  105   a  performs control such that the vehicle control program and the common diagnosis program can be executed simultaneously. On the other hand, the application execution unit  105   a  exclusively controls execution of each program forming the second program. That is, only one of the wired diagnosis program, the wireless diagnosis program, the wireless rewrite program, and the wired rewrite program is controlled to be operated. 
     As illustrated in  FIG. 166 , the application execution unit  105   a  manages the default state (default session), the diagnosis state (diagnosis session), the wired rewrite state (wired rewrite session), and the wireless rewrite state (wireless rewrite session) as the states, and manages an internal operation state. The states managed here are not managed independently in a wired and wireless manner, but are managed as one state in a mixed manner. 
     Also in this configuration, the application execution unit  105   a  initiates execution of the diagnosis program while executing the vehicle control program. The application execution unit  105   a  initiates execution of the wireless rewrite program or the wired rewrite program while executing the vehicle control program. On the other hand, the application execution unit  105   a  exclusively controls execution of the wireless diagnosis program and the wired diagnosis program. The application execution unit  105   a  also exclusively controls execution of the wired diagnosis program and the wireless diagnosis program, and the wired rewrite program and the wireless rewrite program. That is, the application execution unit  105   a  exclusively controls execution of each program forming the second program. 
     Here, in a case where the wired rewrite program is located in the boot area as the third program, the application execution unit  105   a  exclusively controls execution of the third program, and the first and second programs. That is, in a case where the wired rewrite program is executed, the first program and the second program are finished and are operated in a dedicated mode. 
     As illustrated in  FIG. 166 , when a diagnosis request is generated, the application execution unit  105   a  makes a transition to the diagnosis session while continuing execution of the vehicle control program, and initiates execution of the diagnosis program. In this state, when a wireless rewrite request is generated, the application execution unit  105   a  finishes the diagnosis program, makes a transition to the wireless rewrite session, and initiates execution of the wireless rewrite program. Execution of the vehicle control program is continued. On the other hand, in a case where a wired rewrite request is generated, the application execution unit  105   a  finishes the diagnosis program and the vehicle control program, makes a transition to the wired rewrite session, and initiates execution of the wired rewrite program. 
     Even when the wireless rewrite program is located inside the diagnosis program, the application execution unit  105   a  stops execution of the vehicle control program and the diagnosis program and then initiates execution of the wireless rewrite program when a state transition is made from the diagnosis session to the wireless rewrite session during execution of the vehicle control program and the diagnosis program. In a case where there is no session, the process can be continued. 
     When the wired rewrite program is located outside the diagnosis program, the application execution unit  105   a  stops execution of the vehicle control program and the wireless diagnosis program and initiates execution of the wired rewrite program when a state transition is made from the diagnosis session to the wired rewrite session during execution of the vehicle control program and the diagnosis program. That is, the application execution unit  105   a  performs control such that the vehicle control, the wired or wireless diagnosis of the ECU  19 , and the wired rewriting of an application program cannot be executed simultaneously, and only the wired rewriting of the application program can be executed. 
     As described above, the ECU  19  performs the session establishment process, thus executes the state transition management process of the first state and the state transition management process of the second state, manages a state transition of each session of the first state and the second state, and non-exclusively establishes the default session or the wired diagnosis session of the first state and the wireless rewrite session of the second state. The vehicle control program or the diagnosis program for the ECU  19  and the wireless rewrite program are controlled to be executed non-exclusively in response to requests for the vehicle control or the diagnosis of the ECU  19  and the wireless rewriting of a program, and thus it is possible to appropriately arbitrate various requests from the outside. 
     In the ECU  19 , the wired rewrite session and the wireless rewrite session are exclusively established. The wired rewrite program and the wireless rewrite program are controlled to be executed exclusively, and wired rewriting of the program and wireless rewriting of the program can be appropriately arbitrated. 
     In the ECU  19 , when the wired rewrite session priority condition is established, the wired rewrite session is prioritized to the wireless rewrite session. The wired rewrite session priority condition is set, and thus wired rewriting of the program can be executed prior to wireless rewriting of the program. For example, wired rewriting of a program for which an instruction is given by a maintenance person in a dealer or the like can be executed prior to wireless rewriting of the program for which an instruction is given by a user of a vehicle. 
     In the ECU  19 , the wireless rewrite session is prioritized to the wired rewrite session when the wireless rewrite session priority condition is established. The wireless rewrite session priority condition is set, and thus wireless rewriting of a program can be executed prior to wired rewriting of the program. For example, wireless rewriting of a program for which an instruction is given by a user of a vehicle can be executed prior to wired rewriting of the program for which an instruction is given by a maintenance person in a dealer or the like. 
     In the ECU  19 , when the rewrite session priority condition during transition is established, a rewrite session during transition is prioritized. The rewrite session priority condition during transition is set, and thus rewriting during transition can be preferentially executed. That is, one of wired rewriting and wireless rewriting, which has been initiated earlier, can be continued without stoppage. 
     In a configuration having double-bank application areas, the vehicle control program, the diagnosis program, and the wireless rewrite program are located in each application area, and the vehicle control program or the diagnosis program and the wireless rewrite program are executed in parallel (simultaneously). A memory configuration of the flash memory  30   d  is devised, and thus the vehicle control program or the diagnosis program and the wireless rewrite program can be executed in parallel. 
     When a wireless rewrite request is specified during execution of the vehicle control program or the wired diagnosis program, execution of the vehicle control program or the wired diagnosis program is continued, and the wireless rewrite program is executed. When a wireless rewrite request is generated during execution of the vehicle control program or the wired diagnosis program, the vehicle control program or the wired diagnosis program and the wireless rewrite program can be executed in parallel (simultaneously). 
     When a vehicle control request or a wired diagnosis request is specified during execution of the wireless rewrite program, execution of the wireless rewrite program is continued, and the vehicle control program or the wired diagnosis program is executed. When a vehicle control request or a wired diagnosis request is generated during execution of the wireless rewrite program, the wireless rewrite program and the vehicle control program or the wired diagnosis program can be executed in parallel (simultaneously). 
     When a wired rewrite request is specified during execution of while the vehicle control program or the wireless diagnosis program, execution of the vehicle control program or the wireless diagnosis program is stopped, and the wired rewrite program is executed. When a wired rewrite request is generated during execution of the vehicle control program or the wireless diagnosis program, only the wired rewrite program can be executed exclusively. 
     In a case of the reprogramming firmware embedded type in which reprogramming firmware is embedded, the rewrite program is executed by using the firmware located in the application area. It is possible to execute a rewrite process on an application program in an inactive bank without downloading the reprogramming firmware from the outside. 
     In a case of the reprogramming firmware download type in which reprogramming firmware is downloaded from the outside, the rewrite program is executed by using the firmware downloaded from the outside. It is possible to execute a rewrite process on an application program in an inactive bank after reducing a capacity of a rewrite program in the application area. 
     Although the double-bank memory having two tangible application areas has been described, the present embodiment is also applicable to a single-bank suspend memory or an external memory having two pseudo-application areas. 
     Although a description has been made of a case of difference rewriting in which new data is generated from old data and difference reprogramming data, the present embodiment is also applicable to a case of rewriting in which the entire new data is written by deleting old data. 
     Although a description has been made of a case where an application program of the ECU  19  is rewritten, the present embodiment is also applicable to a case of rewriting an application program of the CGW  13 . That is, the flash memory  26   d  of the CGW  13  may have a double-bank configuration equivalent to that of the flash memory  30   d  of the ECU  19 , and the microcomputer  26  may have a function equivalent to that of the microcomputer  33  of the ECU  19 . 
     (20) Retry Point Specifying Process 
     The retry point specifying process will be described with reference to  FIGS. 170 to 174 . The vehicle program rewriting system  1  performs the retry point specifying process in the rewrite target ECU  19 . The retry point is information indicating a portion corresponding to a completed process in order to resume stopped writing of write data halfway when writing of the write data is stopped in a case where the write data is written a plurality of times. As a case where writing of write data is stopped, for example, there is a case where cancellation occurs due to the user operation, a case where an abnormality such as communication disruption occurs, and a case where ignition switches from an OFF state to an ON state in a parking state. 
     In the ECU  19 , the program rewriting unit  102  shares a series of processes related to rewriting of an application program among a plurality of rewrite programs. The program rewriting unit  102  includes a first rewrite program for performing a first process and a second rewrite program for performing a second process, and sequentially executes the respective rewrite programs. The first process performed by the first rewrite program is, for example, a memory erasure process of erasing data in the flash memory and a data write process for writing write data. The second process performed by the second rewrite program is, for example, a verification process and a falsification check process. 
     As illustrated in  FIG. 170 , the ECU  19  includes a first process flag setting unit  106   a , a second process flag setting unit  106   b , and a retry point specifying unit  106   c  in the retry point specifying unit  106 . When the program rewriting unit  102  executes the first rewrite program, the first process flag setting unit  106   a  determines whether or not the program rewriting unit  102  has completed the first process by using the first rewrite program, and sets a first process flag indicating the determination result. When it is determined that the program rewriting unit  102  has completed the first process, the first process flag setting unit  106   a  sets the first process flag to “OK”. 
     When the program rewriting unit  102  executes the second rewrite program, the second process flag setting unit  106   b  determines whether or not the program rewriting unit  102  has completed the second process by using the second rewrite program, and sets a second process flag indicating the determination result. When it is determined that the program rewriting unit  102  has completed the second process, the second process flag setting unit  106   b  sets the second process flag to “OK”. 
     The retry point specifying unit  106   c  specifies a retry point when the program rewriting unit  102  retries rewriting of an application program according to the first process flag and the second process flag in a case where a part of the process related to the rewriting of the program is stopped. The retry point specifying unit  106   c  stores a write amount of update data until the stoppage, and requests the CGW  13  to transmit the update data on the basis of the stored write amount of the update data in a case where the process related to rewriting of the program is resumed. As illustrated in  FIG. 171 , the first process flag and the second process flag are stored in the same block of the flash memory of the rewrite target ECU  19 . 
     Next, an operation of the retry point specifying unit  106  in the rewrite target ECU  19  will be described with reference to  FIGS. 172 to 174 . The rewrite target ECU  19  executes a retry point specifying program and thus performs the retry point specifying process. The rewrite target ECU  19  performs a process flag setting process and a process flag determination process as the retry point specifying process. Each process will be described below. 
     (20-1) Process Flag Setting Process 
     When the process flag setting process is initiated, the rewrite target ECU  19  determines whether or not a pre-process before rewriting of an application program has been completed (S 2001 ). When it is determined that the pre-process before rewriting of the application program has been completed (S 2001 : YES), the rewrite target ECU  19  sets the first process flag to “NG”, sets the second process flag to “NG”, and stores the set process flags (S 2002 ; corresponding to a first process flag setting procedure and a second process flag setting procedure). 
     When write data is received from the CGW  13 , the rewrite target ECU  19  initiates the first process (S 2003 ) and determines whether or not the first process has been completed (S 2004 ). When it is determined that the first process has been completed (S 2004 : YES), the rewrite target ECU  19  sets the first process flag to “OK” in a state in which the second process flag is still set to “NG”, and stores the set first process flag (S 2005 ; corresponding to a first process flag setting procedure and a second process flag setting procedure). The rewrite target ECU  19  stores a write completion address indicating a portion where writing has been completed in the flash memory. 
     The rewrite target ECU  19  initiates the second process such as sending a write completion notification to the CGW  13  (S 2006 ), and determines whether or not the second process has been completed (S 2007 ). When it is determined that the second process has been completed (S 2007 : YES), the rewrite target ECU  19  sets the second process flag to “OK” and stores the set second process flag in a state in which the first process flag is still set to “OK” (S 2008 ; corresponding to a first process flag setting procedure and a second process flag setting procedure), and finishes the process flag setting process finishes. 
     (20-2) Process Flag Determination Process 
     When the rewrite target ECU  19  is started from the sleep state or the stop state, and the process flag determination process is initiated, the rewrite target ECU  19  is started by the boot program (S 2011 ), and reads the first process flag and the second process flag from the flash memory and determines the flags (S 2012  to S 2015 ). 
     When it is determined that the first process flag is set to “NG” and the second process flag is set to “NG” (S 2012 : YES), the rewrite target ECU  19  specifies a retry point at the beginning of the first process, notifies the CGW  13  of a retry request from the beginning of the first process (S 2016 ; corresponding to a retry point specifying procedure), and finishes the retry point specifying process. That is, the rewrite target ECU  19  requests the CGW  13  to distribute the write data. In this case, the rewrite target ECU  19  also notifies the CGW  13  of the write completion address read from the flash memory, and thus the CGW  13  specifies which of the write data to be divided and distributed will be distributed. When it is determined that the first process flag is set to “NG” and the second process flag is set to “OK” (S 2013 : YES), also in this case, the rewrite target ECU  19  specifies a retry point at the beginning of the first process (S 2016 ; corresponding to a retry point specifying procedure), notifies the CGW  13  of a retry request from the beginning of the first process (S 2017 ), and finishes the process flag determination process. 
     When it is determined that the first process flag is set to “OK” and the second process flag is set to “NG” (S 2014 : YES), the rewrite target ECU  19  specifies a retry point at the beginning of the second process (S 2018 ; corresponding to a retry point specifying procedure), notifies the CGW  13  of a retry request from the beginning of the second process (S 2019 ), and finishes the process flag determination process. The ECU  19  notifies the CGW  13  of, for example, up to which address the writing has been completed as the second process. 
     When it is determined that the first process flag is set to “OK” and the second process flag is set to “OK” (S 2015 : YES), the rewrite target ECU  19  notifies the CGW  13  of the completion of the process related to rewriting of the application program (S 2020 ), and finishes the process flag determination process. When the CGW  13  distributes divided write data, the rewrite target ECU  19  sets the above-described retry point in the unit of the divided write data. 
     As described above, the rewrite target ECU  19  performs the retry point specifying process, thus sets the first process flag indicating whether or not the first process has been completed, sets the second process flag indicating whether or not the second process has been completed, and specifies a retry point according to the first process flag and the second process flag. For example, in a case where the first process has been completed, and the rewrite target ECU  19  is restarted in a state in which the second process is not completed, the same write data can be prevented from being written again. 
     The rewrite target ECU  19  stores a data amount of the write data of which writing has been completed, that is, how many bytes of the write data have been written, and requests the CGW  13  to transmit the write data from the bytes in a case where writing of the write data is resumed. In a case where the rewrite target ECU  19  stores how many bytes of the write data have been written and resumes the writing, the rewrite target ECU  19  requests the CGW  13  to transmit the write data from the bytes. Therefore, at the time of resuming the writing, the CGW  13  can avoid waste of retransmitting the transmitted write data, and the rewrite target ECU  19  can write the write data from the next write area of a write area in which the write data has been written. The rewrite target ECU  19  that does not have the function of storing how many bytes of write data have been written requests the CGW  13  to transmit the write data from the leading write data in a case where writing of the write data is resumed. 
     (21) Progress State Synchronization Control Process 
     The progress state synchronization control process will be described with reference to  FIGS. 175 to 180 . The vehicle program rewriting system  1  performs a progress state synchronization control process in the CGW  13  and the center device  3 . The vehicle program rewriting system  1  includes the mobile terminal  6  and the in-vehicle display  7  as the display terminal  5  that allows a user to perform an input operation. The in-vehicle display  7  displays a progress screen indicating the progress of rewriting in cooperation with the CGW  13 . The mobile terminal  6  is connected to the center device  3 , and thus displays a progress screen indicating the progress of rewriting provided by the center device  3 . The CGW  13  and the center device  3  perform the progress state synchronization control process such that information displayed on the mobile terminal  6  and information displayed on the in-vehicle display  7  are synchronized with each other. 
     As illustrated in  FIG. 30  described above, for example, when the rewrite target ECU  19  is the ECU  19  equipped with a double-bank memory, procedures related to rewriting of an application program are performed in accordance with the campaign notification phase in which a user is notified of rewriting of the application program, and the user&#39;s approval is obtained, the download phase in which write data is downloaded from the center device  3  to the DCM  12 , the installation phase in which the write data is distributed from the CGW  13  to the rewrite target ECU  19 , and the activation phase in which an active bank at the next start switches from an old bank to a new bank. That is, the user operates the mobile terminal  6  or the in-vehicle display  7 , and thus causes a series of procedures related to rewriting of the application program to progress, for example, by approving execution of each phase. 
     As illustrated in  FIG. 175 , the CGW  13  includes a first progress state determination unit  88   a , a first progress state transmission unit  88   b , a second progress state acquisition unit  88   c , and a first display instruction unit  88   d  in the progress state synchronization control unit  88 . The first progress state determination unit  88   a  determines a first progress state related to rewriting of a program, and determines progress states, for example, the campaign notification phase, the download phase, the installation phase, and the activation phase. The campaign notification phase is a phase in which a campaign is received, the screens illustrated in  FIGS. 32 and 33  are displayed, and the user&#39;s approval is obtained. The download phase is a phase in which the screens illustrated in  FIGS. 34 to 37  are displayed, the user&#39;s approval is obtained, and download is executed. The installation phase is a phase in which the download has been completed, the screens illustrated in  FIGS. 38 to 42  are displayed, and installation is performed by obtaining the user&#39;s approval. The activation phase is a phase in which the screen illustrated in  FIG. 43  is displayed, the user&#39;s approval is obtained, and activation is executed. 
     The first progress state determination unit  88   a  specifies an operation performed by the user on the in-vehicle display  7  and determines a first progress state by transmitting a user operation signal from the in-vehicle display  7  to the CGW  13  when the user is riding on the vehicle and the user selects “approve execution of program update” on the in-vehicle display  7  and performs an operation for progress to the next phase. In this case, selecting “approve execution of program update” corresponds to operating any one of the “download initiation” button  503   a  illustrated in  FIG. 34 , the “immediate update” button  506   a  illustrated in  FIG. 39 , the “update reservation” button  506   b , and the “OK” button  508   b  illustrated in  FIG. 43 . When the first progress state is determined, the first progress state determination unit  88   a  manages the determined first progress state as the current progress state. 
     When the first progress state is determined by the first progress state determination unit  88   a , the first progress state transmission unit  88   b  transmits the determined first progress state to the center device  3 , and also transmits the determined first progress state to each in-vehicle display device such as the in-vehicle display  7 . The second progress state acquisition unit  88   c  acquires a second progress state related to the rewriting of the program from the center device  3 . When the first progress state is determined by the first progress state determination unit  88   a  and the second progress state is acquired by the second progress state acquisition unit, the first display instruction unit  88   d  gives an instruction for creation of contents displayable on the in-vehicle display  7  on the basis of the determined first progress state and the acquired second progress state. 
     Here, in a case where the second progress state acquisition unit  88   c  acquires the second progress state from the center device  3 , the first progress state determination unit  88   a  manages the second progress state as the current progress state when the second progress state is a phase earlier than the current progress state. That is, the first progress state is updated to a value of the second progress state. The first progress state transmission unit  88   b  transmits the first progress state that is the current progress state to the center device  3 . For example, in a case where the first progress state is a “download waiting phase” and a user approval operation is performed on the mobile terminal  6 , the second progress state acquisition unit  88   c  acquires a “download-in-progress phase” as the second progress state from the center device  3 . Since the “download-in-progress phase” acquired from the center device  3  is a phase earlier than the current progress state, the first progress state determination unit  88   a  updates the first progress state that is the current progress state to a value of the second progress state, transmits the updated first progress state to the center device  3 , and also transmits the updated first progress state to various in-vehicle display devices such as the in-vehicle display  7 . In addition to the “download-in-progress phase” as the first progress state, a “download completion X %” indicating the degree of progress of the download may be transmitted. 
     In a case where a user operation signal is generated in the in-vehicle display  7 , the first display instruction unit  88   d  gives an instruction for creation of contents on the basis of the first progress state determined by the first progress state determination unit  88   a . In a case where a user operation signal is generated in the mobile terminal  6 , the first display instruction unit  88   d  gives an instruction for creation of contents on the basis of the second progress state acquired by the second progress state acquisition unit  88   c . In a configuration in which the first progress state determined by the first progress state determination unit  88   a  is managed to be the current progress state at all times, that is, the master device  11  manages the current progress state, the first display instruction unit  88   d  may give an instruction for creation of contents on the basis of the first progress state. 
     As illustrated in  FIG. 176 , the center device  3  includes a second progress state determination unit  53   a , a second progress state transmission unit  53   b , a first progress state acquisition unit  53   c , and a second display instruction unit  53   d  in the progress state synchronization control unit  53 . The second progress state determination unit  53   a  determines the second progress state related to rewriting of a program, and determines the progress states, for example, the campaign notification phase, the download phase, the installation phase, and the activation phase. When the user is getting off (parking), selects “approve execution of program update” on the mobile terminal  6 , and performs an operation or progress to the next phase, the second progress state determination unit  53   a  receives a user operation signal transmitted from the mobile terminal  6  in an environment in which the mobile terminal  6  and the center device  3  can perform data communication with each other. 
     The second progress state determination unit  53   a  determines the second progress state on the basis of the current progress state that is the first progress state previously received from the master device  11  by the first progress state acquisition unit  53   c , and the user operation signal. For example, when the current progress state is an “installation waiting phase” and the user operation signal indicating “approval” is received, the second progress state determination unit  53   a  determines that the second progress state is an “installation-in-progress phase”. The second progress state determination unit  53   a  may determine “with user&#39;s approval in the installation waiting phase.” The user operation signal in the mobile terminal  6  is transmitted from the center device  3  to the DCM  12  in an environment in which the DCM  12  and the center device  3  can perform data communication with each other. The user operation signals is transferred from the DCM  12  to the CGW  13 , and thus the CGW  13  can determine the operation performed by the user on the mobile terminal  6  to determine the progress state. 
     When the second progress state is determined by the second progress state determination unit  53   a , the second progress state transmission unit  53   b  transmits the determined second progress state to the master device  11 . The first progress state acquisition unit  53   c  acquires the first progress state related to rewrite of the program from the master device  11 , and manages the first progress state as the current progress state. As the current progress state, the second progress state may be updated to a value of the first progress state. When the second progress state is determined by the second progress state determination unit  53   a  and the first progress state is acquired by the first progress state acquisition unit  53   d , the second display instruction unit  53   d  gives an instruction for creation of contents displayable on the mobile terminal  6  on the basis of the determined second progress state and the acquired first progress state. 
     For example, in a case where there is only a user operation signal in the mobile terminal  6 , the second progress state determined by the second progress state determination unit  53   a  and the first progress state acquired by the first progress state acquisition unit  53   d  indicate the same progress state. Therefore, the second display instruction unit  53   d  may give an instruction for creation of the contents on the basis of the second progress state. Thereafter, when the user operation signal is generated in the in-vehicle display  7 , the second display instruction unit  53   d  gives an instruction for creation of the contents on the basis of the acquired first progress state. 
     When an SMS is received as a progress state signal from the center device  3 , for example, the mobile terminal  6  is connected to the center device  3  when the user selects a URL described in the SMS, and displays a screen of a predetermined phase provided by the center device  3 . 
     Next, with reference to  FIGS. 177 to 180 , a description will be made of operations performed by the progress state synchronization control unit  88  in the CGW  13  and the progress state synchronization control unit  53  in the center device  3 . 
     As illustrated in  FIG. 177 , the master device  11  and the center device  3  transmit and receive a first progress state signal and a second progress state signal to cause synchronization in display of a progress state of a phase in the mobile terminal  6  and the in-vehicle display  7 . That is, when the first progress state that is the current progress state is updated, the master device  11  transmits the first progress state signal to the center device  3 , and also transmits the first progress state signal to various in-vehicle display devices such as the in-vehicle display  7 . The center device  3  transmits the first progress state signal as the current progress state to the mobile terminal  6 . Consequently, when the mobile terminal  6  can access the center device  3 , display of a progress state of a phase in the mobile terminal  6  and the in-vehicle display  7  is in synchronization. The center device  3  transmits the second progress state signal to the master device  11  on the basis of a user approval operation on the mobile terminal  6 , and thus causes synchronization in the display of the progress state of the phase in the mobile terminal  6  and the in-vehicle display  7  when the mobile terminal  6  can access the center device  3 . 
     The master device  11  which has acquired the second progress state signal may update the first progress state that is the current progress state, and then may transmit the first progress state to the center device  3  and each in-vehicle display device such as the in-vehicle display  7 . That is, the master device  11  transmits the current progress state to the center device  3  and each in-vehicle display device such as the in-vehicle display  7 , and thus functions as a phase management device. Here, the second progress state signal transmitted from the mobile terminal  6 , the in-vehicle display  7 , and the center device  3  may be a notification indicating any phase, or may be a notification indicating that a user approval operation has been performed or a notification indicating the meaning of an operated button. 
     When the progress state synchronization control process is initiated, the CGW  13  transmits distribution specification data to the in-vehicle display  7  (S 2101 ). The distribution specification data includes text or contents to be displayed to the user by the in-vehicle display  7 . The CGW  13  determines whether or not the user has performed an operation on the in-vehicle display  7  or the mobile terminal  6  on the basis of a notification from the in-vehicle display  7  or the center device  3  (S 2102 ). When it is determined that the user has performed the operation on the in-vehicle display  7  or the mobile terminal  6  (S 2102 : YES), the CGW  13  determines a phase corresponding to the operation on the basis of the first progress state (S 2103  to S 2106 ; corresponding to a first progress state determination procedure). 
     When the campaign notification phase is determined (S 2103 : YES), the CGW  13  performs a process in the campaign notification phase (S 2107 ), and transmits a first progress state signal indicating a progress state of the process in the campaign notification phase to the in-vehicle display  7  and the center device  3  (S 2111 ). The process in the campaign notification phase is, for example, a process of acquiring the user&#39;s input operation on the in-vehicle display  7  or the mobile terminal  6 . 
     The CGW  13  acquires, from the in-vehicle display  7  or the mobile terminal  6  via the center device  3 , for example, conditions such as a date and a place where a program is permitted to be executed, in addition to an approval or disapproval for update of the program. When information indicating that there is the user&#39;s input operation for an approval on the mobile terminal  6  is acquired from the center device  3  via the DCM  12 , the CGW  13  notifies the in-vehicle display  7  of the progress such as completion of the approval. On the other hand, when information indicating that there is the user&#39;s input operation for an approval on the in-vehicle display  7  is acquired from the in-vehicle display  7 , the CGW  13  notifies the center device  3  of the progress such as completion of the approval. 
     When the download phase is determined (S 2104 : YES), the CGW  13  performs a process in the download phase (S 2108 ), and transmits a first progress state signal indicating a progress state of the process in the download phase to the in-vehicle display  7  and the center device (S 2111 ). The process in the download phase is, for example, a process of calculating a percentage of completed download of a distribution package. 
     The CGW  13  determines the percentage of the completed download on the basis of a notification from the center device  3 . The CGW  13  notifies the in-vehicle display  7  and the center device  3  of the progress indicating the percentage of the completed download. The CGW  13  repeatedly performs the process until download of the distribution package is completed. When the download has been completed, the CGW  13  notifies the in-vehicle display  7  and the center device  3  of the progress indicating completion of the download phase. 
     When the installation phase is determined (S 2104 : YES), the CGW  13  performs a process in the installation phase (S 2108 ), and transmits a progress state signal indicating a progress state of the process in the installation phase to the in-vehicle display  7  and the DCM  12  (S 2111 ). The process in the installation phase is, for example, a process of calculating a percentage of completed installation in the rewrite target ECU  19 . 
     The CGW  13  determines the percentage of the completed installation on the basis of a notification from the rewrite target ECU  19 . The CGW  13  notifies the in-vehicle display  7  and the center device  3  of the progress indicating the percentage of the completed installation. The CGW  13  repeatedly performs the process until installation is completed in all of the rewrite target ECUs  19 . When the installation in all of the rewrite target ECUs  19  has been completed, the CGW  13  notifies the in-vehicle display  7  and the center device  3  of the progress indicating completion of the installation phase. 
     When the activation phase is determined (S 2104 : YES), the CGW  13  performs a process in the activation phase (S 2108 ), and transmits a progress state signal indicating a progress state of the process in the activation phase to the in-vehicle display  7  and the DCM  12  (S 2111 ; corresponding to a first progress state transmission procedure). The process in the activation phase is, for example, a process of calculating a percentage of completed activation in one or more rewrite target ECUs  19  belonging to the same group. The CGW  13  determines the percentage of the completed activation on the basis of a notification from the rewrite target ECU  19 . The CGW  13  notifies the in-vehicle display  7  and the center device of the progress indicating the percentage of the completed activation. 
     It is determined whether or not the activation phase has been completed (S 2112 ), and, when it is determined that the activation phase has been completed (S 2112 : YES), the CGW  13  finishes the progress state synchronization control process. When it is determined that the activation phase has not been completed (S 2112 : NO), the CGW  13  returns to S 2102 . The CGW  13  causes the process in each phase to progress and calculates a percentage of a completed process (S 2107  to S 2110 ). The CGW  13  periodically transmits the phase and information indicating that X % of a completed phase as the first progress state to the center device  3  (S 2111 ). 
     When the distribution specification data is transmitted and the progress state synchronization control process is initiated, the center device  3  monitors reception of the first progress state signal transmitted from the DCM  12  (S 2121 ). When it is determined that the first progress state signal has been received from the DCM  12  (S 2121 : YES), the center device  3  permits access from the mobile terminal  6  (S 2122 ), determines a phase specified by the first progress state signal (S 2123  to S 2126 ). 
     When the campaign notification phase is determined (S 2123 : YES), the center device  3  performs the process in the campaign notification phase (S 2127 ). That is, the center device  3  creates a campaign notification phase screen, transmits a display instruction signal for giving an instruction for display of the campaign notification phase screen to the mobile terminal  6 , and causes the mobile terminal  6  to display the campaign notification phase screen through connection to the center device  3 . 
     When the download phase is determined (S 2124 : YES), the center device  3  performs a process in the download phase (S 2128 ). That is, the center device  3  creates a download phase screen, transmits a display instruction signal for giving an instruction for display of the download phase screen to the mobile terminal  6 , and causes the mobile terminal  6  to display the download phase screen through connection to the center device  3 . When the center device  3  is notified of the progress indicating the percentage of the completed download from the DCM  12 , the center device  3  updates the download phase screen. 
     When the installation phase is determined (S 2125 : YES), the center device  3  performs a process in the installation phase (S 2129 ). That is, the center device  3  creates an installation phase screen, transmits a display instruction signal for giving an instruction for display of the installation phase screen to the mobile terminal  6 , and causes the mobile terminal  6  to display the installation phase screen through connection to the center device  3 . When the center device  3  is notified of the progress indicating the percentage of the completed installation from the DCM  12 , the center device  3  updates the installation phase screen. 
     When the activation phase is determined (S 2126 : YES), the center device  3  performs a process in the activation phase (S 2130 ). That is, the center device  3  creates an activation phase screen, transmits a display instruction signal for giving an instruction for display of the activation phase screen to the mobile terminal  6 , and causes the mobile terminal  6  to display the activation phase screen through connection to the center device  3 . When the center device  3  is notified of the progress indicating the percentage of the completed activation from the DCM  12 , the center device  3  updates the activation phase screen. When an operation such the user&#39;s approval is performed on the screens displayed in S 2127  to S 2130 , the center device  3  transmits a second progress state signal to the master device  11  (S 2131 ), and finishes the progress state synchronization control process. 
     When the distribution specification data is received from the CGW  13 , the in-vehicle display  7  initiates the progress display process, and monitors reception of the progress state signal transmitted from the CGW  13  (S 2141 ). When it is determined that the progress state signal has been received from the CGW  13  (S 2141 : YES), the in-vehicle display  7  permits the user operation on the in-vehicle display  7  (S 2142 ), determines a phase specified by the progress state signal (S 2143  to S 2146 ). 
     When the campaign notification phase is determined (S 2143 : YES), the in-vehicle display  7  displays a campaign notification phase screen by using text, contents, and the like included in the distribution specification data (S 2147 ). When the download phase is determined (S 2144 : YES), the in-vehicle display  7  displays a download phase screen (S 2148 ). The in-vehicle display  7  updates the download phase screen when notified of the progress indicating the percentage of completion of the download from the CGW  13 . 
     When it is determined that the in-vehicle display  7  is in the installation phase (S 2145 : YES), the installation phase screen is displayed (S 2149 ). When the in-vehicle display  7  is notified of the progress indicating the percentage of the completed installation from the CGW  13 , the in-vehicle display  7  updates the installation phase screen. When the activation phase is determined (S 2146 : YES), the in-vehicle display  7  displays an activation phase screen (S 2150 ). When the in-vehicle display  7  is notified of the progress indicating the percentage of the completed activation from the CGW  13 , the in-vehicle display  7  updates the activation phase screen. 
     As described above, the first progress state and the second progress state are transmitted and received between the master device  11  and the center device  3 . For example, even in a configuration in which the mobile terminal  6  is accessible to the center device  3  and the in-vehicle display  7  is inaccessible to the center device  3 , the first progress state and the second progress state are transmitted and received between the master device  11  and the center device  3 , and thus progress states or the like of rewriting of an application program can be appropriately synchronized among a plurality of display terminals. 
     (22) Display Control Information Transmission Control Process and (23) Display Control Information Reception Control Process 
     The display control information transmission control process in the center device  3  will be described with reference to  FIGS. 181 and 182 , and the display control information reception control process in the master device  11  will be described with reference to  FIGS. 183 to 185 . 
     As illustrated in  FIG. 181 , the center device  3  includes a write data storage unit  54   a  (corresponding to an update data storage unit), a display control information storage unit  54   b , and an information transmission unit  54   c  in the display control information transmission control unit  54 . The write data storage unit  54   a  stores write data for a plurality of rewrite target ECUs  19  with rewriting of application programs in the plurality of rewrite target ECUs  19  as a single campaign. The display control information storage unit  54   b  stores distribution specification data including display control information. The display control information is information required for display information related to rewriting of an application program in the rewrite target ECU  19  to be displayed on the in-vehicle display  7 , and is a display control program or property information. 
     The display information is data configuring various screens (a campaign notification screen, an installation screen, and the like) related to rewriting of the application program. The display control program is a program for realizing a function equivalent to that of a web browser. The property information is information defining display characters, display positions, colors, and the like. The information transmission unit  54   c  transmits the write data stored in the write data storage unit  54   a  and the display control information stored in the display control information storage unit  54   b  to the master device  11 . The information transmission unit  54   c  transmits the write data for the plurality of rewrite target ECUs  19  to the master device  11  as a single package. Here, the display control information may include phase identification information indicating a phase in which information is displayed. For example, the phase identification information indicates a phase in which information is displayed among the campaign notification phase, the download phase, the installation phase, and the activation phase. 
     Next, a description will be made of an operation performed by the display control information transmission control unit  54  in the center device  3  with reference to  FIG. 182 . The center device  3  executes a display control information transmission control program and thus performs the display control information transmission control process. 
     When the display control information transmission control process is initiated, the center device  3  transmits the distribution specification data to the CGW  13  via the DCM  12  (S 2201 ; corresponding to a control information transmission procedure), and transmits the write data to the CGW  13  via the DCM  12  (S 2202 ). The center device  3  transmits the display information to the CGW  13  via the DCM  12  (S 2203 ; corresponding to a display information transmission procedure), and finishes the display control information transmission control process. In a case where the display control information corresponding to each of the campaign notification phase, the download phase, the installation phase, and the activation phase is transmitted, the center device  3  may transmit the display control information corresponding to each phase to the in-vehicle display  7  in a single file, or may transmit the display control information corresponding to the next phase to the in-vehicle display  7  each time the phase is finished. Here, the timing at which the center device  3  transmits the distribution specification data may be configured to be transmitted in response to a request from the master device  11 . 
     As illustrated in  FIG. 183 , the CGW  13  includes an information receiving unit  89   a , a rewrite instruction unit  89   b , and a display instruction unit  89   c  in the display control information reception control unit  89 . The information receiving unit  89   a  receives the write data and the display control information from the center device  3 . When the write data is received from the center device  3  by the information receiving unit  89   a , the rewrite instruction unit  89   b  instructs the rewrite target ECU  19  to write the received write data. The display instruction unit  89   c  instructs the in-vehicle display  7  to display information regarding a campaign by using the display control information before the rewrite instruction unit  89   b  instructs the rewrite target ECU  19  to write the write data. The display instruction unit  89   c  may give an instruction for displaying the information regarding the campaign as history information after the entire write data is written. 
     Next, a description will be made of an operation performed by the display control information reception control unit  89  in the CGW  13  with reference to  FIG. 184 . The CGW  13  executes ae display control information reception control program and thus performs the display control information reception control process. consequently, in a case where the mobile terminal  6  and the in-vehicle display  7  are provided as display terminals, these display aspects can be brought close to each other, and thus the user&#39;s convenience can be improved. 
     When the display control information reception control process is initiated, the CGW  13  receives the distribution specification data from the center device  3  via the DCM  12  (S 2301 ; corresponding to a control information reception procedure). The write data is received from the center device  3  via the DCM  12  (S 2302 ). The CGW  13  receives the display information from the center device  3  via the DCM  12  (S 2303 ; corresponding to a display information reception procedure). The CGW  13  determines whether or not to use the display control information included in the distribution specification data from the center device  3  (S 2304 ). When it is determined that the display control information is to be used (S 2304 : YES), the CGW  13  instructs the in-vehicle display  7  to display the display information by using the display control information (S 2305 ). That is, the CGW  13  instructs the in-vehicle display  7  to display screens related to rewriting of an application programs by using the display control information. The in-vehicle display  7  displays the display information by using the display control information in response to the instruction from the CGW  13 . 
     When it is determined that the display control information is not to be used (S 2304 : NO), the CGW  13  instructs the in-vehicle display  7  to display the display information by using contents stored in advance (S 2306 ). That is, the CGW  13  instructs the in-vehicle display  7  to display screens related to rewriting of the application program by using the contents stored in advance. The in-vehicle display  7  displays the display information by using the contents stored in advance in response to the instruction from the CGW  13 . In a case where the display information corresponding to each of the campaign notification phase, the download phase, the installation phase, and the activation phase is displayed, the in-vehicle display  7  may collectively receive the display control information corresponding to each phase from the center device  3 , or may receive the display control information corresponding to the next phase from the center device  3  each time the phase is finished. 
     As illustrated in  FIG. 185 , when the in-vehicle display  7  does not have the function of a web browser, and the distribution specification data transmitted from the center device  3  to the in-vehicle display  7  via the DCM  12  and the CGW  13  includes property information but does not include a display control program, the in-vehicle display  7  displays the display information on a simple screen by using contents and frames stored in advance. The property information includes data such as text, its display position, its size, and the like, and is the same as the property information used in the screen created by the center device  3 . That is, although the screen image displayed on the in-vehicle display  7  differs from the screen image created by the center device  3  in terms of background, bit map, and the like, a display content is equivalent to that of the center device  3 . 
     When the in-vehicle display  7  does not have the function of a web browser, and the distribution specification data transmitted from the center device  3  to the in-vehicle display  7  via the DCM  12  and the CGW  13  includes the display control program and the property information, the in-vehicle display  7  displays the display information on a screen equivalent to that of the center device  3 . Here, the display control program and the property information included in the distribution specification data are the same as those used in the screen created by the center device  3 . 
     When the in-vehicle display  7  does not have the function of a web browser but stores the display control program, and the property information is included in the distribution specification data transmitted from the center device  3  to the in-vehicle display  7 , the in-vehicle display  7  displays the display information on a screen equivalent to that of the center device  3 . Here, the display control program stored in the in-vehicle display  7  is different in version from the display control program used in the screen created by the center device  3 , for example. 
     When the in-vehicle display  7  has the function of a web browser, the in-vehicle display  7  displays the display information on the same screen as that of the center device  3  through connection to the center device. 
     As described above, the center device  3  performs the display control information transmission control process, thus transmits the display control information to the in-vehicle display  7 , and displays the display information on the in-vehicle display  7  according to the display control information. Consequently, in a case where the mobile terminal  6  and the in-vehicle display  7  are provided as display terminals, these display aspects can be brought close to each other, and thus the user&#39;s convenience can be improved. The CGW  13  performs the display control information reception control process, thus receives the display control information from the center device  3 , receives the display information from the center device  3 , and displays the display information according to the display control information. 
     (24) Screen Display Control Process for Progress Display 
     The progress display screen display control process will be described with reference to  FIGS. 186 to 210 . The vehicle program rewriting system  1  performs the progress display screen display control process in the CGW  13 . 
     As illustrated in  FIG. 186 , the CGW  13  includes a mode determination unit  90   a  and a screen display instruction unit  90   b  in the progress display screen display control unit  90 . 
     The mode determination unit  90   a  determines whether or not a customization mode is set by the user&#39;s customization operation. The mode determination unit  90   a  determines whether or not an external mode from the outside is set on the basis of scene information included in the rewrite specification data. That is, the mode determination unit  90   a  refers to the scene information included in the rewrite specification data illustrated in  FIG. 8 . As illustrated in  FIGS. 8 and 187 , scene information, expiration date information, and position information are stored in the rewrite specification data. The scene information indicates a scene (for example, the type or a view) of the main update, and also designates screen display of the main update. Specifically, there are a recall flag, a dealer flag, a factory flag, a function update notification flag, and a forced execution flag. 
     The recall flag is a flag for designating screen display in a case where an application program is rewritten in response to a recall. The recall indicates implementation of measures such as repair, replacement, or recovery without charge due to the provisions of the regulations or at the discretion of a manufacturer or seller in a case where a defect in a product is found due to a design or manufacturing error, or the like. 
     The dealer flag is a flag for designating screen display in a case where an application program is rewritten in a dealer. The factory flag is a flag for designating screen display in a case where the application program is rewritten in a factory. The function update notification flag is a flag for designating screen display in a case where the application program is rewritten in response to a function update notification. The function update notification is performed to update a specific function. For example, the function update notification flag is a flag for designating screen display in the program update for adding a new function for a fee (or for free). 
     The forced execution flag is a flag for designating screen display in a case where the application program is rewritten in response to forced execution. The forced execution indicates that the application program is forced to be rewritten because campaign notifications are performed a predetermined number of times but the application program is not rewritten. For example, the forced execution flag is a flag for designating screen display in a case where a program is forced to be updated. 
     The flags indicating the scene information are all set to 0 (flag is not established) in a case where there is no relevant item, and any thereof is set to 1 (flag is established) in a case where there is a relevant item. For example, the mode determination unit  90   a  determines that a recall mode is set when the dealer flag is established, determines that a dealer mode is set when the recall flag is established, determines that a factory mode is set when the factory flag is established, determines that a function update mode is set when the function update notification flag is established, and determines that a forced execution mode is set when the forced execution flag is established. 
     The expiration date information is information indicating the expiration date, and is information serving as a criterion for determining whether or not rewrite of the application program is to be executed. The CGW  13  executes rewriting of the application program when the current time is within the expiration date indicated by the expiration date information, and does not execute rewriting of the application program when the current time exceeds the expiration date indicated by the expiration date information. That is, after a distribution package is downloaded, the CGW  13  refers to the expiration date information when installing the program, and does not execute installation of the program and discards the distribution package when the current time exceeds the expiration date. 
     The position information is information indicating a position, is information serving as a criterion for determining whether or not rewriting of the application program is to be executed, and includes a permitted area and a prohibited area. In a case where the permitted area is designated as the position information, the CGW  13  executes rewriting of the application program when the current position of the vehicle is inside the permitted area indicated by the position information, and does not execute rewriting of the application program when the current position of the vehicle is outside the permitted area indicated by the position information. In a case where the prohibited area is designated as the position information, the CGW  13  executes rewriting of the application program when the current position of the vehicle is outside the prohibited area indicated by the position information, and does not execute rewriting of the application program when the current position of the vehicle is inside the prohibited area indicated by the position information. That is, after the distribution package is downloaded, the CGW  13  refers to the position information when installing a program, and does not execute installation of the program when the current position is outside the permitted area, and delays the installation until the vehicle enters the permitted area. 
     The screen display instruction unit  90   b  instructs the display terminal  5  to display a screen corresponding to rewriting of the application program. The screen display instruction unit  90   b  instructs the display terminal  5  to display the screen by giving an instruction for whether or not the screen corresponding to a rewriting phase of the application program is displayed, giving an instruction for whether or not items of the screen are displayed, and giving an instruction for changing display contents of the items of the screen. 
     A description will be made of the user&#39;s customization operation. Here, a screen displayed on the in-vehicle display  7  will be described, but the same applies to a screen displayed on the mobile terminal  6 . In a screen described later, a layout of the number, disposition, and the like of buttons may be other than the exemplified layout. When the user performs an operation of displaying a menu screen on the in-vehicle display  7 , the CGW  13  displays a menu selection screen  511  on the in-vehicle display  7  as illustrated in  FIG. 188 . In the menu selection screen  511 , the CGW  13  displays a “software update” button  511   a , an “update result check” button  511   b , a “software version list” button  511   c , an “update history” button  511   d , a “user information registration” button  511   e , and waits for the user operation. 
     When the user operates the “user information registration” button  511   e  in this state, the CGW  13  displays a user selection screen  512  on the in-vehicle display  7  as illustrated in  FIG. 189 . In the user selection screen  512 , the CGW  13  displays “user” buttons  512   a  to  512   c  and waits for the user operation. 
     When the user operates the “user” button  512   a  in this state, the CGW  13  displays a user registration screen  513  on the in-vehicle display  7 , as illustrated in  FIG. 190 . In the user registration screen  513 , the CGW  13  displays input fields of an mail address and VIN information (individual vehicle identification information) for registration of personal information, displays input fields of a credit card number and the expiration date for registration of accounting information, displays the “ON/OFF” buttons  513   a  to  513   d  for campaign notification, download, installation, and activation in relation to settings of rewriting of an application program, displays a “detailed information” button  513   e , and waits for the user operation. 
     The “ON/OFF” buttons  513   a  to  513   d  for a campaign notification, download, installation, and activation are buttons for selecting whether or not to display screens for a campaign notification, download, installation, and activation. Specifically, when a campaign notification is received, download is initiated, installation is initiated, and activation is initiated, the buttons are buttons that allow the user to select in advance whether or not to display the contents for requesting the user&#39;s approval. The “detailed information” button  513   e  is a button for registering the above-described expiration date information and position information. The information set by the user is transmitted to the center device  3  via the DCM  12 . In a case where the user sets the pieces of information on the mobile terminal  6 , the CGW  13  acquires the pieces of information from the center device  3  via the DCM  12 . 
     The user may set the corresponding “ON/OFF” buttons  513   a  to  513   d  to OFF in a case where the user feels the screens bothersome about a campaign notification, download, installation, and activation. The buttons are set to OFF, and display of the contents for requesting the user&#39;s approval is omitted. For example, in a case where the user does not feel bothersome about screen display of a campaign notification or activation, but feels bothersome about screen display of download or installation, the user may set the campaign notification to ON with the “ON/OFF” button  513   a , set the download to OFF with the “ON/OFF” button  513   b , set the installation to OFF with the “ON/OFF” button  513   c , and set the activation to ON with the “ON/OFF” button  513   d.    
     In this case, for example, when the campaign notification is set to ON, the download is set to OFF, the installation is set to OFF, and the activation is set to ON, the display terminal  5  displays a campaign notification screen, does not display a download approval screen and a download-in-progress screen, does not display an installation approval screen and the installation-in-progress screen, and displays an activation screen according to a rewriting phase of the application program. That is, in the campaign notification, download, installation, and activation phases, when a corresponding phase is set to ON, the user performs screen display of the phase set to ON, and, when a corresponding phase is set to OFF, the user does not perform screen display of the phase set to OFF. Therefore, screen display can be customized. The ON/OFF setting of the screen display may be set individually for each phase, or all phases may be collectively set at a time. 
     In a case where the user wants to register the expiration date, the permitted area, and the prohibited area, the user may set the expiration date, the permitted area, and the prohibited area by operating the “detailed information” button  513   e . The user can customize the expiration date for permitting rewriting of the application program as the expiration date information, and can customize the permitted area for permitting rewriting of the application program as the location information or the prohibited area for prohibiting the rewriting. 
     Next, an operation of the above-described configuration will be described with reference to  FIGS. 191 to 214 . The CGW  13  executes a progress display screen display control program and thus performs the progress display screen display control process. 
     When the progress display screen display control process is initiated, the CGW  13  determines whether or not the expiration date information is stored in the rewrite specification data and whether or not the expiration date information is set in the customization information (S 2401 ). When it is determined that the expiration date information is stored in the rewrite specification data (S 2401 : YES), the CGW  13  determines whether the current time satisfies the expiration date information (S 2402 ). In a case where the expiration date information stored in the rewrite specification data and the expiration date information set as the customization information are present, the CGW  13  determines whether both are satisfied. When it is determined that the current time exceeds the expiration date indicated by the expiration date information and the current time does not satisfy the expiration date information (S 2402 : NO), the CGW  13  finishes the progress display screen display control process. 
     When it is determined that the current time is within the expiration date indicated by the expiration date information and the current time satisfies the expiration date information (S 2402 : YES), the CGW  13  determines whether or not the scene information is stored in the rewrite specification data (S 2403 ). When it is determined that the scene information is stored in the rewrite specification data (S 2403 : YES), the CGW  13  determines that the external mode is set, proceeds to the display instruction process according to the set content in the scene information (S 2404 ), and instructs the in-vehicle display  7  to perform screen display corresponding to rewriting of the application program according to a mode of an established flag. For example, when the recall flag is established, the CGW  13  instructs the in-vehicle display  7  to perform screen display according to the recall mode during rewriting of the application program. For example, when the dealer flag is established, the CGW  13  instructs the in-vehicle display  7  to perform screen display according to the dealer mode during rewrite of the application program. 
     When it is determined that the scene information is not stored in the rewrite specification data (S 2403 : NO), the CGW  13  determines whether or not the customization mode is set through the user&#39;s customization operation (S 2405 ; corresponding to a customization mode determination procedure). When it is determined that the customization mode is set (S 2405 : YES), the CGW  13  proceeds to a display instruction process according to the set content in the customization operation (S 2406 ; corresponding to a screen display instruction procedure), and instructs the in-vehicle display  7  to perform screen display corresponding to rewriting of the application program according to the customization mode. 
     When it is determined that the customization mode is not set (S 2405 : NO), the CGW  13  proceeds to a display instruction process according to a set content in the initial setting (S 2407 ; corresponding to a screen display instruction procedure), and instructs the in-vehicle display  7  to perform screen display corresponding to rewriting of the application program according to the customization mode. That is, the CGW  13  preferentially applies the scene information stored in the rewrite specification data, and applies the customization mode when the scene information is not stored. When neither the scene information nor the customization mode is present, the initial setting is applied. Here, the initial setting is a preset value, and the initial setting is a setting of turning on all settings of, for example, a campaign notification, download, installation, and activation. 
     Next, the screen display instruction processes in S 2404 , S 2406 , and S 2407  will be described with reference to  FIG. 192 . Here, the screen display instruction process in the installation phase is exemplified, but the same applies to the other phases. When the CGW  13  proceeds to the display instruction process, the CGW  13  sets whether or not to display the screen (S 2411 ), sets whether or not to display items of a screen (S 2412 ), and gives an instruction for changing display contents of the items of the screen (S 2413 ). The CGW  13  transmits a screen display request notification to the DCM  12 , causes the DCM  12  to transmit a screen display request to the in-vehicle display  7  (S 2414 ), and waits for reception of an operation result information from the DCM  12  (S 2415 ). The operation result information is information indicating a button operated by the user. The CGW  13  may directly transmit the screen display request notification to the in-vehicle display  7  and receive the operation result information. 
     When it is determined that the operation result information is received from the DCM  12  by transmitting an operation result from the in-vehicle display  7  to the DCM  12  (S 2415 : YES), the CGW  13  checks an approval on the basis of the operation result information, and determines whether or not the user has approved rewriting of the application program (S 2416 ). 
     When it is determined that the user has approved rewriting of the application program (S 2416 : YES), the CGW  13  determines whether or not the rewrite specification data stores the position information (S 2417 ). When it is determined that the position information is stored in the rewrite specification data (S 2417 : YES), the CGW  13  determines whether or not the current position of the vehicle satisfies the position information (S 2418 ). S 2417  and S 2418  may be omitted in phases other than the installation phase. In a case where the position information is the permitted area, when the current position of the vehicle is inside the permitted area, the CGW  13  determines that the current position of the vehicle satisfies the position information (S 2418 : YES), and continues the rewriting of the application program (S 2419 ). 
     On the other hand, when the current position of the vehicle is outside the permitted area, the CGW  13  determines that the current position of the vehicle does not satisfy the position information, does not continue and stops the rewriting of the application program, and finishes the screen display instruction process. In a case where the position information is the prohibited area, when the current position of the vehicle is outside the prohibited area, the CGW  13  determines that the current position of the vehicle satisfies the position information (S 2418 : YES), continues the rewriting of the application program (S 2419 ), and finishes the screen display instruction process. When the current position of the vehicle is inside the prohibited area, the CGW  13  determines that the current position of the vehicle does not satisfy the position information, does not continue and stops the rewriting of the application program, and finishes the display instruction process. 
     A description will be made of the screen display request notification transmitted from the CGW  13  to the DCM  12  and the operation result information transmitted from the DCM  12  to the CGW  13 . As illustrated in  FIG. 193 , the screen display request notification transmitted from the CGW  13  to the DCM  12  includes a phase ID, a scene ID, and screen configuration information. The Phase ID is an ID for identifying each phase such as a campaign notification, download, installation, and activation. The scene ID is an ID for identifying the scene information illustrated in  FIG. 187 . The operation result information transmitted from the DCM  12  to the CGW  13  includes transmission source information, a phase ID, a scene ID, an operation result, and additional information. The CGW  13  collates the phase ID and scene ID stored in the screen display request notification with the phase ID and scene ID stored in the operation result information, and checks deviation or arbitration. 
     That is, when the phase ID and the scene ID stored in the screen display request notification transmitted to the DCM  12  matches the phase ID and the scene ID stored in the operation result information received from the DCM  12 , the CGW  13  determines that the screen display request notification and the operation result information are consistent with each other, the screen display request notification and the operation result information are not deviated from each other, and thus arbitration is not required to be performed. On the other hand, when the phase ID and the scene ID stored in the screen display request notification transmitted to the DCM  12  do not match the phase ID and the scene ID stored in the operation result information received from the DCM  12 , the CGW  13  determines that the screen display request notification and the operation result information are inconsistent with each other, the screen display request notification and the operation result information are deviated from each other, and thus arbitration is required to be performed. The CGW  13  arbitrates whether or not to perform a process according to the operation result information received from the DCM  12 . 
     The screen configuration information is information indicating configuration elements of a screen, and, as illustrated in  FIG. 194 , for example, in the activation approval screen  514 , there are six items such as a “campaign ID . . . ” button  514   a , an “update name A . . . ” button  514   b , an “update name B . . . ” button  514   c , a “details check” button  514   d , a “back” button  514   e , and an “OK” button  514   f . In this case, as illustrated in  FIG. 195 , when all of the six items of the screen configuration information are set to “display”, as illustrated in  FIG. 194 , all of the six items are displayed on the activation approval screen  514 . That is, the user can operate any of the “campaign ID . . . ” button  514   a , the “update name A . . . ” button  514   b , the “update name B . . . ” button  514   c , the “details check” button  514   d , the “back” button  514   e , and the “OK” button  514   f.    
     On the other hand, as illustrated in  FIG. 196 , when the “campaign ID . . . ” button  514   a , the “update name A . . . ” button  514   b , the “update name B . . . ” button  514   c , the “detailed information” button  514   d , and the “OK” button  514   f  are set to “display”, and the “back” button  514   e  is set to “non-display” among the six items of screen configuration information, the “campaign ID . . . ” button  514   a , the “update name A . . . ” button  514   b , the “update name B . . . ” button  514   c , the “detailed information” button  514   d , and the “OK” button  514   f  are displayed and the “back” button  514   e  is not displayed on the activation approval screen  514 , as illustrated in  FIG. 197 . That is, the user can operate any of the “campaign ID . . . ” button  514   a , the “update name A . . . ” button  514   b , the “update name B . . . ” button  514   c , the “details check” button  514   d , the “OK” button  514   f , but the “back” button  514   e  is not displayed, and thus the “back” button  514   e  is not operable. For example, with respect to rewriting of an application program having a relatively high degree of importance or urgency due to a recall or the like, since it is not desirable to reject activation, setting can be made not to reject the activation by making the “back” button  514   e  inoperable as described above. In this case, the user approves the activation by operating the “OK” button  514   f.    
     A description will be made of a message framework regarding screen display and a user operation transmitted and received among the CGW  13 , the DCM  12 , the in-vehicle display  7 , the center device  3 , and a meter device  45 . As illustrated in  FIG. 198 , the CGW  13  and the DCM  12  are connected to each other via CAN or Ethernet, and the DCM  12  and the in-vehicle display  7  are connected to each other via the USB. 
     The CGW  13  performs data communication with the center device  3  via the DCM  12 . Data transmitted from the CGW  13  through diagnosis communication is subjected to protocol conversion by the DCM  12  and is received from the DCM  12  by the center device  3  through HTTP communication. For example, the CGW  13  transmits data indicating the current progress state such as the current phase or a progress ratio, to the center device  3  via the DCM  12 . The data transmitted from the center device  3  through HTTP communication is subjected to protocol conversion by the DCM  12  and is received from the DCM  12  by the CGW  13  through diagnosis communication. 
     The CGW  13  performs data communication with the in-vehicle display  7  via the DCM  12 . The data transmitted from the CGW  13  through the diagnosis communication is subjected to protocol conversion by the DCM  12  and is received from the DCM  12  by the in-vehicle display  7  through USB communication. The data transmitted from the in-vehicle display  7  through the USB communication is subjected to protocol conversion by the DCM  12  and is received from the DCM  12  by the CGW  13  through the diagnosis communication. For example, the CGW  13  acquires information regarding the user operation on the in-vehicle display  7  via the DCM  12 . As described above, in the vehicle program rewriting system  1 , the DCM  12  is provided with the protocol conversion function, and the mobile terminal  6  and the in-vehicle display  7  are configured to be equally handled by the CGW  13 . Information regarding the user operation is aggregated into the CGW  13 , and thus the CGW  13  arbitrates user operation results from a plurality of operation terminals so as to manage the current progress state. 
     A description will be made of a sequence of a message frame transmitted and received among the CGW  13 , the DCM  12 , and the in-vehicle display  7 . As illustrated in  FIGS. 199 to 206 , in the screen display request notification transmitted from the CGW  13  to the DCM  12  and the operation result information transmitted from the CGW  13  to the DCM  12 , the phase ID is set to “03” in the campaign notification, the phase ID is set to “04” in the download, the phase ID is set to “05” in the installation, and the phase ID is set to “06” in the activation. In each phase of the campaign notification, the download, the installation, and the activation, the order of transmission and reception of message frames is the same, and the phase IDs are different from each other such that the phases are differentiated from each other. 
       FIG. 199  exemplifies the campaign notification phase. The CGW  13  manages the current progress state, specifies the phase ID, the scene ID, and the screen configuration information, and transmits the screen display request notification to the DCM  12 . When the screen display request notification is received from the CGW  13 , the DCM  12  transmits a screen display request to the in-vehicle display  7 . When the screen display request is received from the DCM  12 , the in-vehicle display  7  displays a campaign notification screen, and, when the user performs an operation of checking the campaign notification, transmits the operation result to the DCM  12 . When the operation result is received from the in-vehicle display  7 , the DCM  12  transmits operation result information to the CGW  13 . The operation result information received by the CGW  13  includes transmission source information, a phase ID, a scene ID, the operation result, and additional information. The CGW  13  updates the current progress state on the basis of the operation result information received from the DCM  12 . Here, the CGW  13  updates the current progress state to the download phase when approval operations are performed in the campaign notification phase. 
       FIG. 200  exemplifies the download phase. The CGW  13  manages the current progress state, specifies the phase ID, the scene ID, and the screen configuration information, and transmits the screen display request notification to the DCM  12 . When the screen display request notification is received from the CGW  13 , the DCM  12  transmits a screen display request to the in-vehicle display  7 . When a screen display request is received from the DCM  12 , the in-vehicle display  7  displays a download approval screen, and, when the user performs a download approval operation, transmits the operation result to the DCM  12 . When the operation result is received from the in-vehicle display  7 , the DCM  12  transmits operation result information to the CGW  13 . The operation result information received by the CGW  13  includes transmission source information, a phase ID, a scene ID, the operation result, and additional information. The CGW  13  updates the current progress state on the basis of the operation result information received from the DCM  12 . Here, the CGW  13  updates the current progress state to the installation phase when there is an approval operation during the download phase. 
       FIG. 201  exemplifies the installation phase. The CGW  13  manages the current progress state, specifies the phase ID, the scene ID, and the screen configuration information, and transmits the screen display request notification to the DCM  12 . When the screen display request notification is received from the CGW  13 , the DCM  12  transmits a screen display request to the in-vehicle display  7 . When the screen display request is received from the DCM  12 , the in-vehicle display  7  displays an installation approval screen, and, when the user performs an installation approval operation, transmits the operation result to the DCM  12 . When the operation result is received from the in-vehicle display  7 , the DCM  12  transmits operation result information to the CGW  13 . The operation result information received by the CGW  13  includes transmission source information, a phase ID, a scene ID, the operation result, and additional information. The CGW  13  updates the current progress state on the basis of the operation result information received from the DCM  12 . Here, the CGW  13  updates the current progress state to the activation phase when there is an approval operation during the installation phase. 
       FIG. 202  exemplifies the activation phase. The CGW  13  manages the current progress state, specifies the phase ID, the scene ID, and the screen configuration information, and transmits the screen display request notification to the DCM  12 . When the screen display request notification is received from the CGW  13 , the DCM  12  transmits a screen display request to the in-vehicle display  7 . When the screen display request is received from the DCM  12 , the in-vehicle display  7  displays an activation approval screen, and, when the user performs an activation approval operation, transmits the operation result to the DCM  12 . When the operation result is received from the in-vehicle display  7 , the DCM  12  transmits operation result information to the CGW  13 . The operation result information received by the CGW  13  includes transmission source information, a phase ID, a scene ID, the operation result, and additional information. The CGW  13  updates the current progress state on the basis of the operation result information received from the DCM  12 . 
     The screen display will be described with reference to  FIGS. 203 to 210 . In a case where the customization mode is not set and no flag is set in the scene information of the rewrite specification data, the CGW  13  instructs the display terminal  5  to perform screen display corresponding to rewriting of the application program according to a content of the initial setting (S 2407 ). When the initial setting is a setting of turning on all of the campaign notification, the download, the installation, and the activations, the CGW  13  gives a screen display instruction to the display terminal  5  in order to sequentially display the navigation screen  501 , the campaign notification screen  502 , the download approval screen  503 , the download-in-progress screen  504 , the download completion notification screen  505 , the installation approval screen  506 , the installation-in-progress screen  507 , the activation approval screen  508 , the activation completion notification screen  509 , and the check operation screen  510 , as illustrated in  FIGS. 31 to 46 . In this case, the contents for obtaining the user&#39;s approval (OK) is displayed on the campaign notification screen  502 , the download approval screen  503 , the installation approval screen  506 , the activation approval screen  508 , and the check operation screen  510 . 
     In a case where the user&#39;s customization mode is set, the CGW  13  instructs the display terminal  5  to perform screen display corresponding to the rewriting of the application program according to a content of the customization mode (S 2406 ). However, this is limited to a case where scene information is not designated. For example, when the campaign notification is set to ON, the download is set to OFF, the installation is set to OFF, and the activation is set to ON in the customization mode, the CGW  13  gives a screen display instruction to the display terminal  5  in order not to display the download approval screen  503 , the download-in-progress screen  504 , the download completion notification screen  505 , the installation approval screen  506 , and the installation-in-progress screen  507  and to display the activation approval screen  508  after the campaign notification screen  502  is displayed. 
     In a case where the recall flag is set in the scene information of the rewrite specification data, the CGW  13  instructs the display terminal  5  to perform screen display corresponding to the rewriting of the application program according to a content of the recall mode (S 2404 ). In this case, as illustrated in  FIG. 204 , the CGW  13  does not display the “later” button  502   a  on the campaign notification screen  502 . As illustrated in  FIGS. 205 and 206 , the CGW  13  does not display the “back” button  503   c  on the download approval screen  503 . As illustrated in  FIG. 207 , the CGW  13  does not display the “back” button  504   b  on the download-in-progress screen  504 . As illustrated in  FIGS. 208 and 209 , the CGW  13  does not display the “back” button  505   b  on the installation approval screen  505 . Also, as illustrated in  FIG. 210 , the CGW  13  does not display the “back” button on the activation approval screen  518 . 
     That is, in a case where the recall flag is set in the scene information of the rewrite specification data, as described above, the “later” button or the “back” button may be set to non-display such that the “later” button or the “back” button is not displayed. Alternatively, after the campaign notification screen  502  may be displayed and the user&#39;s approval is obtained on the download approval screen  503 , display of the installation approval screen  505  and the activation approval screen  518  may be omitted. Although a case where the recall flag is set in the scene information of the rewrite specification data has been described above, the same applies to a case where the dealer flag, the factory flag, the function update notification flag, and the forced execution flag are set in the scene information of the rewrite specification data, and an instruction may be given for availability of display of a screen corresponding to a phase, availability of display of an item of the screen, or changing of a display content of the item of the screen depending on a situation in which the application program is rewritten. 
     Specifically, in a case where the dealer flag is set in the scene information of the rewrite specification data, since it is necessary to display a dedicated screen in the repair process in the dealer environment, a dedicated screen for a dealer may be displayed instead of a screen for a user. That is, since a user does not perform an operation related to rewriting of an application program, but a dealer&#39;s operator performs the operation related to the rewriting of the application program, the “later” button or the “back” button may be set to be displayed for the dealer&#39;s work, so that the “later” button or the “back” button is displayed. For example, a guidance such as “please rewrite in dealer” may be displayed to prompt the user to take the vehicle to the dealer. 
     In a case where the factory flag is set in the scene information of the rewrite specification data, screen display is not required in the manufacturing process in the factory environment, and thus a screen may not be displayed. 
     In a case where the function update notification flag is set in the scene information of the rewrite specification data, even when the user has customized the display unnecessary setting, a screen display for reliably notifying the user of the change content is required, so a screen for the user may be displayed regardless of the customized setting. That is, even in a case where the user determines that the approval is unnecessary, since it is desirable that the approval is forced to be obtained and an approval screen is forced to be displayed, as described above, the “later” button or the “back” button is set to display such that the “later” button or the “back” button is displayed. 
     In a case where the forced execution flag is set in the scene information of the rewrite specification data, even when the user sets display to be required through customization, and thus the user does not give an approval, forced execution for reliably updating software of the vehicle is required. Therefore, a dedicated screen for the user may be displayed regardless of the customization setting. That is, since the user determines that the approval is necessary, but the application program is rewritten even when the approval is not given, the “later” button or the “back” button may be set to non-display as described above such that the “later” button or the “back” button is not displayed. Since the function is based on an approval being obtained, rewriting may be performed by obtaining the approval without displaying the screen itself. 
     As described above, the CGW  13  performs the progress display screen display control process, and thus instructs the display terminal  5  to perform screen display corresponding to a setting content of a customization mode in a case where the customization mode is set. The user can customize screen display corresponding to the progress of rewriting. 
     (25) Program Update Notification Control Process 
     The program update notification control process will be described with reference to  FIGS. 211 to 217 . The vehicle program rewriting system  1  performs the program update notification control process in the CGW  13 . 
     As illustrated in  FIG. 211 , the CGW  13  includes a phase specifying unit  91   a , a display instruction unit  91   b , an indicator display control unit  91   c , an icon display control unit  91   d , a detailed information display control unit  91   e , and an cancellation instruction unit  91   f  in the program update notification control unit  91 . The phase specifying unit  91   a  specifies a phase as a progress situation of program update. The phase specifying unit  91   a  specifies campaign notification, download approval, download in progress, installation approval, installation in progress, activation approval, activation in progress, and update completion as phases of program update. 
     When the phase of the program update is specified by the phase specifying unit  91   a , the display instruction unit  91   b  gives an instruction for displaying an indicator in an aspect corresponding to the phase of the specified program update. When the instruction for displaying the indicator is given from the display instruction unit  91 , the indicator display control unit  91   c  controls display of the indicator in response to the instruction. Specifically, the indicator display control unit  91   c  controls lighting of an indicator  46  in the meter device  45 . 
     The icon display control unit  91   d  controls display of an icon on the in-vehicle display  7  following the indicator display control unit  91   c  controlling display of the indicator. The detailed information display control unit  91   e  controls display of an icon and detailed information related to the program update on the in-vehicle display  7  or the mobile terminal  6  following the indicator display control unit  91   c  controlling display of the indicator. The icon is the campaign notification icon  501   a  illustrated in  FIG. 32 , and the detailed information is, for example, the campaign notification screen  502  displayed in a pop-up form illustrated in  FIG. 33 , or the download approval screen illustrated in  FIGS. 34 and 35 . The detailed information display control unit  91   e  gives an instruction for displaying the icon in the aspect corresponding to the phase of the program update specified by the phase specifying unit  91   a , or gives an instruction for displaying the detailed information screen corresponding to the phase and the user operation. 
     The cancellatioin instruction unit  91   f  instructs the power supply management ECU  20  and the respective ECUs  19  related to the user operation to cancel reception of the user operation even in a case where the power supply management ECU  20  performs the power supply control by updating the programs during parking. For example, by instructing the engine ECU  47  (refer to  FIG. 217 ) to cancel reception of the user operation, in a case where a memory configuration of the rewrite target ECU  19  is a single-bank memory and the installation is performed during parking, the reception is cancelled and the engine is suppressed not to be started even when the user performs an operation of starting the engine. By instructing the power supply management ECU  20  to cancel the user operation, in a case where a memory configuration of the rewrite target ECU  19  is a single-bank memory, the IG power is turned on, installation is performed during parking, the reception is canceled and the IG power is suppressed not to be turned off even when the user performs an operation of turning off the IG power. In this case, the cancellation instruction unit  91   f  may instruct the in-vehicle display  7  to perform a notification that the reception of the user operation is invalidated. 
     Next, an operation of the above-described configuration will be described with reference to  FIGS. 212 to 217 . The CGW  13  executes a program update notification control program and thus performs the program update notification control process. 
     When the program update notification control process is initiated, the CGW  13  determines whether or not a campaign of program update has occurred (S 2501 ). When it is determined that the campaign of the program update has occurred (S 2501 : YES), the CGW  13  specifies a phase of the program update and a memory configuration (S 2502 ; corresponding to a phase specifying procedure). The CGW  13  instructs the meter device  45  to display the indicator  46  in an aspect corresponding to the specified phase of the program update (S 2503 ; corresponding to a display instruction procedure). The in-vehicle display  7  is instructed to display an icon corresponding to the specified phase of the program update (S 2504 ). 
     It is determined whether or not a detailed display request is available (S 2505 ), and, when it is determined that the detailed display request is available (S 2505 : YES), the CGW  13  determines whether or not data communication with the in-vehicle display  7  is possible (S 2506 ). For example, when the user presses the campaign notification icon  501   a  illustrated in  FIG. 32 , the “check” button  502   a  illustrated in  FIG. 33 , or the “details check” button  503   b  illustrated in  FIG. 34 , the CGW  13  determines that the detailed display request is available. When it is determined that data communication with the in-vehicle display  7  is possible (S 2506 : YES), the CGW  13  acquires detailed information (S 2507 ), instructs the in-vehicle display  7  to display the detailed information (S 2508 ), and instructs the center device  3  to display the detailed information (S 2509 ). 
     The CGW  13  acquires a notification content received along with the campaign notification and a notification content of the distribution specification data, and notifies the in-vehicle display  7  of the notification contents to be instructed to display the detailed information. The CGW  13  notifies the center device  3  of the phase and a content of the user operation as an instruction for displaying the detailed information such that the same content as that in the in-vehicle display  7  is also displayed on the mobile terminal  6 . 
     The CGW  13  determines whether or not an event of the program updating event is finished (S 2510 ). 
     For example, when the user confirms that the activation has been completed and the program has been updated, the CGW  13  determines that the event is finished. When it is determined that the event of the program update is not finished (S 2510 : NO), the CGW  13  returns to step S 2502  and repeatedly performs step S 2502  and the subsequent steps. The CGW  13  repeatedly performs S 2502  and the subsequent steps in each phase of the campaign notification, the download approval, the download in progress, the installation approval, the installation in progress, the activation approval, the activation in progress, and the update completion.
 
When it is determined that the event of the program update is finished (S 2510 : YES), the CGW  13  finishes the program update notification control process.
 
     In the meter device  45 , the indicator  46  is disposed at a predetermined position which can be recognized by the user, and, when a notification request notification is received from the CGW  13 , the indicator  46  is lighted or flashed as a notification during rewriting of the application program. Here, instead of the flashing, there may be the use of lighting display which is emphasized more than normal lighting display such as changing a color or increasing luminance of the indicator  46 . That is, any display may be used as long as the display is emphasized more than normal display. The indicator  46  related to program update is a single indicator and is formed of a single design. 
     As illustrated in  FIG. 213 , the meter device  45  changes notification aspects of the indicator in each phase in a case where an application program rewrite target is a double-bank memory, in a case where the application program rewrite target is a single-bank suspend memory, and in a case where the application program rewrite target is a single-bank memory. Specifically, the meter device  45  specifies a notification aspect of the indicator  46  according to a phase and a memory configuration designated from the CGW  13 , and performs a notification according to the specified notification aspect. Instead of the meter device  45 , the indicator display control unit  91   c  may control a notification aspect of the indicator  46 . The indicator display control unit  91   c  may specify a notification aspect of the indicator  46 , and instruct the meter device  45  to control lighting of the indicator  46  in the notification aspect. 
     As illustrated in  FIG. 213 , the indicator display control unit  91   c  flashes indicator  46  green, for example, in a phase where a restriction may occur in traveling of the vehicle, such as the installation or the activation. In a case where the rewrite target ECU  19  is a double-bank memory, the indicator display control unit  91   c  performs display in a flashing manner only in a phase in which activation is in progress. In a case where the rewrite target ECU  19  has a single-bank suspend memory, the indicator display control unit  91   c  displays the indicator in a flashing manner in the installation-in-progress phase during IG-off, the activation approval phase, and the activation-in-progress phase. In a case where the rewrite target ECU  19  has a single-bank memory, the indicator display control unit  91   c  displays the indicator in a flashing manner in the installation-in-progress phase, the activation approval phase, and the activation-in-progress phase. That is, the display of the indicator  46  in the campaign notification phase, the download phase, and the phase after the completion of activation (at IG-off, IG-on, and a check operation) is common regardless of memory configuration, but the display of the indicator  46  in the installation phase and the activation phase is performed in different aspects depending on a memory configuration. Here, the IG-off time illustrated in  FIG. 213  is a display aspect when the activation is executed during parking and the IG power is turned off due to completion of the activation, and the indicator  46  is lighted off when the IG power is turned off. Thereafter, when the IG power is turned on through the user operation, the indicator  46  is lighted. This is so that the user is notified of that the overall program update has been completed. When the user presses the “OK” button  510   b  on the check operation screen  510  illustrated in  FIG. 45 , it is determined that a check operation has been performed, and the indicator  46  is lighted off. 
     Hereinafter, a case where the meter device  45  controls a notification aspect of the indicator  46  will be described below, but the indicator display control unit  91   c  may control a notification aspect of the indicator  46  as described above.  FIG. 214  illustrates a notification aspect of the indicator in a case where the memory type of the rewrite target ECU  19  is a double-bank memory. The meter device  45  lights the indicator  46  in the phases from the campaign notification to the activation approval, and flashes the indicator  46  in the activation-in-progress phase, on the basis of instructions from the CGW  13 . Thereafter, the meter device  45  lights off the indicator  46  at IG-off, lights the indicator  46  at IG-on, and lights off the indicator  46  when the user performs a check operation for completion of the update. That is, in a case of the double-bank memory, there is a probability that the traveling of the vehicle may be restricted only during execution of activation. Only the execution of the activation is performed during a period in which the vehicle cannot travel because the vehicle is in a parking state. Thus, the meter device  45  flashes the indicator  46  in the activation-in-progress phase. Here, the indicator is a predetermined design, and is displayed green in a case of normal progress. 
       FIG. 215  illustrates a notification aspect of the indicator in a case where the memory type of the rewrite target ECU  19  is a single-bank suspend memory. In a case where an application program rewrite target is a single-bank suspend memory, the meter device  45  lights the indicator  46  in the phases from the campaign notification to the installation approval, lights the indicator  46  at IG-on during execution of the installation, and flashes the indicator  46  at IG-off, on the basis of instructions from the CGW  13 . That is, the meter device  45  lights the indicator  46  because writing into the flash memory of the single-bank suspend memory ECU is not executed in an IG ON state, but flashes the indicator  46  because writing into the flash memory is executed in an IG OFF state. The meter device  45  flashes the indicator  46  in the phases from the activation approval to the activation in progress. Thereafter, the indicator  46  is lighted off at IG-off, the indicator  46  is lighted in IG-on, and the indicator  46  is lighted off when the user performs a check operation for completion of the update. That is, in a case of the single-bank suspend memory, there is a probability that the traveling of the vehicle may be restricted from the installation in progress in an IG ON state to the activation in progress. Thus, the meter device  45  flashes the indicator  46  in these phases. Here, in a case of the single-bank suspend memory, even during the execution of the installation in an inactive bank, it is possible to start an active bank and control traveling of the vehicle by stopping the installation. Thus, as in a case of the double-bank memory, flashing display may be performed only during execution of the activation in which the vehicle cannot travel. 
       FIG. 216  illustrates a notification aspect of the indicator when the memory type of the rewrite target ECU  19  is a single-bank memory. In a case where an application program rewrite target is a single-bank memory, the meter device  45  lights the indicator  46  in the phases from the campaign notification to the installation approval, and flashes the indicator  46  in the phases from the installation in progress to the activation in progress, on the basis of instructions from the CGW  13 . Thereafter, the indicator  46  is lighted off at IG-off, the indicator  46  is lighted in IG-on, and the indicator  46  is lighted off when the user performs a check operation for completion of the update. That is, in a case of the single-bank memory, there is a probability that the traveling of the vehicle may be restricted from the installation in progress to the activation in progress. Thus, the meter device  45  flashes the indicator  46  in these phases. 
     In a case where the ECUs  19  having a double-bank memory, a single-bank suspend memory, and a single-bank memory are included as the program rewrite target ECUs  19  in one campaign notification, the meter device  45  performs rewriting of application programs on the ECUs  19  in an order of the double-bank memory, the single-bank suspend memory, and the single-bank memory. After the campaign notification, the CGW  13  performs the download approval to the installation in progress on the double-bank memory ECU  19 , and the meter device  45  lights the indicator  46  during this period. When the installation-in-progress phase on the double-bank memory ECU  19  is completed, the CGW  13  performs the download approval to the installation in progress on the single-bank suspend memory ECU  19 , and the meter device  45  lights the indicator  46  during this period. When the installation-in-progress phase on the single-bank suspend memory ECU  19  is completed, the CGW  13  performs the download approval to the installation approval on the single-bank memory ECU  19 , and the meter device  45  lights the indicator  46  during this period. 
     The meter device  45  flashes the indicators  46  from the installation in progress in the single-bank memory to the activation in progress in three types of the ECUs  19  of which the memory types are different from each other. The meter device  45  lights off the indicator  46  at subsequent IG-off, lights the indicator  46  at IG-on, and lights off the indicator  46  when the user performs a check operation for completion of the update. 
     The meter device  45  may perform the following control in a case where the ECUs  19  having a double-bank memory, a single-bank suspend memory, and a single-bank memory are included as the program rewrite target ECUs  19  in one campaign notification. The meter device  45  performs rewriting of application programs on the ECUs  19  in an order of the double-bank memory, the single-bank suspend memory, and the single-bank memory. After the campaign notification, the CGW  13  gives an instruction for lighting a predetermined green design as the indicator  46  in the download approval for download of a distribution package including update data of rewrite target ECUs  19  and the download in progress. Thereafter, the CGW  13  gives an instruction for lighting a predetermined green design as the installation approval indicator  46 . The installation approval here also serves as the activation approval for the convenience of including the single-bank memory ECU  19 . When the user&#39;s approval for the installation is obtained, the CGW  13  first performs installation on the double-bank memory ECU  19 . While the installation is performed in the double-bank memory ECU  19 , the meter device  45  lights the indicators  46 . When the CGW  13  completes the installation-in-progress phase for the double-bank memory ECU  19 , the CGW  13  performs installation on the single-bank suspend memory ECU  19 . While the installation is performed in the single-bank suspend memory ECU  19 , the meter device  45  lights the indicator  46 . When the CGW  13  completes the installation-in-progress phase for the single-bank suspend memory ECU  19 , the CGW  13  performs installation on the single-bank memory ECU  19 . While the installation is performed in the single-bank suspend memory ECU  19 , the meter device  45  flashes the indicator  46 . When the installation is completed in all of the rewrite target ECUs  19 , the CGW  13  performs activation in a state in which the indicator  46  is flashed. The CGW  13  instructs the meter device  45  to light off the indicator  46  at subsequent IG-off, instructs the meter device  45  to light the indicator  46  at IG-on, and instructs the meter device  46  to light off the indicator  46  when the user performs a check operation for completion of the update. 
     In the respective phases illustrated in  FIGS. 214 to 216 , the CGW  13  also instructs the in-vehicle display  7  to display icons. The CGW  13  gives an instruction for displaying the campaign notification icon  501   a  illustrated in  FIG. 32  in the campaign notification phase. The CGW  13  continues to display the campaign notification icons  501   a  even in the download approval phase. The CGW  13  gives an instruction for displaying the download-in-progress icon  501   b  illustrated in  FIG. 36  in the download-in-progress phase. In the installation approval phase, the CGW  13  may continue to display the download-in-progress icon  501   b  or may give an instruction for displaying the campaign notification icon  501   a  again. The CGW  13  gives an instruction for displaying the installation-in-progress icon  501   c  illustrated in  FIG. 41  in the installation-in-progress phase. In the activation approval phase, the CGW  13  may continue to display the installation-in-progress icon  501   c  or may give an instruction for displaying the campaign notification icon  501   a  again. The CGW  13  does not display the icons in the activation-in-progress phase and at subsequent IG-off. At IG-on, the CGW  13  may give an instruction for displaying the campaign notification icon  501   a  again, or may display the activation completion notification screen  509  in a pop-up form as illustrated in  FIG. 44 . The CGW  13  does not display the icons when the user performs a check operation for completion of the update. There is only one icon display related to the program update, and the icon display is formed of a design corresponding to each phase. 
     As described above, in a case where the CGW  13  gives an instruction for a notification that the application program is being rewritten by using the indicator  46 , when an abnormality occurs during rewriting of the application program, a notification aspect differs from that during the normal time. The CGW  13  gives an instruction for green lighting display or green flashing display, for example, when the rewriting of the application program is being performed normally, and gives an instruction for yellow or red lighting display or yellow or red flashing display, for example, when an abnormality occurs. The CGW  13  may change colors according to the degree of abnormality, give an instruction for red lighting display or red flashing display, for example, when the degree of abnormality is relatively high, and give an instruction for yellow lighting display or yellow flashing display when the degree of abnormality is relatively low. Here, the abnormality mentioned here includes a state in which a distribution package cannot be downloaded, a state in which write data cannot be installed, a state in which write data cannot be written in the rewrite target ECU  19 , a state in which write data is incorrect, and the like. 
     The in-vehicle display  7  sequentially displays the campaign notification screen  502 , the download approval screen  503 , the download-in-progress screen  504 , the download completion notification screen  505 , the installation approval  506 , the installation-in-progress screen  507 , the activation approval screen  508 , the IG-on screen  509 , and the update completion check operation screen  510  as detailed display on the basis of the user operation. The same detailed display as in the in-vehicle display  7  may be performed in the mobile terminal  6  that is communicatively connected to the center device  3 . For example, in a vehicle in which the in-vehicle display  7  is not mounted, in a case where the user requests the detailed display by operating a steering wheel switch or the like, the CGW  13  requests the detailed display to the center device  3  via the DCM  12 . The center device  3  creates content of the detailed display, and the mobile terminal  6  displays the content such that the user can check the detailed information on the mobile terminal  6 . 
     As illustrated in  FIG. 217 , in a case where an application program of a single-bank suspend memory or a single-bank memory of an IG ECU or an ACC ECU is rewritten during parking, the CGW  13  forcibly starts the power supply management ECU  20  to turn on the power of the vehicle. In this case, when the power supply management ECU  20  is forced to be started, the meter device  45  or the in-vehicle display  7  is started due to an operation of the power supply management ECU  20 . Thus, the CGW  13  instructs the meter device  45  or the in-vehicle display  7  to suppress a notification related to the program update. When the meter device  45  is instructed to suppress the notification of the update of the program from the CGW  13 , the meter device  45  does not light or flash the indicator  46 . When the in-vehicle display  7  is instructed to suppress the notification of the program update from the CGW  13 , the in-vehicle display  7  does not perform the above-described detailed display. That is, in a case of a situation in which the user is not riding in the installation or the activation performed during parking, since the notification related to the program update is unnecessary, the control is performed such that the notification is not performed. 
     When the power supply management ECU  20  is forced to be started to turn on the vehicle power, engine control is possible by receiving an operation on a push switch from the user, but the CGW  13  instructs the power supply management ECU  20  to invalidate reception of the user operation, and instructs the meter device  45 , the in-vehicle display  7 , and the ECU  19  related to the user operation to perform a notification of the cancellation of the reception of the user operation. In a case where the meter device  45  is instructed to invalidate the reception of the user operation from the CGW  13 , the meter device  45  invalidates the reception of the operation even when the user performs the operation on the meter device  45 . Similarly, in a case where the in-vehicle display  7  is instructed to invalidate the reception of the user operation from the CGW  13 , the in-vehicle display  7  invalidates the reception of the operation even when the user performs the operation on the in-vehicle display  7 . In a case where the engine ECU  47  is instructed to invalidate the reception of the user operation from the CGW  13 , the engine ECU  47  invalidates the reception of the operation to prevent the engine from being started even when the user performs the operation of starting the engine with the push switch. 
     As described above, the CGW  13  instructs the meter device  45  to perform a notification that an application program is being rewritten by performing the program update notification control process. Even in a situation where the user cannot be notified that an application program is being rewritten by using the mobile terminal  6  or the in-vehicle display  7 , the user can be appropriately notified that an application program is being rewritten by notifying the user that an application program is being rewritten by using the meter device  45 . The CGW  13  may change a notification aspect in accordance with a progress situation of rewriting of an application program. 
     (26) Self-Retention Power Execution Control Process 
     The self-retention power execution control process will be described with reference to  FIGS. 218 to 222 . The vehicle program rewriting system  1  performs self-retention power execution control process in the CGW  13 , the ECU  19 , the in-vehicle display  7 , and the power supply management ECU  20 . In this case, the CGW  13  gives an instruction for self-retention power to the ECU  19 , the in-vehicle display  7 , and the power supply management ECU  20 . That is, the CGW  13  corresponds to a vehicle master device, and the ECU  19 , the in-vehicle display  7 , and the power supply management ECU  20  correspond to vehicle slave devices. The CGW  13  has a second self-retention power circuit, the vehicle slave device has a first self-retention power circuit. 
     As illustrated in  FIG. 218 , the CGW  13  includes, in the self-retention power execution control unit  92 , a vehicle power determination unit  92   a , a rewrite-in-progress determination unit  92   b , a first self-retention power determination unit  92   c , a self-retention power instruction unit  92   d , a second self-retention power determination unit  92   e , a second self-retention power enable unit  92   f , a second stop condition establishment determination unit  92   g , and a second self-retention power stop unit  92   h.    
     The vehicle power determination unit  92   a  determines turning-on and turning-off of the vehicle power. The rewrite-in-progress determination unit  92   b  determines whether or not an application program is being rewritten. The rewrite-in-progress determination unit  95   b  also determines the rewrite target ECU  19  in which the application program is being rewritten. The first self-retention power enable unit  92   c  determines the necessity of self-retaining the power in the vehicle slave devices when it is determined by the vehicle power determination unit  92   a  that the vehicle power is turned off and it is determined by the rewrite-in-progress determination unit  92   b  that the program is being rewritten. That is, the first self-retention power enable unit  92   c  refers to the rewrite specification data illustrated in  FIG. 8 , and determines that the power needs to be self-retained when a rewrite method in the ECU information of the rewrite target ECU  19  is designated as the self-retention power method, and determines that the power does not need to be self-retained when the rewrite method is specified as the power supply control method. 
     When it is determined by the first self-retention power determination unit  92   c  that the power needs to be self-retained in the vehicle slave device, the self-retention power instruction unit  92   d  instructs the vehicle slave device to enable the first self-retention power circuit. As an aspect in which the self-retention power instruction unit  92   d  gives an instruction for enabling the first self-retention power circuit, there is an aspect of designating a completion time of the self-retention power, an aspect of giving an instruction for an extension time of the self-retention power, and an aspect of continuing to periodically output a self-retention request to the vehicle slave device. The self-retention power instruction unit  92   d  refers to the rewrite specification data illustrated in  FIG. 8 , and instructs the vehicle slave device to enable the first self-retention power circuit according to a time designated in the self-retention power time of the ECU information of the rewrite target ECU  19 . 
     That is, in the aspect of designating the completion time of the self-retention power, the self-retention power instruction unit  92   d  designates, as the completion time, the time obtained by adding the time designated in the rewrite specification data from the current time. In the case of designating the extension time of the self-retention power, the self-retention power instruction unit  92   d  designates the time specified in the rewrite specification data as the extension time. In the aspect of continuing to periodically output the self-retention request to the vehicle slave device, the self-retention power instruction unit  92   d  continues to periodically output the self-retention request to the vehicle slave device until the time specified in the rewrite specification data elapses. 
     The second self-retention power determination unit  92   e  determines the necessity of self-retaining the power therein when it is determined by the vehicle power determination unit  92   a  that the vehicle power is turned off and it is determined by the rewrite-in-progress determination unit  92   b  that the program is being rewritten. That is, the necessity of self-retaining the power is determined in consideration of a configuration in which the CGW  13  is an IG power system or an ACC power system. When it is determined by the second self-retention power determination unit  92   e  that it is necessary to self-retain the power supply therein, the second self-retention power enable unit  92   f  enables the second self-retention power circuit. 
     In this case, when the second self-retention power circuit is currently off, the second self-retention power enable unit  92   f  turns on the second self-retention power circuit and thus enables the second self-retention power circuit. In a case where the second self-retention power circuit is currently on, the second self-retention power enable unit  92   f  extends an operation period of the second self-retention power circuit, and thus enables the self-retention power circuit. 
     The second stop condition establishment determination unit  92   g  determines whether or not a stop condition for the self-retention power of the second self-retention power circuit is established. Specifically, the second stop condition establishment determination unit  92   g  monitors a remaining battery charge of the vehicle battery  40 , the occurrence of a timeout, and completion of rewriting in the rewrite target ECU  19 , and determines that the stop condition for the self-retention power of the second self-retention power circuit is estimated when it is determined that the remaining battery charge of the vehicle battery  40  is less than a predetermined capacity, the timeout occurs, or the rewriting in the rewrite target ECU  19  is completed. When it is determined by the second stop condition establishment determination unit  92   g  that the stop condition for the self-retention power of the second self-retention power circuit is established, the second self-retention power stop unit  92   h  turns off the second self-retention power circuit. 
     As illustrated in  FIG. 219 , the ECU  19  includes an instruction determination unit  108   a , a first self-retention power enable unit  108   b , a first stop condition establishment determination unit  108   c , and a first self-retention power stop unit  108   d  in the self-retention power execution control unit  108 . The instruction determination unit  108   a  determines whether or not an instruction for enabling the first self-retention power circuit has been given from the CGW  13 . 
     The first self-retention power enable unit  108   b  enables the first self-retention power circuit when it is determined by the instruction determination unit  108   a  that the instruction for enabling the first self-retention power circuit has been given. In a case where a completion time of the self-retention power is designated, the first self-retention power enable unit  108   b  enables the first self-retention power circuit until the designated completion time. In a case where an extension time of the self-retention power is designated, the first self-retention power enable unit  108   b  enables the first self-retention power circuit until the designated extension time elapses from the current time. In a case where a self-retention request is input from the CGW  13 , the first self-retention power enable unit  108   b  enables the first self-retention power circuit as long as the self-retention request is continuously input. 
     In this case, when the first self-retention power circuit is currently off, the first self-retention power enable unit  108   b  turns on the first self-retention power circuit and thus enables the first self-retention power circuit. In a case where the first self-retention power circuit is currently on, the first self-retention power enable unit  108   b  extends an operation period of the first self-retention power circuit, and thus enables the first self-retention power circuit. The first self-retention power enable unit  108   b  stores a default self-retention power time, and enables the first self-retention power circuit for the default self-retention power time even when an instruction for enabling the first self-retention power circuit is not given. That is, when the instruction for enabling the first self-retention power circuit is given, the first self-retention power enable unit  108   b  enables the first self-retention power circuit with priority to the longer time of the default self-retention power time and the self-retention power time based on the instruction from the CGW  13 . 
     The first stop condition establishment determination unit  108   c  determines whether or not a stop condition for the self-retention power of the first self-retention power circuit is established. Specifically, when a self-retention power target is the rewrite target ECU  19 , the first stop condition establishment determination unit  108   c  monitors the occurrence of a timeout and a stop instruction from the CGW  13 , and determines that the stop condition for the self-retention power of the first self-retention power circuit is established when it is determined that the timeout has occurred or the stop instruction from the CGW  13  has been received. When a self-retention power target is the in-vehicle display  7 , the first stop condition establishment determination unit  108   c  monitors the occurrence of a timeout, the user&#39;s getting-off, and a stop instruction from the CGW  13 , and determines that the stop condition for the self-retention power of the first self-retention power circuit is established when it is determined that the timeout has occurred, the user has gotten off, or the stop instruction has been received from the CGW  13 . When a self-retention power target is the power supply management ECU  20 , the first stop condition establishment determination unit  108   c  monitors a stop instruction from the CGW  13 , and determines that the stop condition for the self-retention power of the first self-retention power circuit is established when it is determined that the stop instruction from the CGW  13  has been received. The first self-retention power stop unit  108   d  turns off the first self-retention power circuit when it is determined by the second stop condition establishment determination unit  108   c  that the stop condition for the self-retention power of the first self-retention power circuit is established. 
     Next, an operation of the above-described configuration will be described with reference to  FIGS. 220 to 222 . Here, a description will be made of a case where the vehicle slave device is the rewrite target ECU  19 . Each of the CGW  13  and the rewrite target ECU  19  executes a self-retention power execution control program and thus performs the self-retention power execution control process. 
     When the self-retention power execution control process is initiated, the CGW  13  determines whether or not the vehicle power is turned off (S 2601 ; corresponding to a vehicle power determination step). When it is determined that the vehicle power is turned off (S 2601 : YES), the CGW  13  determines whether or not the application program is being rewritten (S 2602 ; corresponding to a rewrite-in-progress determination step). When it is determined that the application program is being rewritten (S 2602 : YES), the CGW  13  turns on the second self-retention power circuit (S 2603 ; corresponding to a second self-retention power enable step), and determines the necessity of self-retaining the power in the rewrite target ECU  19  (S 2604 ; corresponding to a self-retention power determination step). 
     When it is determined that it is necessary to self-retain the power in the rewrite target ECU  19  (S 2604 : YES), the CGW  13  instructs the rewrite target ECU  19  to enable the first self-retention power circuit (S 2605 ; corresponding to a self-retention power instruction step). It is determined whether or not a stop condition for the self-retention power is established (S 2606 ), and, when it is determined that the stop condition for the self-retention power is established (S 2606 : YES), the CGW  13  turns off the second self-retention power circuit (S 2607 ), and finishes the self-retention power execution control process. 
     Although the CGW  13  is configured to turn on the self-retention power circuit when it is determined that an application program is being rewritten, the CGW  13  may be configured to turn on the self-retention power circuit when it is determined that the vehicle power is turned off, and to extend an operation period of the self-retention power circuit that is currently on when it is determined that the application program is being rewritten. 
     When the self-retention power execution control process is initiated, the rewrite target ECU  19  determines whether or not the vehicle power is turned off (S 2611 ). When it is determined that the vehicle power is turned off (S 2611 : YES), the rewrite target ECU  19  turns on the self-retaining circuit (S 2612 ), determines whether or not a stop condition for the self-retention power is established (S 2613 ), and determines whether or not an instruction for enabling the self-retention power circuit has been given from the CGW  13  (S 2614 ). When it is determined that the instruction for enabling the self-retention power circuit has been given from the CGW  13  (S 2614 : YES), the rewrite target ECU  19  extends an operation period of the self-retention power circuit that is currently operating (S 2615 ). When it is determined that the stop condition for the self-retention power is established (S 2613 : YES), the rewrite target ECU  19  turns off the self-retention power circuit (S 2616 ), and finishes the self-retention power execution control process. 
     Although the rewrite target ECU  19  is configured to turn on the self-retention power circuit in a case where it is determined that the vehicle power is turned off, the rewrite target ECU  19  may be configured not to turn on the self-retention power circuit and to determine that the vehicle power is turned off in a case where it is determined that the vehicle power is turned off, and to turn on the self-retention power circuit that is currently off when it is determined that an instruction for enabling the self-retention power circuit is given from the CGW  13 . 
     The above description relates to a case where a vehicle slave device is the rewrite target ECU  19 , but the same applies to a case where a vehicle slave device is the in-vehicle display  7  or the power supply management ECU  20 . As illustrated in  FIG. 222 , in the rewrite target ECU  19 , the operation of the self-retention power circuit is required in a period from the preparation for installation to the post-rewrite process, and, in the in-vehicle display  7 , the operation of the self-retention power circuit is required in periods of waiting for update approval, waiting for download approval, waiting for installation approval, and waiting for activation approval. 
     As described above, by performing the self-retention power execution control process, when it is determined that the vehicle power is turned off and an application program is being rewritten, the CGW  13  determines the necessity of self-retaining the power in the rewrite target ECU  19 , and, when it is determined that it is necessary to self-retain the power, the CGW  13  instructs the rewrite target ECU  19  to enable the self-retention power circuit. When it is determined that an instruction for enabling the self-retention power circuit has been given from the CGW  13 , the rewrite target ECU  19  enables the self-retention power circuit. The self-retention power circuit is enabled such that operation power for rewriting the application program can be secured, and rewriting of the application program can be appropriately completed. 
     The overall sequence of program update including the above-described characteristic processes (1) to (26) will now be described with reference to  FIGS. 223 to 233 . Here, a description will be made of an example in which application programs of the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ) connected to the first bus are rewritten, and application programs of the ECU (ID 4 ), the ECU (ID 5 ), and the ECU (ID 6 ) connected to the second bus are not rewritten. The ECU (ID 1 ) and the ECU (ID 4 ) have single-bank memories, the ECU (ID 5 ) has a single-bank suspend memory, and the ECU (ID 2 ), the ECU (ID 3 ), and the ECU (ID 6 ) have double-bank memories. The ECU (ID 1 ), the ECU (ID 4 ), the ECU (ID 5 ), and the ECU (ID 6 ) are IG power ECUs, the ECU (ID 2 ) is an ACC power ECU, and the ECU (ID 3 ) is a +B power ECU. 
     First, as a preliminary preparation, the user operates the mobile terminal  6  or the like, inputs personal information such as a vehicle number (an identification number of a vehicle) or a mobile telephone number, and registers an account in the center device  3  (S 5001 ). Further, the user operates the mobile terminal  6  or the like, inputs execution conditions, and designates a vehicle position, a time period, or the like as conditions for permitting execution of program update. The center device  3  stores personal information or the like received via the mobile terminal  6  into a database (S 5002 ). 
     In the vehicle-side system  4 , the CGW  13  collects information regarding the vehicle (S 5011 ), and uploads the information to the center device  3  via the DCM  12  (S 5012 ). Specifically, the information includes a program version, a memory configuration of each ECU  19 , active bank information, electrical components mounted on the vehicle, a vehicle position, a vehicle power state, and the like. The center device  3  stores the information received from the vehicle-side system  4  into the database (S 5013 ). 
     When program update is necessary, the center device  3  generates the rewrite specification data illustrated in  FIGS. 7 and 8  including write data provided from a supplier that is a provider of an application program and the information stored in the database. The center device  3  generates reprogramming data including the write data, an authenticator thereof, and the rewrite specification data. The center device  3  packages the generated reprogramming data, the separately generated distribution specification data ( FIG. 9 ), and a package authenticator into one file, and generates and registers a distribution package (S 5021 ). 
     After the distribution package is prepared, the center device  3  notifies the user of program update. The center device  3  refers to the personal information stored in the database, and transmits a short message service (SMS) to the mobile terminal  6  (S 5031 ). The mobile terminal  6  is connected to a uniform resource locator (URL) described in the SMS through the user operation, and displays a notification content (S 5032 ). The mobile terminal  6  notifies the center device  3  of an approval or disapproval for the program update through the user operation (S 5033 ). The center device  3  registers the user&#39;s intention information (approval or disapproval) in the database (S 5034 ). Here, instead of the mobile terminal  6 , the user may be notified by using the in-vehicle display  7 . 
     The CGW  13  receives the distribution specification data transmitted from the center device  3  via the DCM  12 , and transfers the distribution specification data to the in-vehicle display  7  (S 5035 ). The in-vehicle display  7  analyzes the distribution specification data and displays a display wording or the like that is the notification content (S 5036 ). The in-vehicle display  7  displays image data such as icons and receives input as to whether or not the user approves the program update. The CGW  13  receives the user&#39;s intention information from the in-vehicle display  7  and notifies the center device  3  of the user&#39;s intention information via the DCM  12  (S 5037 ). 
     In a case where the approval for the program update is obtained from the user, the vehicle-side system  4  downloads the distribution package from the center device  3 . First, the center device  3  checks whether the execution conditions designated in advance for the user are satisfied (S 5041 ). In a case where at least one of the execution conditions is not satisfied, the center device  3  does not transmit the distribution package to the DCM  12 . In a case where all the execution conditions are satisfied, the center device  3  transmits the distribution packages to the DCM  12  (S 5042 ). When the distribution package is downloaded from the center device  3 , the DCM  12  stores the downloaded distribution package into the flash memory. The DCM  12  extracts the distribution package authenticator from the distribution package, and verifies the integrity of the reprogramming data and the distribution specification data (S 5043 ). 
     The DCM  12  calculates authenticators of the reprogramming data and the distribution specification data by using, for example, key information stored in the CGW  13 . The DCM  12  compares the calculated authenticators with the distribution package authenticator extracted from the distribution package, and determines that the verification is successful when the authenticators match each other, and determines that the verification fails when the authenticators do not match each other. When it is determined that the verification fails, the DCM  12  deletes the distribution package, and also notifies the CGW  13  and the center device  3  of the verification failure. 
     In a case where it is determined that the verification of the distribution package is successful, the DCM  12  unpackages the reprogramming data included in the distribution package as illustrated in  FIG. 10 , and divides the unpackaged reprogramming data into write data and rewrite specification data for each rewrite target ECU  19  (S 5044 ). The rewrite specification data is divided into DCM rewrite specification data and CGW rewrite specification data. 
     The DCM  12  transmits the CGW rewrite specification data to the CGW  13  (S 5045 ). The CGW  13  analyzes the CGW rewrite specification data received from the DCM  12 , extracts necessary information, and then authenticates the write data for each ECU  19  with the DCM  12  (S 5046 ). For example, the CGW  13  calculates an authenticator of the write data (difference data) of the ECU (ID 1 ) by using the key information of the ECU (ID 1 ) stored therein. The CGW  13  compares the calculated authenticator with the authenticator extracted from the reprogramming data, and determines that the verification is successful in a case where the authenticators match each other, and determines that the verification fails in a case where the authenticators do not match each other. When it is determined that the verification fails, the CGW  13  deletes the distribution package, and notifies the DCM  12  and the center device  3  of the verification failure. Here, in a case where it is determined that verification of any one of the pieces of write data fails, the CGW  13  does not perform program update on all the ECUs  19 . 
     When it is determined that all of the pieces of write data are successfully verified, the CGW  13  receives the distribution specification data from the DCM  12 , and transfers the received distribution specification data to the in-vehicle display  7  (S 5047 ). The in-vehicle display  7  stores the distribution specification data transferred from the CGW  13 . When the download process described above is completed, the CGW  13  notifies the center device  3  of download completion via the DCM  12  (S 5048 ). 
     When the center device  3  is notified of the download completion from the vehicle-side system  4 , the center device  3  transmits an SMS to the mobile terminal  6  (S 5049 ). The mobile terminal  6  is connected to a URL described in the SMS through the user operation, and displays an installation reservation screen (S 5050 ). The mobile terminal  6  notifies the center device  3  of the installation date and time entered through the user operation (S 5051 ). The center device  3  stores the installation date and time into the database in linking with the personal information (S 5052 ). Here, the user may be caused to reserve the installation date and time by using the in-vehicle display  7  instead of the mobile terminal  6 . When the in-vehicle display  7  is notified of the download completion from the CGW  13  (S 5053 ), the in-vehicle display  7  displays the installation reservation screen (S 5054 ). The CGW  13  notifies the center device  3  of the install date and time received from the in-vehicle display  7 , via the DCM  12  (S 5055 ). 
     In a case where the current date and time reaches the installation date and time registered in the database, the center device  3  instructs the vehicle-side system  4  to initiate installation (S 5071 ). When an instruction for the installation is given from the center device  3 , the DCM  12  checks installation execution conditions (S 5072 ). The DCM  12  checks, for example, a vehicle position or a status of communication with the center device  3 . In a case where all of the execution conditions are satisfied, the DCM  12  uses the package authenticator to authenticate the distribution package (S 5073 ). When the authentication is successful, the DCM  12  unpackages the distribution package (S 5074 ), extracts the DCM rewrite specification data and the CGW rewrite specification data, divides the rewrite specification data into pieces of write data for the respective ECUs  19 , and notifies the CGW  13  of installation initiation (S 5075 ). 
     When the CGW  13  is notified of the installation initiation from the DCM  12 , the CGW  13  analyzes the CGW rewrite specification data acquired from the DCM  12 , and determines an order of performing rewriting on the ECUs  19  (S 5076 ). Here, it is assumed that the ECU (ID 1 ) is subjected to rewriting first, the ECU (ID 2 ) is subjected to rewriting second, and the ECU (ID 3 ) is subjected to rewriting third. The CGW  13  verifies all the pieces of write data for the respective rewrite target ECUs  19  stored in the DCM  12  by using the respective authenticators (S 5077 ). Here, it is better to verify not only write data for version upgrade but also write data for rollback. 
     When the verification of the write data is successful, the CGW  13  requests the power supply management ECU  20  to turn on the IG power (S 5078 ). When installation is performed during parking (the IG switch  42  is turned off and the ACC switch  41  is turned off), in a case where the rewrite target ECU  19  is an IG ECU or an ACC ECU, power is required to be supplied to start the rewrite target ECU  19 . The power supply management ECU  20  requests the power supply control circuit  43  to provide the same power as in an ON state of the IG power (S 5079 ). When the power is supplied to the IG power line  39  by the power supply control circuit  43 , the IG ECU and the ACC ECU are started (wake-up). 
     Thereafter, the CGW  13  requests the ECU (ID 5 ), the ECU (ID 5 ), and the ECU (ID 6 ), which are the non-rewrite target ECUs  19 , and the ECU (ID 2 ) and the ECU (ID 3 ), which are subjected to rewriting second and the subsequent order, to sleep (S 5080 ). Here, the second rewrite target ECU  19  is subjected to rewriting after the first rewrite target ECU  19  is subjected to rewriting, but a plurality of rewrite target ECUs  19  may be subjected to rewriting simultaneously and in parallel. In this case, only the non-rewrite target ECU  19  is requested to sleep. 
     The CGW  13  monitors a remaining battery charge (S 5081 ) and monitors communication loads of the buses (S 5082 ) in parallel with installation in each rewrite target ECU  19 . The CGW  13  refers to a value of a battery load and a value of a bus load (bus load table) extracted from the CGW rewrite specification data, and controls installation within a range that does not exceed an allowable value. For example, when the battery load reaches the allowable value in a parking state, the CGW  13  stops the installation at that time. 
     For example, when the bus load of the first bus to which the rewrite target ECU (ID 1 ) is connected reaches the allowable value, the CGW  14  reduces the frequency of transmitting the write data to the ECU (ID 1 ). The monitoring is finished when installation in all of the rewrite target ECUs  19  is completed. In a case of a single-bank memory, since the installation cannot be finished in the middle of the installation, it is necessary to check that there is a sufficient remaining battery charge before initiation of the installation. 
     The CGW  13  notifies the ECU (ID 1 ) subjected to rewriting first to initiate installation (S 5101 ). When the ECU (ID 1 ) is notified of initiation of installation from the CGW  13 , the ECU (ID 1 ) causes a state to transition to a wireless program update mode (S 5102 ). Since the ECU (ID 1 ) is a single-bank memory ECU, the ECU (ID 1 ) cannot execute an application program or perform a diagnosis process using a tool in parallel, and enters a wireless program update only mode. 
     When the CGW  13  performs installation on the ECU (ID 1 ) subjected to rewriting first, the CGW  13  authenticates access by using a security access key (S 5103 ). When authentication of access to the ECU (ID 1 ) is successful, the CGW  13  transmits information of the entire data that is the write data to the ECU (ID 1 ). 
     The ECU (ID 1 ) uses the information of the received entire data to determine whether or not the write data is consistent with the ECU (S 5104 ). In a case where it is determined that the write data is consistent, the ECU (ID 1 ) performs a write process. 
     The CGW  13  acquires a divided file of a predetermined size (for example, 1 k bytes) of the write data that is transmitted from the DCM  12  to the ECU (ID 1 ) and distributes the divided file to the ECU (ID 1 ) (S 5105 ). The ECU (ID 1 ) writes the divided file received from the CGW  13  into the flash memory  33   d  (S 5106 ). When writing is completed, the ECU (ID 1 ) stores a retry point indicating a flash memory address at which the divided file is written such that writing can be resumed from the middle (S 5107 ). As the retry point, a flag indicating a process that has been executed among erasure, writing, and the subsequent processes on the flash memory may be stored. When the retry point is stored, the ECU (ID 1 ) notifies the CGW  13  of write completion (S 5108 ). 
     When the write completion notification is received from the ECU (ID 1 ), the CGW  13  notifies the center device  3  of rewrite status progress information via the DCM  12  (S 5109 ). The progress information includes data such as the installation phase and the write data that has been written in terms of cumulative bytes in the ECU (ID 1 ). The center device  3  updates a web screen that can be connected from the mobile terminal  6  on the basis of the progress information transmitted from the DCM  12  (S 5110 ). The mobile terminal  6  is connected to the center device  3  and displays, for example, a percentage of currently completed installation as the updated progress situation (S 5111 ). Consequently, even in a case where the vehicle is in the parking state and the user is outside the vehicle, the mobile terminal  6  can recognize a progress situation of the installation. Here, the progress may be displayed on the in-vehicle display  7  instead of the mobile terminal  6 . When a rewrite completion notification is received from the ECU (ID 1 ), the CGW  13  notifies the in-vehicle display  7  of rewrite status progress information (S 5112 ). The in-vehicle display  7  updates and displays a progress situation screen (S 5113 ). In a case of a double-bank memory configuration such as the ECU (ID 2 ) and the ECU (ID 3 ), installation is possible even when the vehicle is in a traveling state. Thus, for example, when the vehicle is in an IG switch-on state, the in-vehicle display  7  may display the progress situation. 
     When the write completion notification is received from the ECU (ID 1 ), the CGW  13  acquires a second divided file as the next write data and distributes the divided file to the ECU (ID 1 ). Thereafter, the processes in S 5105  to S 5113  are repeatedly performed up to an N-th divided file as the last write data. When writing up to the N-th divided file is completed, the ECU (ID 1 ) verifies the integrity of the update program of the flash memory and checks whether or not the update program has been written correctly (S 5114 ). When the CGW  13  is notified from the ECU (ID 1 ) that all of the divided files have been written and the integrity verification has been successful, the CGW  13  requests the ECU (ID 1 ) to sleep (S 5115 ). The ECU (ID 1 ) temporarily sleeps without being started by the installed update program. 
     The CGW  13  requests the second rewrite ECU (ID 2 ) to wake up (S 5201 ). The CGW  13  notifies the ECU (ID 2 ) that a program is to be updated wirelessly and installation is initiated (S 5202 ). The ECU (ID 2 ) causes a state to transition to a wireless program update mode as an internal state (S 5203 ). The ECU (ID 2 ) having a double-bank memory can execute an application program and diagnosis using tools during the wireless program update mode. The CGW  13  authenticates access to the ECU (ID 2 ) (S 5204 ). The ECU (ID 2 ) determines whether or not difference data that is the write data is consistent with the ECU (S 5205 ). Since the ECU (ID 2 ) has a double-bank memory, the ECU (ID 2 ) also determines whether or not the write data is consistent with an inactive bank of the flash memory. For example, assuming that the bank-A of the ECU (ID 2 ) is an active bank and the bank-B is an inactive bank, in a case where the write data is an address that is not consistent with the bank-B, the CGW  13  notifies the center device  3  via the DCM  12  that the write data is erroneous without proceeding to the subsequent process. The CGW  13  performs a rollback process described later. In a case where it is determined that the write data is consistent with the ECU, a write process is performed on the ECU (ID 2 ). Thereafter, processes in S 5206  to S 5216  related to the ECU (ID 2 ) are the same as those in S 5105  to S 5115 . In S 5207 , when the difference data is written into the ECU (ID 2 ) having a double-bank memory, as illustrated in  FIG. 18 , a difference is restored by using old data and the difference data to generate new data, and the new data is written into the flash memory  33   d.    
     The CGW  13  requests the third rewrite ECU (ID 3 ) to wake up when the entire installation is completed in the ECU (ID 2 ) and the ECU (ID 2 ) sleeps (S 5301 ). The CGW  13  notifies the ECU (ID 3 ) that the program is to be updated wirelessly and installation is initiated (S 5302 ). The ECU (ID 3 ) causes a state to transition to a wireless program update mode as an internal state (S 5303 ). The CGW  13  authenticates access to the ECU (ID 3 ) (S 5304 ). The ECU (ID 3 ) determines whether or not difference data that is the write data is consistent with the ECU (S 5305 ). In a case where it is determined that the write data is consistent with the ECU, a write process is performed on the ECU (ID 3 ). Thereafter, processes in S 5306  to S 5315  related to the ECU (ID 3 ) are the same as those in S 5105  to S 5114 . 
     When the entire installation in the ECUs (ID 3 ) is completed, the CGW  13  finishes monitoring of the remaining battery charge and monitoring of the communication loads of the buses (S 5316  and S 5317 ). The CGW  13  requests the ECU (ID 1 ) and the ECU (ID 2 ) to wake up (S 5401 ). 
     The CGW  13  requests each ECU to activate the updated program in order to start the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ) simultaneously with the updated programs (S 5402 ). In a case of an ECU that does not cope with an activation request, it is preferable to notify the ECU of power-off and power-on instead of the activation request and thus to cause the ECU to be restarted. 
     When an activation request is received from the CGW  13 , the ECU (ID 1 ) restarts itself (S 5403 ). Since the ECU (ID 1 ) has a single-bank memory, the ECU (ID 1 ) is started by the updated program when being restarted. When restarting after installation is completed, the ECU (ID 1 ) notifies the CGW  13  of an updated program version along with activation completion (S 5404 ). 
     When an activation request is received from the CGW  13 , the ECU (ID 2 ) updates the stored active bank information from the bank-A to the bank-B (S 5405 ), and restarts itself (S 5406 ). When the ECU (ID 2 ) is started normally in the bank-B, the ECU (ID 2 ) notifies the CGW  13  of activation completion along with an updated program version and the active bank information (S 5407 ). 
     When an activation request is received from the CGW  13 , the ECU (ID 3 ) updates the stored active bank information from the bank-A to the bank-B (S 5408 ), and restarts itself (S 5409 ). When the ECU (ID 3 ) is started normally in the bank-B, the ECU (ID 3 ) notifies the CGW  13  of activation completion along with an updated program version and the active bank information (S 5410 ). 
     When the activation completion notifications are received from the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ), the CGW  13  notifies the center device  3  of the program update completion along with the updated program versions and the active bank information related to the rewrite targets ECU (ID 1 ), ECU (ID 2 ), and ECU (ID 3 ) via the DCM  12  (S 5411 ). The center device  3  registers the information of which the notification is sent from the DCM  12  into the database (S 5412 ), and also updates the web screen to display indicating completion as a progress situation (S 5413 ). The mobile terminal  6  is connected to the center device  3 , and displays a web screen indicating that the program update is completed (S 5414 ). When the activation completion notifications are received from the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ), the CGW  13  notifies the in-vehicle display  7  of program update completion as a progress situation (S 5415 ). The in-vehicle display  7  displays information indicating that the program update has been completed (S 5416 ). In a case where progress display is not necessary, such as when the vehicle is in a parking state, the CGW  13  does not notify the in-vehicle display  7  of the progress. 
     Finally, the CGW  13  requests the power supply management ECU  20  to turn off the IG power (S 5418 ). The power supply management ECU  20  requests the power supply control circuit  43  to cut off the supply of power in order to return to a power supply state of IG switch-off before initiation of the installation. When the supply of power to the IG power line  39  and the ACC power line  38  is cut off by the power supply control circuit  43 , the ECU (ID 1 ), the ECU (ID 2 ), the ECU (ID 4 ), the ECU (ID 5 ), and the ECU (ID 6 ) are brought into a stop state. 
     In the above examples, a description has been made of a case where the ECU (ID 1 ) having a single-bank memory is also subjected to program update, and thus when the processes from installation to activation are continuously performed when the vehicle is in a parking state. However, for example, in a case where all the rewrite target ECUs  19  have double-bank memories, installation can be performed on the background while the vehicle is traveling. There may be a configuration in which the mobile terminal  6  obtains an approval for activation from the user at the time at which installation in the rewrite target ECU  19  is completed, 
     Next, a description will be made of a rollback sequence when cancellation of program update is selected by the user during installation of an application program with reference to  FIGS. 230 to 233 . Specifically, a description will be made of a case where installation is completed in the ECU (ID 1 ), and cancellation is selected by the user during installation in the ECU (ID 2 ). 
     When the center device  3  is notified of cancellation of program update from the mobile terminal  6 , the center device  3  instructs the vehicle-side system  4  to cancel the program update (S 6001 ). The center device  3  changes a web screen to a display aspect during rollback as a progress situation (S 6002 ). Mobile terminal  6  displays a web screen indicating the progress situation during rollback (S 6003 ). 
     When the CGW  13  is instructed to cancel the program update from the center device  3  via the DCM  12 , the CGW  13  determines an ECU requiring a rollback process and a necessary rollback process on the basis of memory configurations and installation statuses of the rewrite targets ECU (ID 1 ), ECU (ID 2 ), and ECU (ID 3 ) (S 6004 ). In this example, it is determined that a rollback process of completing installation in the ECU (ID 2 ) and returning the ECU (ID 1 ) to an original version is necessary. 
     The CGW  13  notifies the in-vehicle display  7  of rollback progress (S 6005 ). When the in-vehicle display  7  is notified of the rollback progress from the CGW  13 , the in-vehicle display  7  changes a display aspect to a rollback display aspect, and displays the progress (S 6006 ). The in-vehicle display  7  displays, for example, “during rollback”, and also displays the progress of the ECU (ID 1 ) requiring rollback as 0% and the progress of the ECU (ID 2 ) as 0%. 
     The CGW  13  continues to install the write data as a rollback process for the ECU (ID 2 ). Since the ECU (ID 2 ) has a double-bank memory, the ECU (ID 2 ) can stop the installation in the bank-B that is an inactive bank halfway, and can be continuously operated with the bank-A as an active bank. However, in a case where the write data is installed halfway in the bank-B which is thus in an incomplete state, a difference cannot be restored correctly at the next installation using difference data. Therefore, the installation is continuously performed in the ECU (ID 2 ) to the end. 
     Specifically, the CGW  13  acquires a divided file (for example, 1 k bytes) of the write data that is transmitted to the ECU (ID 2 ) from the DCM  12 , and distributes the divided file to the ECU (ID 2 ) (S 6007 ). The ECU (ID 2 ) writes the divided file received from the CGW  13  into the flash memory  33   d  (S 6008 ). When writing is completed, the ECU (ID 2 ) stores a retry point (S 6009 ) such that writing can be resumed from the middle, and notifies the CGW  13  of write completion (S 6010 ). 
     When the write completion notification is received from the ECU (ID 2 ), the CGW  13  notifies the center device  3  of rollback status progress information via the DCM  12  (S 6011 ). The rollback status progress information is, for example, data such as a data amount required to be written as rollback for the ECU (ID 2 ), and a cumulative amount of written data of the required data amount. The center device  3  updates a web screen that can be connected from the mobile terminal  6  on the basis of the progress information transmitted from the DCM  12  (S 6012 ). The mobile terminal  6  displays, for example, a web screen related to a percentage of currently completed rollback or the like as the updated progress situation (S 6013 ). Here, the progress may be displayed on the in-vehicle display  7  instead of the mobile terminal  6 . When a rewrite completion notification is received from the ECU (ID 2 ), the CGW  13  notifies the in-vehicle display  7  of rollback status progress information (S 6014 ). The in-vehicle display  7  updates and displays a progress situation screen (S 6015 ). Thereafter, the processes in S 6007  to S 6015  are repeatedly performed up to an N-th divided file as the last write data. 
     When the N-th divided file is written, the ECU (ID 2 ) verifies the integrity of the update program of the flash memory  33   d  (S 6016 ). When an installation completion notification is received from the ECU (ID 2 ), the CGW  13  requests the ECU (ID 2 ) to sleep (S 6017 ). The ECU (ID 2 ) sleeps without being started by the update program installed in the bank-B that is an inactive bank. 
     Subsequently, the CGW  13  requests the ECU (ID 1 ) to wake up so as to perform a rollback process on the ECU (ID 1 ) (S 6101 ). The CGW  13  notifies the ECU (ID 1 ) that installation for rollback is to be initiated (S 6102 ). When the ECU (ID 1 ) is notified of the installation initiation from the CGW  13 , the ECU (ID 1 ) causes a state to transition to a wireless program update mode (S 6103 ). The CGW  13  authenticates access to ECU (ID 1 ) (S 6104 ). When access authentication is successful, the ECU (ID 1 ) determines whether or not rollback write data is consistent with the ECU (S 6105 ). In a case where it is determined that the rollback write data is consistent with the ECU, a write process is performed on the ECU (ID 1 ). 
     The CGW  13  acquires a divided file of a predetermined size (for example, 1 k bytes) of the rollback write data that is transmitted from the DCM  12  to the ECU (ID 1 ), and distributes the divided file to the ECU (ID 1 ) (S 6016 ). The ECU (ID 1 ) writes the divided file received from the CGW  13  into the flash memory  33   d  (S 6107 ). When writing is completed, the ECU (ID 1 ) stores a retry point indicating a flash memory address at which the divided file is written such that writing can be resumed from the middle (S 6108 ). When the retry point is stored, the ECU (ID 1 ) notifies the CGW  13  of write completion (S 6109 ). 
     When the write completion notification is received from the ECU (ID 1 ), the CGW  13  notifies the center device  3  of rewrite status progress information via the DCM  12  (S 6110 ). The center device  3  updates a web screen that can be connected from the mobile terminal  6  on the basis of the progress information transmitted from the DCM  12  (S 6111 ). The mobile terminal  6  is connected to the center device  3  and displays, for example, a percentage of currently completed rollback as the updated progress situation (S 6112 ). Here, the progress may be displayed on the in-vehicle display  7  instead of the mobile terminal  6 . When a write completion notification is received from the ECU (ID 1 ), the CGW  13  notifies the in-vehicle display  7  of rewrite status progress information (S 6113 ). The in-vehicle display  7  updates and displays a rollback progress situation screen (S 6114 ). When the write completion notification is received from the ECU (ID 1 ), the CGW  13  acquires a second divided file as the next write data and distributes the divided file to the ECU (ID 1 ). Thereafter, he processes in S 6106  to S 6114  are repeatedly performed up to an N-th divided file as the last write data. 
     When writing up to the N-th divided file is completed, the ECU (ID 1 ) verifies the integrity of the rollback program of the flash memory and checks whether or not the rollback program has been written correctly (S 6115 ). When the CGW  13  is notified from the ECU (ID 1 ) that all of the divided files have been written and the integrity verification has been successful, the CGW  13  finishes monitoring of the remaining battery charge and monitoring of the communication loads of the buses (S 6116  and S 6117 ). 
     Subsequently, the CGW  13  requests the ECU (ID 2 ) and the ECU (ID 3 ) to wake up (S 6201 ). The CGW  13  requests rollback activation tot the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ) to be started in an old version before the installation (S 6202 ). The ECU (ID 1 ) having a single-bank memory starts the old version program through restarting as in rewriting during the normal time. Unlike rewriting during the normal time, the ECU (ID 2 ) and ECU (ID 3 ) having double-bank memories start the programs in the bank-A that is the current active bank without changing the active bank. 
     When the rollback activation request is received from the CGW  13 , the ECU (ID 1 ) restarts itself (S 6203 ). When the restart is completed, the ECU (ID 1 ) notifies the CGW  13  of a program version along with rollback activation completion (S 6204 ). 
     When the rollback activation request is received from the CGW  13 , the ECU (ID 2 ) restarts itself without updating the stored active bank information (S 6205 ). When the ECU (ID 2 ) is started normally in the bank-A that is still an active bank, the ECU (ID 2 ) notifies the CGW  13  of a program version and active bank information along with rollback activation completion (S 6206 ). 
     When the rollback activation request is received from the CGW  13 , the ECU (ID 3 ) restarts itself without updating the stored active bank information (S 6207 ). When the ECU (ID 3 ) is started normally in the bank-A that is still an active bank, the ECU (ID 3 ) notifies the CGW  13  of a program version and active bank information along with rollback activation completion (S 6208 ). 
     When the rollback activation completion notifications are received from the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ), the CGW  13  notifies the center device  3  of the rollback completion via the DCM  12  (S 6209 ). Here, the CGW  13  also sends a notification of the program version and the active bank information related to the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ). The center device  3  registers the information sent from the DCM  12  into the database (S 6210 ) and also updates the web screen to display indicating cancellation completion as a progress situation (S 6211 ). The mobile terminal  6  is connected to the center device  3 , and displays a web screen indicating that cancellation is completed (S 6212 ). 
     When the rollback activation completion notifications are received from the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ), the CGW  13  notifies the in-vehicle display  7  of rollback completion as a progress situation (S 6213 ). The in-vehicle display  7  displays the fact that the rollback is completed (S 6214 ). 
     Finally, the CGW  13  requests the power supply management ECU  20  to turn off the IG power (S 6215 ). The power supply management ECU  20  requests the power supply control circuit  43  to cut off the supply of power in order to return to a state of IG switch-off before initiation of the installation. When the supply of power to the IG power line  39  and the ACC power line  38  is cut off by the power supply control circuit  43 , the ECU (ID 1 ), the ECU (ID 2 ), the ECU (ID 4 ), the ECU (ID 5 ), and the ECU (ID 6 ) are brought into a stop state. 
     As described above, it is possible to perform program update on a plurality of the rewrite target ECUs  19  by using the CGW  13  as a reprogramming master. In the present embodiment, a description has been made of a case where an application program is rewritten with the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ) as one group, but the same applies to a case where the application program is rewritten in the ECU (ID 4 ), the ECU (ID 5 ), and the ECU (ID 6 ) as a second group. In this case, installation and activation are performed on the ECUs  19  of the first group, and then installation and activation are performed on the ECUs  19  of the second group. 
     Application programs in the DCM  12 , the CGW  13 , the in-vehicle display device  7 , the power supply management ECU  20 , alternatively can be rewritten in the same manner. However, since the application programs are required to be able to be operated during program update, these ECUs are configured to have double-bank memories. 
     Next, a configuration of the center device  3  will be described with reference to  FIGS. 234 to 270 . First to fifth embodiments will be described. 
     First Embodiment 
     Hereinafter, the first embodiment will be described with reference to  FIGS. 234 to 253 . A vehicle program rewriting system is a system capable of rewriting an application program such as vehicle control and diagnosis of an ECU mounted on a vehicle through OTA. As illustrated in  FIG. 234 , a vehicle program rewriting system  1  includes a center device  3  on a communication network  2  side, a vehicle-side system  4  on a vehicle side, and a display terminal  5 . The communication network  2  is configured to include, for example, a mobile communication network such as a 4G line, the Internet, and Wireless Fidelity (Wi-Fi (registered trademark)). 
     The display terminal  5  is a terminal having a function of receiving operation input from a user and a function of displaying various screens, and is, for example, a mobile terminal  6  such as a smartphone or a tablet computer that can be carried by a user, and an in-vehicle display  7  such as a display or a meter display that is also used as a navigation function disposed in a vehicle compartment. The mobile terminal  6  can be connected to the communication network  2  as long as the mobile terminal  6  is within a communication range of a mobile communication network. The in-vehicle display  7  is connected to the vehicle-side system  4 . 
     As long as a user is located outside the vehicle compartment and is within the communication range of the mobile communication network, the user can perform operation input while checking various screens related to rewriting of an application program with the mobile terminal  6 , and can perform a procedure related to the rewriting of the application program. In the vehicle compartment, the user can perform operation input while checking various screens related to rewriting of the application program with the in-vehicle display  7 , and can perform a procedure related to rewriting of the application program. That is, the user can use the mobile terminal  6  and the in-vehicle display  7  separately outside the vehicle compartment and in the vehicle compartment, and can perform a procedure related to rewriting of the application program. 
     The center device  3  controls an OTA function of the communication network  2  side in the vehicle program rewriting system  1 , and functions as an OTA center. The center device  3  includes a file server  8 , a web server  9 , and a management server  10 , and each of the servers  8  to  10  is configured to be able to perform data communication with each other. 
     The file server  8  has a function of managing an application program transmitted from the center device  3  to the vehicle-side system  4 , and is a server that manages an ECU program provided from a supplier or the like that is a provider of the application program, information associated with the ECU program, distribution specification data provided from an original equipment manufacturer (OEM), vehicle conditions acquired from the vehicle-side system  4 , and the like. The file server  8  can perform data communication with the vehicle-side system  4  via the communication network  2 , and transmits a distribution package in which the reprogramming data and the distribution specification data are packaged to the vehicle-side system  4  when a download request for the distribution package is generated. The web server  9  is a server that manages web information, and provides various screens related to rewriting an application program to the mobile terminal  6 . The management server  10  manages personal information of a user registered in a service of rewriting an application program, a rewrite history of an application program for each vehicle, and the like. 
     The vehicle-side system  4  has a master device  11 . The master device  11  has a DCM  12  and a CGW  13 , and the DCM  12  and the CGW  13  are connected to each other via a first bus  14  to be able to perform data communication. The DCM  12  is an in-vehicle communication device that performs data communication with the center device  3  via the communication network  2 , and, when a distribution package is downloaded from the file server  8 , extracts write data from the distribution package, and transfers the write data to the CGW  13 . 
     The CGW  13  is a vehicle gateway device having a data relay function, and, when the write data is acquired from the DCM  12 , distributes the write data to a rewrite target ECU in which an application program is rewritten. The master device  11  controls the OTA function of the vehicle side in the vehicle program rewriting system  1 , and functions as an OTA master. In  FIG. 234 , although the DCM  12  and the in-vehicle display  7  are configured to be connected to the same first bus  14  as an example, the DCM  12  and the in-vehicle display  7  may be configured to be connected to separate buses. 
     In addition to the first bus  14 , a second bus  15 , a third bus  16 , a fourth bus  17 , and a fifth bus  18  are connected to the CGW  13  as buses inside the vehicle, and various ECUs  19  are connected via the buses  15  to  17 , and a power supply management ECU  20  is connected via the bus  18 . 
     The second bus  15  is, for example, a body system network bus. The ECUs  19  connected to the second bus  15  are ECUs controlling the body system including, for example, a door ECU controlling locking/unlocking of a door, a meter ECU controlling display on the meter display, an air conditioner ECU controlling driving of an air conditioner, and a window ECU controlling opening and closing of a window. The third bus  16  is, for example, a traveling system network bus. The ECUs  19  connected to the third bus  16  are ECUs controlling the traveling system including, for example, an engine ECU controlling driving of an engine, a brake ECU controlling driving of a brake, an ECT (Electronic Toll Collection System (ETC) (registered trademark)) ECU controlling driving of an automatic transmission, and a power steering ECU controlling a driving of a power steering. 
     The fourth bus  17  is, for example, a multimedia system network bus. The ECUs  19  connected to the fourth bus  17  are ECUs controlling the multimedia system including, for example, a navigation ECU controlling a navigation system, and an ETC ECU controlling an electronic toll collection system, that is, an ECT system. The buses  15  to  17  may be system buses other than the body system network bus, the traveling system network bus, and the multimedia system network bus. The number of buses and the number of the ECUs  19  are not limited to the exemplified configuration. 
     The power supply management ECU  20  is an ECU having a function of managing power to be supplied to the DCM  12 , the CGW  13 , the various ECUs  19 , and the like. 
     A sixth bus  21  is connected to the CGW  13  as a bus outside the vehicle. A data link coupler (DLC) connector  22  to which a tool  23  is detachably connected is connected to the sixth bus  21 . The buses  14  to  18  inside the vehicle and the bus  21  outside the vehicle are configured with, for example, Controller Area Network (CAN) (registered trademark) buses, and the CGW  13  performs data communication with the DCM  12 , the various ECUs  19 , and the tool  23  in accordance with the CAN data communication standard and the diagnosis communication standard (UDS: ISO14229). The DCM  12  and the CGW  13  may be connected to each other via Ethernet, and the DLC connector  22  and the CGW  13  may be connected to each other via Ethernet. 
     When write data is received from the CGW  13 , the rewrite target ECU  19  writes the write data into a flash memory to rewrite an application program. In the above configuration, when a request for acquiring write data is received from the rewrite target ECU  19 , the CGW  13  functions as a reprogramming master that distributes the write data to the rewrite target ECU  19 . When the write data is received from the CGW  13 , the rewrite target ECU  19  functions as a reprogramming slave that writes the write data into the flash memory to rewrite the application program. 
     As an aspect of rewriting the application program, there are a wired rewrite aspect and a wireless rewrite aspect. In the aspect in which the application program is rewritten in a wired manner, when the tool  23  is connected to the DLC connector  22 , the tool  23  transfers the write data to the CGW  13 . The CGW  13  relays or distributes the write data transferred from the tool  23  to the rewrite target ECU  19 . In the aspect of rewriting the application program in a wireless manner, as described above, when the distribution package is downloaded from the file server  8 , the DCM  12  extracts the write data from the distribution package, and transfers the write data to the CGW  13 . 
     As illustrated in  FIG. 235 , the CGW  13  includes a microcomputer  24 , a data transfer circuit  25 , a power supply circuit  26 , and a power detection circuit  27  as electrical functional blocks. The microcomputer  24  includes a central processing unit (CPU)  24   a , a read only memory (ROM)  24   b , a random access memory (RAM)  24   c , and a flash memory  24   d . The microcomputer  24  performs various processes by executing various control programs stored in a non-transitory tangible storage medium, and controls an operation of the CGW  13 . 
     The data transfer circuit  25  controls data communication with the buses  14  to  18  and  21  in accordance with the CAN data communication standard and the diagnosis communication standard. The power supply circuit  26  receives battery power (hereinafter, referred to as +B power), accessory power (hereinafter, referred to as ACC power), and ignition power (hereinafter, referred to as IG power). The power detection circuit  27  detects a voltage value of the +B power, a voltage value of the ACC power, and a voltage value of the IG power received by the power supply circuit  26 , compares the detected voltage values with predetermined voltage threshold values, and outputs comparison results to the microcomputer  24 . The microcomputer  24  determines whether the +B power, the ACC power, and the IG power supplied to the CGW  13  from the outside are normal or abnormal on the basis of the comparison results that are input from the power detection circuit  27 . 
     As illustrated in  FIG. 236 , the ECU  19  includes a microcomputer  28 , a data transfer circuit  29 , a power supply circuit  30 , and a power detection circuit  31  as electrical functional blocks. The microcomputer  28  includes a CPU  28   a , a ROM  28   b , a RAM  28   c , and a flash memory  28   d . The microcomputer  28  performs various processes by executing various control programs stored in a non-transitory tangible storage medium, and controls an operation of the ECU  19 . 
     The data transfer circuit  29  controls data communication with the buses  15  to  17  in accordance with the CAN data communication standard. The power supply circuit  30  receives +B power, ACC power, and IG power. The power detection circuit  31  detects a voltage value of the +B power, a voltage value of the ACC power, and a voltage value of the IG power received by the power supply circuit  30 , compares the detected voltage values with predetermined voltage threshold values, and outputs comparison results to the microcomputer  28 . The microcomputer  28  determines whether the +B power, the ACC power, and the IG power supplied to the ECU  19  from the outside are normal or abnormal on the basis of the comparison results that are input from the power detection circuit  27 . The ECUs  19  fundamentally have the same configuration except that loads such as sensors or actuators connected thereto are different from each other. A fundamental configuration of each of the DCM  12 , the in-vehicle display  7 , and the power supply management ECUs is the same as that of the ECU  19  illustrated in  FIG. 236 . 
     As illustrated in  FIG. 237 , the power supply management ECU  20 , the CGW  13 , and the ECU  19  are connected to a +B power line  32 , an ACC power line  33 , and an IG power line  34 . The +B power line  32  is connected to a positive electrode of a vehicle battery  35 . The ACC power line  33  is connected to the positive electrode of the vehicle battery  35  via an ACC switch  36 . When the user performs an ACC operation, the ACC switch  36  switches from an OFF state to an ON state, and an output voltage of the vehicle battery  35  is applied to the ACC power line  33 . For example, in a case of a vehicle of the type to insert a key into an insertion port, the ACC operation is an operation of rotating the key from an “OFF” position to an “ACC” position by inserting the key into the insertion port, and, in a case of a vehicle of the type to press a start button, the ACC operation is an operation of pressing the start button once. 
     The IG power line  34  is connected to the positive electrode of the vehicle battery  35  via an IG switch  37 . When the user performs an IG operation, the IG switch  37  switches from an OFF state to an ON state, and an output voltage of the vehicle battery  35  is applied to the IG power line  34 . For example, in a case of a vehicle of the type to insert a key into an insertion port, the IG operation is an operation of rotating the key from an “OFF” position to an “ON” position by inserting the key into the insertion port, and, in a case of a vehicle of the type to press a start button, the IG operation is an operation of pressing the start button twice. A negative electrode of the vehicle battery  35  is grounded. 
     When both of the ACC switch  36  and the IG switch  37  are in an OFF state, only the +B power is supplied to the vehicle-side system  4 . The state in which only the +B power is supplied to the vehicle-side system  4  will be referred to as a +B power supply state. When the ACC switch  36  is in an ON state and the IG switch  37  is in an OFF state, the ACC power and the +B power are supplied to the vehicle-side system  4 . The state in which the ACC power and the +B power are supplied to the vehicle-side system  4  will be referred to as an ACC power supply state. When of both the ACC switch  36  and the IG switch  37  are in an ON state, the +B power, the ACC power, and the IG power are supplied to the vehicle-side system  4 . The state in which the +B power, the ACC power, and the IG power are supplied to the vehicle-side system  4  will be referred to as an IG power supply state. 
     The ECUs  19  have different start conditions depending on power supply states, and are classified as a +B ECU that is started in the +B power supply state, an ACC ECU that is started in the ACC power supply state, and an IG ECU that is started in the IG power supply state. For example, the ECU  19  driven in an application such as vehicle theft is the +B ECU. For example, the ECU  19  driven in a non-traveling system application such as an audio is the ACC ECUs. For example, the ECU  19  driven in a traveling system application such as engine control is the IG ECU. 
     The CGW  13  transmits a start request to the ECU  19  that is in a sleep state, and thus causes the ECU  19  that is a transmission destination of the start request to transition from the sleep state to an active state. The CGW  13  also transmits a sleep request to the ECU  19  that is in an active, and thus causes the ECU  19  that is a transmission destination of the sleep request to transition from the active state to a sleep state. The CGW  13  selects the ECU  19  that is a transmission destination of the start request or the sleep request from among the plurality of ECUs, for example, by making waveforms of the transmission signals to be transmitted to the buses  15  to  17  different from each other. 
     The power supply control circuit  38  is connected in parallel to the ACC switch  36  and the IG switch  37 . The CGW  13  transmits a power supply control request to the power supply management ECU  20  and causes the power supply management ECU  20  to control the power supply control circuit  38 . That is, the CGW  13  transmits a power supply start request as the power supply control request to the power supply management ECU  20 , to connect the ACC power line  33  or the IG power line  34  to the positive electrode of the vehicle battery  35  in the power supply control circuit  38 . In this state, the ACC power or IG power is supplied to the vehicle-side system  4  even when the ACC switch  36  and the IG switch  37  is turned off. The CGW  13  transmits a power supply stop request as the power supply control request to the power supply management ECU  20 , to disconnect the ACC power line  33  or IG power line  34  from the positive electrode of the vehicle battery  35  in the power supply control circuit  38 . 
     The DCM  12 , the CGW  13 , and the ECU  19  have a self-retention power function. That is, when vehicle power switches from the ACC power or the IG power to the +B power in the active state, the DCM  12 , the CGW  13 , and the ECU  19  do not transition from the active state to the stop state or the sleep state immediately after the switching, but continue the active state for a predetermined time even immediately after the switching, and thus self-retain drive power. The DCM  12 , the CGW  13 , and the ECU  19  transition from the active state to the stop state or the sleep state when a predetermined time (for example, several seconds) has elapsed immediately after the vehicle power switches from the ACC power or IG power to the +B power. 
     Next, a distribution package distributed from the center device  3  to the master device  11  will be described with reference to  FIGS. 238 and 239 . In the vehicle program rewriting system  1 , reprogramming data including write data provided from a supplier as a provider of an application program and rewrite specification data provided from an OEM is generated. The write data provided from the supplier includes difference data corresponding to a difference between an old application program and a new application program, and the entire data corresponding to the whole of the new application program. The difference data or the entire data may be compressed by using a well-known data compression technique.  FIG. 238  exemplifies a case where difference data is provided as write data from suppliers A to C, and reprogramming data is generated from encrypted difference data and an authenticator of the ECU (ID 1 ) provided from the supplier A, encrypted difference data and an authenticator of the ECU (ID 2 ) provided from the supplier B, and encrypted difference data and an authenticator of the ECU (ID 3 ) provided from the supplier C, and rewrite specification data provided from the OEM. The authenticator is added to each piece of write data. 
     Although  FIG. 238  illustrates the difference data used to update the old application program to the new application program, rollback difference data used to roll back the new application program to the old application program may also be included in the reprogramming data. For example, in a case where the rewrite target ECU  19  has a single-bank memory, the rollback difference data is included in the reprogramming data. 
     The rewrite specification data provided from the OEM includes, as information related to rewriting of the application program, information for specifying the rewrite target ECU  19 , information for specifying a rewrite order when there are a plurality of rewrite target ECUs  19 , information for specifying a rollback method described later, and the like, and is data defining an operation related to rewriting in the DCM  12 , the CGW  13 , or rewrite target ECU  19 . The rewrite specification data is classified into DCM rewrite specification data used by the DCM  12  and CGW rewrite specification data used by the CGW  13 . Information required to read files corresponding to the rewrite target ECU  19  is described in the DCM rewrite specification data. As described above, information required to control rewriting in the rewrite target ECU  19  is described in the CGW rewrite specification data. 
     When the DCM rewrite specification data is acquired, the DCM  12  analyzes the DCM rewrite specification data, and controls operations related to rewriting such as transferring write data to the CGW  13  according to the analysis result. When the CGW rewrite specification data is acquired, the CGW  13  analyzes the CGW rewrite specification data, and controls operations related to rewriting such as acquiring write data from the DCM  12  and distributing the write data to the rewrite target ECU  19  according to the analysis result. 
     In the file server  8 , the above-described reprogramming data is registered, and the distribution specification data provided from the OEM is registered. The distribution specification data provided from the OEM is data defining an operation related to display of various screens in the display terminal  5 . 
     When the reprogramming data and the distribution specification data are registered, the file server  8  encrypts the registered reprogramming data, and generates a distribution package in which a package authenticator for authenticating the package, the encrypted reprogramming data, and the distribution specification data are packaged into a single file. When a download request for the distribution package is received from the outside, the file server  8  transmits the distribution package to the DCM  12 . In  FIG. 238 , a case is exemplified in which the file server  8  generates the distribution package storing the reprogramming data and the distribution specification data and transmits the reprogramming data and the distribution specification data to the DCM  12  together, but the reprogramming data and the distribution specification data may be separately transmitted to the DCM  12 . That is, the file server  8  may transmit the distribution specification data to the DCM  12  first, and may transmit the reprogramming data to the DCM  12  later. The file server  8  may transmit the distribution package and the package authenticator to the DCM  12  by generating the reprogramming data and the distribution specification data as a distribution package that is a single file. 
     When the distribution package is downloaded from the file server  8 , the DCM  12  verifies the package authenticator stored in the distribution package and the encrypted reprogramming data, and decrypts the encrypted reprogramming data when the verification result is positive. When the encrypted reprogramming data is decrypted, the DCM  12  unpackages the decrypted reprogramming data, and generates encrypted difference data, an authenticator, DCM rewrite specification data, and CGW rewrite specification data for each of the ECUs.  FIG. 239  illustrates a case where the encrypted difference data and the authenticator of the ECU (ID 1 ), the encrypted difference data and the authenticator of the ECU (ID 2 ), the encrypted difference data and the authenticator of the ECU (ID 3 ), and the rewrite specification data are generated. 
       FIG. 240  is a block diagram mainly illustrating portions related to functions of the servers  8  to  10  in the center device  3 .  FIG. 241  illustrates an outline of processes performed by the center device  3  with respect to program update in the ECU. In the following description, a “database” will be referred to as a “DB” in some cases. As illustrated in  FIG. 240 , the center device  3  includes a package management unit  3 A, a configuration information management unit  3 B, an individual vehicle information management unit  3 C, and a campaign management unit  3 D. The package management unit  3 A includes a specification data generation unit  201 , a package generation unit  202 , a package distribution unit  203 , an ECU reprogramming data DB  204 , an ECU metadata DB  205 , and a package DB  206 . The configuration information management unit  3 B includes a configuration information registration unit  207  and a configuration information DB  208 . 
     The supplier registers ECU individual data by using an input unit  218  and a display unit  219  that are user interface (UI) functions of the management server  10 . The ECU individual data includes a program file such as a new program or difference data, verification data or a size of the program file, program file related information such as encryption methods, and ECU attribute information such as a memory configuration of the ECU  19 . The program file is stored in the ECU reprogramming data DB  204 . The ECU attribute information is stored in the ECU metadata DB  205 . The program file related information may be stored in the ECU reprogramming data DB  204  or may be stored in the ECU metadata DB  205 . The ECU reprogramming data DB  204  is an example of an update data storage unit. The ECU metadata DB  205  is an example of a device related information storage unit. 
     The OEM registers approved configuration information in the configuration information DB  208  for each vehicle type via the configuration information registration unit  207 . The approved configuration information is configuration information of a vehicle approved by a public organization. The configuration information is identification information regarding hardware and software of the ECU  19  mounted on a vehicle, and is an example of vehicle related information. The configuration information includes identification information of a system configuration formed of a plurality of ECUs  19  and identification information of a vehicle configuration formed of a plurality of systems. As the configuration information, vehicle restriction information related to program update may be registered. For example, group information of the ECU described in the rewrite specification data, a bus load table, and information regarding a battery load may be registered. The ECU metadata DB  205  is an example of a device related information storage unit. The configuration information DB  208  is an example of a vehicle information storage unit. 
     The specification data generation unit  201  refers to each DB and generates rewrite specification data. The package generation unit  202  generates a distribution package including rewrite specification data and reprogramming data, and registers the distribution package in the package DB  206 . The package generation unit  202  may generate a distribution package including the distribution specification data. The package distribution unit  203  distributes the registered distribution package to the vehicle-side system  4 . The distribution package corresponds to a file. 
     The individual vehicle information management unit  3 C includes an individual vehicle information registration unit  209 , a configuration information check unit  210 , an update availability check unit  211 , an SMS transmission control unit  212 , and an individual vehicle information DB  213 . The individual vehicle information registration unit  209  registers individual vehicle information uploaded from individual vehicles in the individual vehicle information DB  213 . The individual vehicle information registration unit  209  may register, as initial values, individual vehicle information at the time of vehicle production or sales in the individual vehicle information DB  213 . When the uploaded individual vehicle information is registered, the configuration information check unit  210  collates the individual vehicle information with the configuration information of the same type vehicle registered in the configuration information DB  208 . The update availability check unit  211  checks the availability of update using a new program, that is, the availability of a campaign with respect to the individual vehicle information. In a case where the individual vehicle information is updated, the SMS transmission control unit  212  transmits a message related to the update to a corresponding vehicle by a short message service (SMS). 
     The campaign management unit  3 D includes a campaign generation unit  214 , a campaign distribution unit  215 , an instruction notification unit  216 , and a campaign DB  217 . The OEM causes the campaign generation unit  214  to generate campaign information that is information related to the program update, and registers the campaign information in the campaign DB  217 . The campaign information here corresponds to the “distribution specification data” described above, and is mainly information regarding an update content displayed on the vehicle-side system  4 . The campaign distribution unit  215  distributes the campaign information to the vehicle. The instruction notification unit  216  notifies the vehicle of a necessary instruction related to the program update. In the vehicle-side system  4 , for example, the user determines whether or not to download the update program on the basis of the campaign information transmitted from the center device  3 , and downloads the update program if necessary. The portions of each of the management units  3 A to  3 D except the databases are functions realized by computer hardware and software. The vehicle communication unit  222  is a functional block for performing data communication between the center device  3  and the vehicle-side system  4  in a wireless manner. 
     Hereinafter, the above process will be described in more detail, and, first, a content of data registered in each database will be described. As illustrated in  FIG. 242 , as an example, the following data is registered in the configuration information DB  208 . A “vehicle type” indicates the type of a vehicle. A “Vehicle SW ID” is a software ID for the entire vehicle, and corresponds to a vehicle software ID. Only one “Vehicle SW ID” is granted to each vehicle, and is updated as versions of application programs of any one or more of the ECUs are updated. A “Sys ID” is an ID of a system when a group of a plurality of ECUs  19  mounted on each vehicle is referred to as a “system”. 
     For example, in  FIG. 234 , a group of body system ECUs  19  is a body system, and a group of traveling system ECUs  19  is a traveling system. The “Sys ID” is updated as versions of application programs of any one or more ECUs forming a system are updated. An “ECU ID” is an ID for identifying a device, indicating the type of ECU. An “ECU SW ID” is a software ID for each ECU and corresponds to an ECU software ID. For the sake of convenience, the “ECU ID” is illustrated to be added with a version of software. The “ECU SW ID” is updated as a version of an application program of a corresponding ECU is updated. Even if the same program version is used in the same “ECU ID”, different “ECU SW IDs” are used when hardware configurations are different from each other. That is, the “ECU SW ID” is also information indicating a product number of the ECU. 
       FIG. 242  illustrates configuration information regarding a vehicle of “vehicle type”=“aaa”. Among the ECUs  19  mounted on a vehicle, an autonomous driving ECU (ADS), an engine ECU (ENG), a brake ECU (BRK), and an electric power steering ECU (EPS) are exemplified. For example, “ECU SW IDs” of “Vehicle SW ID”=“0001” are “ads_001”, “eng_010”, “brk_001”, and “eps_010”, whereas “ECU SW IDs” of “Vehicle SW ID”=“0002” is “ads_002”, “eng_010”, “brk_005”, and “eps_011”, and three software versions are updated. As a result, “Sys ID”=“SA01” is updated to “SA02”, and “Sys ID”=“SA02” is updated to “SA03”. As mentioned above, the initial value is registered in the configuration information DB  208  at the time of production or sales of the vehicle, and is then is updated as versions of application programs of any one or more ECUs is updated. That is, the configuration information DB  208  indicates approved configuration information that is present in the market for each vehicle type. 
     As illustrated in  FIG. 243 , as an example, the following programs and data are registered in the ECU reprogramming data DB  204 . In  FIG. 243 , among the ECUs  19  to be mounted on a certain vehicle type, as ECUs  19  in which application programs are updated, an autonomous driving ECU (ADS), a brake ECU (BRK), and an electric power steering ECU (EPS) are exemplified. With respect to the latest “ECU SW ID” of the update target ECU  19 , old program and new program files of the ECU, the integrity verification data of the new program, an update data file that is difference data between the new program and the old program, integrity verification data of the update data, a rollback data file that is the difference data, and integrity verification data of the rollback data are registered. The integrity verification data is a hash value obtained by applying a hash function to a data value. When the entire data of the new program is used as the update data instead of the difference data, the integrity verification data of the update data is same as the entire data of the new program. 
     Although a data structure of the latest “ECU SW ID” is illustrated in  FIG. 243 , in a case where data of the old “ECU SW ID” is stored, a new program file with the previous “ECU SW ID” may be referred to with respect to the old program file. Each piece of the integrity verification data may have a format in which a value calculated by the supplier is registered, or may have a format in which a value calculated by the center device  3  is registered. 
     As illustrated in  FIG. 244 , the following ECU individual specification data is registered in the ECU metadata DB  205 . For the latest “ECU SW ID”, a size of an update data file, a size of a rollback data file, bank information indicating a bank related to a program among a bank-A, a bank-B, a bank-C, and the like in a case where the flash memory  28   d  included in the ECU  19  has two or more banks, a transfer size, a read address of a program file, and the like are registered. These are examples of update data related information. 
     Attribute information indicating an attribute of the ECU  19  is also registered in the ECU metadata DB  205 . The attribute information is information indicating a hardware attribute and a software attribute regarding the ECU. The “transfer size” is a transfer size when rewrite data is divided and transferred from the CGW  13  to the ECU  19 , and the “key” is a key used when the CGW  13  securely accesses the ECU  19 . These are examples of software attribute information. The “vehicle type” and “ECU ID” also include a memory configuration of the flash memory  28   d  of the ECU  19 , the type of bus to which the ECU  19  is connected, the type of power supply connected to the ECU  19 , and the like. These are examples of hardware attribute information. 
     Here, as the memory configuration, a “single-bank” is a single-bank memory having a single flash bank, a “double-bank” is a double-bank memory having double flash banks, and “suspend” is a single-bank suspend memory having a pseudo-double flash banks. The hardware attribute information and the software attribute information are information used for rewrite control of each ECU  19  in the vehicle-side system  4 . Although the hardware attribute information may be stored in advance in the CGW  13 , in the present embodiment, the hardware attribute information is managed by the center device  3  in order to reduce the management load on the vehicle-side system  4 . The software attribute information is data that directly designates a rewrite operation of each ECU  19 . The software attribute information is managed by the center device  3  such that flexible control in the vehicle-side system  4  can be realized. 
     As illustrated in  FIG. 245 , the following data for each individual vehicle is registered in the individual vehicle information DB  213 . Generally, configuration information for each individual vehicle or status information of an individual vehicle with respect to program update is registered. Specifically, for “VIN” that is an ID of each vehicle, the “Vehicle SW ID”, the “Sys ID”, the “ECU ID”, the “ECU SW ID” and the like that are configuration information are registered. A “Digest” value that is a hash value for the configuration information is also calculated and stored in the center device  3 . An “active bank” is a bank where a program currently operated by the ECU  19  is written in a case where a memory configuration is a double-bank, and an uploaded value is registered along with the configuration information. 
     An “access log” is the date and time when the vehicle uploaded the individual vehicle information to the center device  3 . A “reprogramming status” indicates a status of reprogramming in the vehicle, and includes, for example, “campaign issued”, “activation completed”, and “download completed”. That is, it can be seen from this progress status to which phase the reprogramming in the vehicle advances and in which phase the reprogramming is delayed. When the configuration information or the like is uploaded from the vehicle-side system  4  to the center device  3 , the “VIN” of each vehicle is added to the information or the like. 
     As illustrated in  FIG. 246 , an ID of a distribution package, a distribution package file, and data for verifying the integrity of the distribution package, are registered in the package DB  206 . As illustrated in  FIG. 247 , the following data is registered in the campaign DB  217 . The data is an ID of campaign information, a distribution package ID, message information such as text statements indicating a specific update content as a campaign content, a list of “VINs” which are IDs of campaign target vehicles, a list of “Vehicle SW IDs” before and after the update, a list of “ECU SW IDs” before and after the update, and the like. A “target VIN” list may be registered by collating the individual vehicle information DB  213  with the campaign DB  217 . The campaign information may also be registered in the package DB  206 . 
     Next, an operation of the present embodiment will be described. In  FIG. 248 , a description will be made of a process of registering data in the ECU reprogramming data DB  204  of the package management unit  3 A. As illustrated in  FIG. 248 , the display unit  219  and the input unit  218  start a screen of registering the reprogramming data of the management server  10 , and receive input of new and old program files of the ECU  19  from an operator of the supplier (A 1 ). For example, a UI or the like may be used to register a file in which configuration information is written in a CSV format or the like as a file. Subsequently, the package management unit  3 A generates integrity verification data of the new program (A 2 ), and generates a difference data file as update difference data for update to the new program on the basis of the old program, and integrity verification data of the update difference data (A 3  and A 4 ). 
     Next, a difference data file as rollback difference data for update to the old program on the basis of the new program and integrity verification data of the data are generated (A 5  and A 6 ). The program files and the verification data are registered in the ECU reprogramming data DB  204 , and a new “ECU SW ID” is generated and registered on the basis of the previous “ECU SW ID” (A 7 ). Here, when the entire data is distributed instead of the difference, the step related to the difference data may be omitted. 
     The integrity verification data is a hash value generated, for example, by applying a hash function. For example, in a case where Secure Hash Algorithm 256-bit (SHA-256) is used as the hash function, data values are separated into message blocks every 64 bytes. Then, when data values of the first message block are applied to an initial hash value and thus a hash value with 32-byte length is obtained, a hash value with 32-byte length is sequentially and repeatedly obtained by applying data values of the next message block to the hash value. 
     In  FIG. 249 , a description will be made of a rewrite specification data generation process in the specification data generation unit  201 . Here, the rewrite specification data generation process of for the vehicle of “vehicle type”=“aaa” will be described, but the same applies to other vehicles. 
     The center device  3  starts a specification data generation program of the specification data generation unit  201 , and receives input from an operator of the OEM via the display unit  219  and the input unit  218 . First, the specification data generation unit  201  determines the update target ECU  19 . As illustrated in  FIG. 249 , the specification data generation unit  201  accesses the ECU reprogramming data DB  204  and outputs a display screen on which an update target can be selected from among the registered “ECU SW IDs” to the display unit  219 . The specification data generation unit  201  stores one or more “ECU SW IDs” selected by the operator of the OEM via the input unit  218  in a specific ECU order (B 1 ). Here, the ECU order indicates a rewrite order of the ECUs  19  in the vehicle-side system  4 . The specification data generation unit  201  sets the order designated by the operator of the OEM as the specific ECU order. 
     The specification data generation unit  201  may access the configuration information DB  208  to determine the update target ECU  19  without receiving input from the operator of the OEM. The specification data generation unit  201  refers to an “ECU SW ID” for the latest “Vehicle SW ID” and an “ECU SW ID” for the previous “Vehicle SW ID”, and extracts the ECU  19  subjected to update. For example, in  FIG. 242 , the “ADS”, the “BRK”, and the “EPS” are the update target ECUs  19 . The specification data generation unit  201  sets the order of the ECUs registered in the configuration information DB  208  as the specific ECU order. 
     The specification data generation unit  201  generates group information for ECUs having a plurality of update target “ECU SW IDs” (B 2 ). Here, with reference to the configuration information DB  208 , by using the “Sys ID”, for example, a group 1 includes “ECU IDs” in which the “Sys ID” is “SA01_02”, and a group 2 includes “ECU IDs” in which the “Sys ID” is “SA02_02”. For example, in  FIG. 242 , the group 1 is set to the “ADS”, the group 2 is set to the “BRK” first, and the group 2 is set to the “EPS” second. As described above, the specification data generation unit  201  determines an update target ECU, a group to which the ECU belongs, and an ECU order in the group. 
     Next, the specification data generation unit  201  accesses the ECU metadata DB  205 , and acquires the update data related information, the hardware attribute information, and the software attribute information as the specification data regarding the update target ECU  19  (B 3 ). For example, as illustrated in  FIG. 250 , the update data related information includes an “update program version”, an “update program acquisition address”, an “update program size”, a “rollback program version”, a “rollback program acquisition address”, a “rollback program size”, a “write data type”, and a “write bank”. The hardware attribute information includes a “connection bus”, a “connection power supply”, and a “memory type”. The software attribute information includes “rewrite bank information”, “security access key information”, a “rewrite method”, and a “transfer size”. The “rewrite method” is data indicating whether rewriting is performed by enabling the self-retention power circuit when switching occurs from IG-on to IG-off (self-retention power), or the rewriting is performed according to IG-on and IG-off (power supply control). Information other than a key may be included as the “security access key information”. 
     Hereinafter, each piece of information will be described. 
     The “Write data type” is a type indicating whether a program is difference data or the entire data. The write data type for an update program and the write data type for a rollback program may be described separately. 
     The “write bank” is information indicating a bank in which a program is written for the double-bank memory ECU  19 . 
     The “connection bus” is information for identifying a bus to which the ECU  19  is connected. 
     The “connection power supply” is information indicating a state of a power supply to which the ECU  19  is connected, in which a value indicating any of the battery power (+B power), the accessory power (ACC power), and the ignition power (IG power) is described. 
     The “memory type” is information for identifying a memory configuration of the ECU  19 , in which values indicating a double-bank memory, a single-bank suspend memory (pseudo-double-bank memory), a single-bank memory, and the like are described. 
     The “rewrite bank information” is information indicating which bank of the ECU  19  is a start bank (active bank) and which bank is a rewrite bank (inactive bank). 
     The “security access key information” is information for authenticating access to the ECU  19  by using a key, and includes information such as a key derivation key, a key pattern, and a decryption operation pattern. 
     The “transfer size” is a data size when a program is divided and transferred to the ECU  19 . 
     For example, as illustrated in  FIG. 250 , the “ECU ID” is used as a key to store these pieces of information in the specific ECU order described above. When information regarding all the ECUs is acquired (B 4 ; YES), the specification data generation unit  201  designates “rewrite environment information” for an update target vehicle (B 5 ). The “rewrite environment information” is information used for rewrite control in the vehicle-side system  4  for the group of ECUs or the entire vehicle, and is data directly designating a rewrite operation. For example, the rewrite environment information for the entire vehicle includes a “vehicle condition” indicating whether program update in the vehicle-side system  4  is performed while the vehicle is traveling (while the IG switch is turned on) or while the vehicle is parked (while the IG switch is turned off), a “battery load (a remaining battery charge)” indicating a restriction on the remaining battery charge capable of executing the program update in the vehicle-side system  4 , bus load table information indicating a restriction on a bus load capable of transferring write data in the vehicle-side system  4 , and the like. 
     The rewrite environment information for the group includes the ECUs  19  belonging to the group, the order of ECUs in the group, and the like. In the vehicle-side system  4 , program update is controlled to be synchronized in the group unit, and writing into the ECU  19  is executed in the designated ECU order. The specification data generation unit  201  starts a screen for registering rewrite environment information, and receives input from the operator of the OEM. Alternatively, Excel (registered trademark) in which rewrite environment information is input may be imported. Alternatively, the restriction information registered in the configuration information DB  208  may be extracted. The specification data generation unit  201  uses the generation result in the above step B 2  as the rewrite environment information for the group. 
     The bus load table is a table illustrating a correspondence relationship between a power supply state and an allowable transmission amount for a bus. As illustrated in  FIG. 251 , the allowable transmission amount is a sum of a transmission amount of vehicle control data and write data that can be transmitted with respect to the maximum allowable transmission amount. In this example, since an allowable transmission amount is “80%” with respect to the maximum allowable transmission amount for the first bus, in the IG power supply state, the CGW  13  allows “50%” with respect to the maximum allowable transmission amount as an allowable transmission amount of vehicle control data and “30%” with respect to the maximum allowable transmission amount as an allowable transmission amount of write data. In the ACC power supply state, the CGW  13  allows “30%” with respect to the maximum allowable transmission amount as an allowable transmission amount of the vehicle control data and “50%” with respect to the maximum allowable transmission amount as an allowable transmission amount of the write data. In the +B power supply state, the CGW  13  allows “20%” with respect to the maximum allowable transmission amount as an allowable transmission amount of the vehicle control data, and allows “60%” with respect to the maximum allowable transmission amount as an allowable transmission amount of the write data. The same applies to the second bus and the third bus. 
     Finally, the specification data generation unit  201  locates each piece of the generated or acquired data in accordance with a predetermined data structure, and thus generates rewrite specification data as illustrated in  FIG. 250  (B 6 ). That is, the specification data generation unit  201  generates the rewrite specification data in a data structure that can be analyzed by the vehicle-side system  4 . Each piece of ECU information may be described in the rewrite specification data in the order of younger group and in accordance with the order of ECUs in the group. For example, in  FIG. 242 , in a case where the group 1 is set to the “ADS” and the group 2 is set to the “BRK” first and is set to the “EPS” second, ECU information of the “ADS” is arranged first, ECU information of the “BRK” is arranged next, and ECU information of the “EPS” is arranged last in the ECU information field of the specification data. 
     In the specification data illustrated in  FIG. 250 , the “ECU ID” to the “transfer size” of the ECU information are examples of the target unit related information including the type of target ECU  19 , and correspond to the above-described hardware attribute information and software attribute information. The “update program version” to the “write bank” are examples of update data related information. The “rewrite environment” for the group of ECUs or the entire vehicle is an example of update process information for designating an update process in a vehicle. 
     In  FIG. 252 , the package generation process in the package generation unit  202  will be described. As described above, here, a description will be made of the package generation process for the vehicle of “vehicle type”=“aaa”. As illustrated in  FIG. 252 , the center device  3  starts the package generation unit  202  of the package management unit  3 A with an instruction from the operator as a trigger. The package generation unit  202  determines an update target “ECU SW ID” in the same manner as in step B 1  (C 1 ). The package generation unit  202  acquires each piece of data corresponding to the update target “ECU SW ID” from the ECU reprogramming data DB  204  and generates one piece of reprogramming data (C 2 ). For example, in  FIG. 243 , the package generation unit  201  acquires the integrity verification data of the new program, the update data that is difference data, the integrity verification data of the update data, the integrity verification data of the old program, the rollback data that is difference data, and the integrity verification data of the rollback data, and generates the reprogramming data. The generated reprogramming data and the corresponding rewrite specification data described in steps B 1  to B 6  are integrated to generate a single distribution package file (C 3 ). Next, integrity verification data for the generated package file is generated (C 4 ), and the integrity verification data is registered in the package DB  206  along with the package file (C 5 ). 
       FIG. 253  is an image diagram illustrating contents of the package file generated as described above. The image illustrates a case where update data or integrity verification data corresponding to the “ADS”, the “BRK”, and the “EPS” that are update targets are integrated into one piece of reprogramming data according to the ECU order, and a single distribution package file is generated by integrating the reprogramming data with rewrite specification data. Here, the rollback data may be included in the reprogramming data only in a case where a memory configuration of the update target ECU  19  is the single-bank. When the memory configuration is the double-bank or the suspend, the rollback data that is an old program may be omitted because rewriting is not performed on an active bank. 
     As described above, according to the present embodiment, data of an update program of the application program update target ECU  19  among a plurality of ECUs  19  mounted on the vehicle is stored in the ECU reprogramming data DB  204  of the center device  3 . The vehicle related information such as an “ECU ID” for each of a plurality of the ECUs  19  mounted on the vehicle and an “ECU SW ID” of an application program stored in the ECU  19  is stored in the configuration information DB  208  along with the type of vehicle. The attribute of the rewrite target ECU  19  and the update data related information related to update data are stored in the ECU metadata DB  205 . 
     The specification data generation unit  201  generates the specification data to be transmitted to the vehicle along with the update data to be written to the target ECU  19 , the specification data including the type, the attribute, the update data related information, and the information indicating the rewrite environment related to the data update for the target ECU  19  on the basis of the information stored in the configuration information DB  208  and the ECU metadata DB  205 . The package generation unit  202  generates the distribution package including the specification data and the reprogramming data, and registers the distribution package in the package DB  206 . The package distribution unit  203  distributes the registered distribution package to the vehicle-side system  4 . Thus, the vehicle-side system  4  receives the specification data transmitted along with the update data, and can thus appropriately select the target ECU  19  on the basis of the specification data, and appropriately control a write process by using the update data. 
     Since the specification data generation unit  201  generates specification data for a plurality of ECUs  19  as one file, and the package generation unit  202  further packages the file into one file along with the reprogramming data for the plurality of ECUs  19 , the vehicle-side system  4  can write the update data into the plurality of ECUs  19  when a single distribution package is received. 
     Since the vehicle related information as the specification data includes group information in which some of a plurality of ECUs  19  are grouped, the vehicle-side system  4  can select a target ECU  19  according to an order defined by the group information, and can write update data. For example, when there are a plurality of ECUs  19  that are improvement targets of a certain function, by setting the group 1 as the body system ECU  19 , the group 2 as the traveling system ECU  19 , and the group 3 as the MM system ECU  19 , program update in the vehicle-side system  4  can be divisionally executed three times. Therefore, the waiting time of a user for each update time can be shortened compared with a case where the program update is executed collectively in all the ECUs. 
     Since the rewrite environment information includes the “vehicle condition (IG ON state)” and the “battery load” related to the vehicle and the “bus load table” related to the ECU  19 , the vehicle-side system  4  can determine a timing or the like for writing update data on the basis of the information. That is, a service provider using the OEM or the center device  3  can operate flexible program update by designating execution restriction conditions for the vehicle as the rewrite environment information. 
     Since the specification data generation unit  201  generates specification data in accordance with predetermined data structures in order by using information related to the ECU  19  having the earlier rewrite order set in advance, the vehicle-side system  4  can write update data in accordance with the location order of ECU IDs in the specification data. That is, since the ECUs  19  having mutually cooperative process are grouped into one group and an ECU order is defined by considering a content of the mutually cooperative process, even in a case where an update timing to the new program is not completely synchronized in the vehicle-side system  4 , the program update can be completed without inconvenience. For example, in a case where a new program of the ECU (ID 1 ) has a process of transmitting a predetermined message to the ECU (ID 2 ), and a new program of the ECU (ID 2 ) has a process of generating a timeout error when the predetermined message transmitted from the ECU (ID 1 ) cannot be received, it is preferable to define an ECU order such that the ECU (ID 1 ) is subjected to update first and the ECU (ID 2 ) is subjected to update later. 
     Second Embodiment 
     As illustrated in  FIG. 254 , the second embodiment relates to “vehicle configuration information synchronization” that is initially transmitted from the vehicle-side system  4  to the center device  3  in  FIG. 241 . When, on the vehicle side, the IG switch  37  is turned on, the CGW  13  transmits a “synchronization initiation request” to the DCM  12  with the turning-on as a trigger. The DCM  12  receives the synchronization initiation request, and returns a “configuration information collection request” to the CGW  13 . The CGW  13  inquires each ECU  19  for a program version. Each ECU  19  returns an “ECU SW ID” to the CGW  13 . The ECU  19  of which a memory configuration is the double-bank or the suspend also returns bank information indicating which of a plurality of banks is an active bank and which is an inactive bank to the CGW  13 . Each ECU  19  may also transmit calibration information of a control target actuator or the like, license information for receiving a program update service, and a trouble code occurring in the ECU  19  to the CGW  13 . 
     When reception of the “ECU SW ID” from each ECU  19  is completed, the CGW  13  transmits all the pieces of information to the DCM  12  along with the “VIN”. In this case, the “Vehicle SW ID” and the “Sys ID” managed by the CGW  13  may also be transmitted to the DCM  12 . The DCM  12  receives the information, and generates a single hash value that is a digest value for all of the “ECU SW IDs” by using, for example, a hash function. As described above, in a case where SHA-256 is used as the hash function, data values obtained by serially connecting values of all of the “ECU SW IDs” to each other are divided into message blocks every 64 bytes, the data values of the first message block is applied to an initial hash value to obtain a hash value with 32-byte length, and the data values of the succeeding message block is sequentially applied to the hash value, and, finally, a hash value of 32-byte length is obtained. Here, the DCM  12  may generate a single hash value not only for all of the “ECU SW IDs” but also for values including the “Vehicle SW ID”, the “Sys ID”, the bank information, and the calibration information. 
     The DCM  12  transmits the digest value of the “ECU SW ID” obtained as described above to the center device  3  along with the “VIN”. The DCM  12  may transmit the trouble code or the license information along with the digest value. Hereinafter, the digest value may be referred to as a “configuration information digest”, and all data values of the “ECU SW IDs” that are a basis thereof may be referred to as “configuration information all”. The “configuration information all” may include the “Vehicle SW ID”, the “Sys ID”, the bank information, and the calibration information. 
     As will be described later, the center device  3  compares digest values or updates the individual vehicle information DB  213 . The center device  3  synchronized with the configuration information checks availability of program update, and notifies the vehicle-side system  4  of the campaign information in a case where the program update is available. Thereafter, the vehicle-side system  4  downloads a distribution package, installs the distribution package in the target ECU  19 , and activates a new program. The CGW  13  transmits a “synchronization initiation request” to the DCM  12  with completion of the update process as a trigger, and then performs the same process as described above until a synchronization completion notification is performed. The above-described process that is performed with turning-on of the IG switch  37  as a trigger may also be performed after the program is updated. 
     As illustrated in  FIG. 255 , when the “configuration information digest” is received from the vehicle-side system  4  (D 1 ), the individual vehicle information management unit  3 C of the center device  3  collates the “configuration information digest” with a “configuration information digest” of a corresponding vehicle registered in the individual vehicle information DB  213  at that time, and determines whether or not both of the digests match each other (D 2 ). As the “individual vehicle information digest”, a value calculated in advance may be registered in the individual vehicle information DB  213 , or a digest value may be calculated by using the configuration information registered in the individual vehicle information DB  213  at the time of reception from the vehicle-side system  4 . When both of the digests match each other (YES), it is determined whether or not the individual vehicle information of the vehicle conforms to an approved combination registered in the configuration information DB  208  (D 6 ). Since there is a probability that the configuration information DB  208  may be updated at a predetermined timing, the determination in step D 6  is performed both in a case where both of the digests match each other in step D 2  (YES) and in a case where both of the digests do not match each other (NO). 
     Here, for example, as illustrated in  FIG. 256 , in order to determine the conformity, it is checked whether or not the combination of the “Vehicle SW ID” and the “ECU SW ID” of the configuration information uploaded from the vehicle-side system  4  is approved. In a list illustrated in the same figure, an “ECU SW ID” of “ECU ID=ADS” corresponding to “Vehicle SW ID=0001” registered in the configuration information DB  208  is “ads_001”, an “ECU SW ID” of “ECU ID=BRK” is “brk_001”, and an “ECU SW ID” of “ECU ID=EPS” is “eps_010”. 
     In contrast, the vehicle C with VIN=300 is also “Vehicle SW ID=0001”, but an “ECU SW ID” of “ECU ID=ADS” is “ads_002” and an “ECU SW ID” of “ECU ID=BRK” is “brk_003”. These two ECUs  19  are different from the configuration information registered in the configuration information DB  208 . Therefore, in step D 6 , “NO”, that is, it is determined to be disapproved and “NG”, and the configuration information check unit  210  notifies the vehicle-side system  4  and the management device  220  illustrated in  FIG. 241  that is a device managing information regarding a vehicle produced by the OEM or the like, of an abnormality (D 12 ). The notification of the abnormality is performed by, for example, the SMS transmission control unit  212  by using an SMS. The SMS transmission control unit  212  is an example of a communication unit. Even when the two ECUs  19  are not update target ECUs using new programs, the center device  3  determines that the vehicle is disapproved, and does not perform the processes in step D 7  and the subsequent steps. 
     On the other hand, the vehicle A with VIN=100 has “Vehicle SW ID=0001”, the “ECU SW ID” of “ECU ID=ADS” is “ads_001”, and the “ECU SW ID” of “ECU ID=BRK” is “brk_001”, all of which match the configuration information registered in the configuration information DB  208 . Therefore, in step D 6 , “YES”, that is, it is determined to be approved and “OK”, and the process proceeds to step D 7 . Here, the configuration information check unit  210  may determine whether the combination of “ECU SW IDs” of the vehicle C is present in the configuration information DB  208  to determine whether the vehicle C is approved or disapproved. The “Sys ID” may also be used for determination in addition to the “Vehicle SW ID”. 
     Next, the update availability check unit  211  accesses the campaign DB  217  via the campaign management unit  3 D to check availability of update using a new program (D 7 ). The availability of update is determined by comparing the “Vehicle SW ID” uploaded from the vehicle-side system  4  with the “pre-update Vehicle SW ID” of the campaign DB  217 . For example, as illustrated in  FIG. 23 , since the vehicle A with VIN=100 has “Vehicle SW ID=0001” before the update, it is determined that the update is available in the vehicle A (YES). In this case, the update availability check unit  211  notifies the vehicle-side system  4  of the vehicle A of the corresponding campaign ID “Cpn_001” (D 8 ). The campaign information corresponds to update notification information, and the campaign DB  217  is an example of an update notification information storage unit. 
     When the campaign DB  217  stores “Sys IDs” before and after update, availability of the update can be checked by using the “Sys IDs”. Instead of the “Vehicle SW ID”, the uploaded “ECU SW ID” list may be compared with the “pre-update ECU SW ID list” of the campaign DB  217  to determine update availability. 
     The vehicle-side system  4  acquires a campaign file corresponding to the ID from the center device  3  by using the notified campaign ID as a key (D 9 ). The campaign file includes text statements that describe a campaign content, restrictions on execution of program update, and so on. The restrictions are conditions for executing download or installation, and include, for example, a remaining battery charge, a free capacity of the RAM required for downloading a distribution package, and the current position of the vehicle. The vehicle-side system  4  analyzes the campaign file and displays the campaign content by using the in-vehicle display  7 . The user refers to a message displayed on the in-vehicle display  7  according to the campaign content, and decides whether or not to update an application program of the ECU  19 . When the user&#39;s approval operation is received via the in-vehicle display  7 , the CGW  13  notifies the center device  3  of the approval for the update via the DCM  12 . The center device  3  transmits the distribution package file with the package ID corresponding to the campaign ID and the integrity verification data to the vehicle-side system  4  (D 10 ). 
     When the update is unavailable in step D 7  (NO), the vehicle-side system  4  is notified of “update unavailable” (D 11 ). For example, as illustrated in  FIG. 256 , since the vehicle A with VIN=200 has “Vehicle SW ID=0002” after update which does not match any of the “pre-update Vehicle SW IDs” of the campaign DB  217 , it is determined that the update is unavailable. 
     On the other hand, when the collation result of the “configuration information digest” shows mismatch (NO) in step D 2 , the center device  3  requests the vehicle-side system  4  to transmit the “configuration information all” (D 3 ). This transmission corresponds to an “entire data transmission request notification”. When the vehicle-side system  4  transmits the “configuration information all” in response to the request, the center device  3  receives the “configuration information all” (D 4 ). The individual vehicle information management unit  3 C of the center device  3  updates the information regarding the vehicle registered in the individual vehicle information DB  213  (D 4 ). The process proceeds to step D 6 . The individual vehicle information DB  213  is an example of a vehicle-side configuration information storage unit. The CGW  13  may transmit the “synchronization initiation request” at a timing at which the IG switch  37  is turned off. 
     As described above, according to the second embodiment, when configuration information regarding a configuration of each ECU  19  is received from a plurality of ECUs  19 , the vehicle-side system  4  generates a hash value on the basis of data values of a plurality of pieces of configuration information, and transmits the hash value to the center device  3 . The center device  3  includes the individual vehicle information DB  213 , and compares the hash value transmitted from the vehicle-side system  4  with a hash value of the vehicle configuration information stored in the individual vehicle information DB  213 . When both of the values do not match each other, a request for transmission of “configuration information all” is transmitted to the vehicle-side system  4 . The vehicle-side system  4  receives the transmission of the request, and transmits the “configuration information all” to the center device  3 . When the “configuration information all” is received, the center device  3  updates the configuration information stored in the individual vehicle information DB  213  on the basis of data values thereof. 
     With this configuration, the vehicle-side system  4  initially transmits the hash value of the configuration information to the center device  3 , and transmits all data values of the configuration information to the center device  3  only when a comparison result of the hash values in the center device  3  shows mismatch. Consequently, since a size of data transmitted from the vehicle-side system  4  can be reduced, even when the vehicle-side system  4  is mounted on a plurality of vehicles, it is possible to reduce a total amount of communication. In particular, in a case where the configuration information is uploaded at a predetermined timing such as IG-on in the vehicle-side system  4 , a time period in which the communication concentrates may occur. Thus, an amount of transmitted data is reduced by using a hash value, and thus it is possible to reduce a communication load. 
     The CGW  13  receives the configuration information from all the rewrite target ECUs  19  of update data, and generates a hash value on the basis of all data values thereof, and the DCM  12  transmits the hash value at a timing at which the ignition switch  37  of the vehicle is turned on or off. Therefore, it is possible to transmit the hash value to the center device  3  at a timing at which traveling of the vehicle is initiated or finished. Thus, the center device  3  can appropriately synchronize the configuration information of the individual vehicle information DB  213  with that of the vehicle. 
     When an “ECU SW ID” of each ECU  19  is received from a plurality of ECUs  19 , the vehicle-side system  4  transmits a configuration information list in which a “Vehicle SW ID” is combined therewith to the center device  3 . The center device  3  compares the “ECU SW ID” list transmitted from the vehicle-side system  4  with an approved “ECU SW ID” list of a corresponding vehicle stored in the configuration information DB  208 ″, and transmits abnormality detection to the vehicle-side system  4  and the management device  220  when it is determined that the transmitted lists of combinations are disapproved. 
     With this configuration, the center device  3  can detect, as an abnormality, that a combination of the configuration information of the vehicle is in a state in which the plurality of ECUs  19  cannot cooperate with each other and traveling of the vehicle is hindered, and notify the vehicle-side system  4  of the abnormality. Thus, the vehicle-side system  4  can perform measures such as prohibiting traveling of the vehicle. 
     The center device  3  does not perform the update availability check process (D 7 ) on a vehicle in which a combination of vehicle configuration information is disapproved. Thus, it is possible to prevent program update from being executed in a disapproved vehicle. Even when the disapproved ECU  19  is not an update target ECU of a new program, the center device  3  does not execute the update availability check process (D 7 ). In the vehicle-side system  4 , when program update is executed, control for the ECU  19  which is not an update target is also generated. Therefore, in a vehicle having a disapproved ECU  19 , there is a probability that the program update may not be normally completed, and thus the center device  3  prevents the program update from being executed in the vehicle. 
     The center device  3  includes the campaign DB  217  in which the campaign information used to notify the vehicle side that update using a new program has occurred is stored, and, for a vehicle determined to be approved, checks availability of the campaign information of the corresponding vehicle. When the update is available, the campaign information is transmitted to the vehicle-side system  4 . Consequently, the campaign information can be presented to a user, and thus update of an application program can be prompted. Synchronization of the configuration information, determination of whether or not the configuration information is approved, and checking of update availability are executed as a series of processes by the center device  3  with upload of the configuration information from a vehicle as a trigger, and thus it is possible to promptly notify an adequate vehicle of update of a program. 
     The second embodiment may be modified and implemented as follows. 
     The center device  3  may transmit the “synchronization initiation request” to the vehicle-side system  4 , and the DCM  12  may transmit the “configuration information collection request” to the CGW  13  when the “synchronization initiation request” is received. For example, when the configuration information DB  208  of “vehicle type=aaa” is updated, the center device  3  transmits the “synchronization initiation request” to a vehicle of the vehicle type. 
     The hash value may be transmitted to the center device  3  at a timing when rewriting is completed in the rewrite target ECU  19  of the update data. That is, the flowchart of steps D 1  to D 12  illustrated in  FIG. 255  is executed even when update of programs of all the rewrite target ECUs  19  is completed. 
     The center device  3  requests the vehicle-side system  4  to transmit a combination list of the configuration information of the respective ECUs  16  when a comparison result of both hash values shows match. When the combination list is received, the processes in steps D 6  to D 12  may be performed. 
     Even when the comparison result of both of the hash values shows match, the center device  3  may refer to the campaign DB  217  to check availability of the campaign information of a corresponding vehicle. 
     The transmission of a hash value from the vehicle-side system  4  to the center device  3  may be performed as illustrated in  FIG. 256 .  FIG. 256  is a flowchart illustrating a process in the CGW  13 . For example, when the IG switch  37  is turned on, the CGW  13  collects configuration information from each ECU  19  (D 21 ), and generates a hash value for data values of the collected configuration information (D 22 ). The generated hash value is compared with a hash value (previously generated value) stored in the flash memory  24   d , and thus it is determined whether or not there is a difference therebetween (D 23 ). When there is a difference (YES), the hash value generated this time is stored in the flash memory  24   d  (D 24 ), and the hash value is transmitted to the center device  3 . When there is no difference between both of the hash values in step D 23 , the process is finished (NO). A hash value for initial values of the configuration information is assumed to be stored in advance in the flash memory  24   d . As a result, the number of times of uploading the configuration information from the vehicle-side system  4  to the center device  3  can be reduced. 
     Third Embodiment 
     The third embodiment relates to a function executed by a campaign management unit  3 D of the center device  3  in order to improve a rate of updating an application program in the vehicle-side system  4 . As illustrated in  FIG. 258 , for example, in the vehicle-side system  4 , a user sets an HTTP polling interval to about three days by using a Config files, and thus the vehicle-side system  4  periodically checks update availability of an application program with respect to the center device  3 . Consequently, when the update is checked after the campaign information of a VIN of a vehicle corresponding to the campaign DB  217  is set, the center device  3  notifies the vehicle-side system  4  that “the update is available”. That is, as described in the second embodiment, the process in which the center device  3  checks the update with upload of the configuration information using HTTP from the vehicle-side system  4  as a trigger is executed at the timing of IG-on after three days have elapsed. 
     In above-described way, in the configuration in which update availability is checked with a notification from a vehicle as a trigger, the center device  3  does not need to transmit campaign information from the center device  3  to all the vehicles that are campaign targets at the time at which the campaign information is set. However, in a case where a user does not use a vehicle for a long period of time, the user does not check update availability using HTTP during that time. Thus, it is supposed that the user does not know that a new campaign has been issued, and an application program may not be updated in the vehicle. 
     Therefore, as illustrated in  FIG. 259 , the SMS transmission control unit  212  of the center device  3  checks an access log of each vehicle by referring to the individual vehicle information DB  213  at regular or predetermined timings (E 1 ). It is determined whether or not there is a vehicle that has not made access to the center device  3 , that is, a vehicle that has not transmitted configuration information for checking update of an application program for a predetermined period (E 2 ). The predetermined period is, for example, about seven days, with the day when a new campaign is set in the campaign DB  217  as the starting day of reckoning. That is, the SMS transmission control unit  212  specifies a vehicle in which update has not been checked for seven days, for vehicles of which “Vehicle SW IDs” of the individual vehicle information DB  213  correspond to “pre-update Vehicle SW IDs” of the campaign DB  217 . The SMS transmission control unit  212  may specify a vehicle in which update has not been checked for a predetermined period for all the vehicles. 
     In the individual vehicle information DB  213 , initial data is registered by the OEM when a vehicle is produced in a factory, and, thereafter, an initial access log is input due to a notification from the OEM in response to, for example, sales of the vehicle. This access log substantially corresponds to a notification for validating subsequent program update. A vehicle for which an access log has not been input is excluded from the determination in step E 2 . 
     When there is a vehicle for which the update has not been checked for a predetermined period (YES), the SMS transmission control unit  212  determines characteristics of the vehicle on the basis of the vehicle type in the individual vehicle information DB  213 , equipment information, and the like (E 3 ). Here, as the characteristics, the SMS transmission control unit  212  determines whether the vehicle is an electric vehicle, an EV capable of receiving a short message service (SMS), a conventional gasoline engine vehicle capable of receiving an SMS, that is, a conventional engine vehicle (conventional vehicle), or a vehicle for which it is difficult to receive an SMS. For example, in a case where the DCM  12  mounted on the vehicle does not have a function of receiving an SMS or does not have a contract for receiving an SMS, it is determined that it is difficult for the vehicle to receive an SMS. 
     In a case of the EV, an SMS for initiating a configuration information transmission sequence by starting the ECU  19  of the vehicle is transmitted (E 5 ; refer to  FIG. 260 ). When the DCM  12  receives the SMS and executes a command described in the SMS, the IG-on power supply state is entered, and the started CGW  13  transmits the configuration information to the center device  3  via the DCM  12 . Thereafter, as in steps D 1  to D 12  illustrated in  FIG. 255 , update is checked, and a distribution package or the like is downloaded. In the case of the EV, since a capacity of the battery is large, it is considered that it is sufficiently possible to download the program in the IG-on power supply state in the parking state. Therefore, the ECU  19  is started by using an SMS, and a sequence after update check and download is automatically initiated. 
     In a case where a remaining battery charge of the battery of the EV vehicle is small, the vehicle-side system  4  refers to the rewrite specification data illustrated in  FIG. 250 , and, in a case where a remaining battery charge is smaller than a designated quantity, installation is controlled not to be initiated. Alternatively, in a case where a remaining battery charge described as restrictions in the campaign file transmitted by the center device  3  in step D 9  is referred to and is smaller than a designated remaining battery charge, the vehicle-side system  4  is controlled not to initiate download of the distribution package. 
     In the conventional vehicle, the SMS transmission control unit  212  transmits an SMS that is displayable on the in-vehicle display  7  to a vehicle which is ready to receive the SMS in a period in which the DCM  12  is intermittently started (E 4 ; refer to  FIG. 260 ). For example, the CGW  13  instructs the in-vehicle display  7  to display text statements described in the received SMS at the next IG-on timing. In a case where information of the user&#39;s mobile terminal  6  is registered in the individual vehicle information DB  213 , the SMS may be transmitted to the mobile terminal  6 . For example, a text message is displayed, such as “there is campaign information; and execute IG-on” The individual vehicle information DB  213  is an example of a user information storage unit. On the other hand, a vehicle in a state in which an SMS is difficult to receive is not subjected to anything, and coping is performed, for example, by separately sending a mail to a user (E 6 ). 
     As described above, according to the third embodiment, the vehicle-side system  4  transmits the configuration information of a plurality of ECUs  19  to the center device  3 , and the individual vehicle information DB  213  stores the configuration information transmitted from the respective vehicles along with the transmission date thereof. The campaign DB  217  stores, as campaign information, a target VIN list for identifying a campaign ID and a data update target vehicle. The center device  3  refers to the individual vehicle configuration DB  213 , and, when there is no transmission of the configuration information within a predetermined period from the transmission date linked to a target vehicle, transmits a message for prompting data update to the vehicle-side system  4  of the target vehicle by using an SMS. 
     With this configuration, even in a case where the situation is continued in which the configuration information is not transmitted to the center device  3  because a user does not have an opportunity to ride on a vehicle, the center device  3  transmits a message for prompting data update to the vehicle-side system  4  of the target vehicle when a predetermined period has elapsed from the transmission date stored in the individual vehicle information DB  213 . Therefore, the user can recognize that the data update is necessary by referring to the message. 
     The center device  3  refers to the individual vehicle information DB  213  and the campaign DB  217  to determine a program update target vehicle. That is, the individual vehicle information DB  213  stores the date on which the configuration information is transmitted from each vehicle, and the campaign DB  217  stores a target VIN list. Therefore, the center device  3  can determine a program update target vehicle on the basis of the transmission date of the configuration information from each vehicle and the target VIN list. 
     When the configuration information is received from each ECU  19  with turning-on of the ignition switch  37  as a trigger, the vehicle-side system  4  transmits the configuration information to the center device  3 . Therefore, when the user rides on the vehicle, the configuration information can be reliably transmitted to the center device  3 . 
     When the target vehicle is an electric vehicle, the center device  3  transmits a message including a command for starting an ECU of the target vehicle, and the vehicle-side system  4  having received the message starts the ECU  19  to execute a process related to data update. That is, since the electric vehicle has a relatively large capacity of the battery, the ECU  19  can execute processes related to data update without waiting for a user operation. Therefore, it is possible to execute the data update efficiently. 
     When the target vehicle is a conventional vehicle, the center device  3  transmits at least text information displayable on the in-vehicle display  7  of the target vehicle as a message. Therefore, a user of the conventional vehicle can recognize that the data update is necessary by referring to the text information displayed on the in-vehicle display  7 . 
     When a transmission destination of the user&#39;s mobile terminal  6  is stored in the individual vehicle information DB  213 , the center device  3  transmits text information displayable on the mobile terminal  6  as a message. As a result, the user can recognize that the data update is necessary by referring to the text information displayed on the mobile terminal  6  even when there is no opportunity to ride on the vehicle. 
     When the user transmits the transmission date and a transmission destination of a campaign to the center device  3  in advance via the mobile terminal  6 , the center device  3  stores the transmission date and the transmission destination in the individual vehicle information DB  213 . For example, the user designates the day after the campaign is issued as the transmission date, and designates the mobile terminal  6  as the transmission destination instead of the in-vehicle display  7 . The user designates a predetermined time at which the user does not ride as the transmission date, designates the vehicle as the transmission destination, and performs an operation of approving that a program is automatically updated. Consequently, the center device  3  transmits the campaign information to the transmission destination on the transmission date regardless of whether or not the configuration information is transmitted. Therefore, when the user knows in advance that there is no opportunity to ride on the vehicle for a while, the campaign information can be set to be received on the transmission date set by the user. 
     The third embodiment may be modified and implemented as follows. 
     The user information storage unit may be provided separately from the individual vehicle information DB  213 . 
     The campaign information may be transmitted by using means other than SMS. 
     Instead of storing the transmission date in the individual vehicle information DB  213 , the center device  3  may store, for example, a day on which no data is transmitted from the vehicle, and may transmit a message for prompting data update when the day continues for seven consecutive days. 
     Fourth Embodiment 
     The fourth embodiment relates to a case where a user designates campaign information and a message notification method. For example, a case is supposed that the user does not ride for about one month, and that it is determined in advance that there is no opportunity to turn on the IG switch  37 . As illustrated in  FIG. 261 , the user transmits settings of a notification destination and the notification date and time at the time of occurrence of a campaign to the center device  3  by using the mobile terminal  6 . For example, it is set that the mobile terminal  6  will be notified of campaign information one month later. Consequently, the individual vehicle information management unit  3 C stores information indicating the notification destination and the notification date and time in the individual vehicle information DB  213 , and notifies the user of the information according to the settings. For example, when two campaigns (1, 2) are set during one month, the SMS transmission control unit  212  notifies the user&#39;s mobile terminal  6  of information regarding the campaigns (1, 2) one month later to prompt program update. 
     As described above, according to the fourth embodiment, when the user transmits the transmission date and a transmission destination of campaign information to the center device  3  via the mobile terminal  6 , the center device  3  stores the transmission date and the transmission destination in the individual vehicle information DB  213 . The center device  3  transmits the campaign information to the transmission destination on the stored transmission date. Consequently, it is possible to stop transmission of unnecessary campaign information from the center device  3  when it is determined that the user does not ride on the vehicle for a certain period. 
     Fifth Embodiment 
     The fifth embodiment relates to a function of adding verification data used for the vehicle-side system  4  to verify the integrity of data when the center device  3  transmits data of an update program to the vehicle-side system  4 . As illustrated in  FIGS. 262 and 263 , a supplier creates data to be registered in the ECU reprogramming data DB  204  by using the package management unit  3 A. Specifically, the package management unit  3 A creates new difference data for rewriting an old program to a new program as update data (Y 1 ), and creates a hash value that is integrity verification data for the new program of the ECU  19  and a hash value for the new difference data (Y 2 ). Here, in a case where the ECU has a single-bank memory, old difference data for rewriting the new program to the old program as rollback data may be created, and a hash value for the old program for the ECU  19  and a hash value for the old difference data may be created. 
     The package management unit  3 A generates an authenticator by applying encryption using a key value which is a predetermined key for each hash value (Y 3 ). The package management unit  3 A transmits the update data and the integrity verification data with each authenticator, and stores the transmitted data in the ECU reprogramming data DB  204  (Y 4 ). As described above, the package management unit  3 A generates a package, generates integrity verification data for the package, and transmits the integrity verification data to the vehicle-side system  4  (Y 5 ). 
     The master device (OTA master)  11  calculates the integrity verification data for the package, compares a calculated value with the integrity verification data of the received package, and verifies the integrity of the package (Y 6 ). When the package integrity verification is successful, the master device  11  transmits the update data and the integrity verification data of the ECU to the rewrite target ECU  19  (target ECU) (Y 7 ). 
     The rewrite target ECU  19  calculates the integrity verification data for the update data, compares a calculated value with the integrity verification data of the received update data, and verifies the integrity of the update data (Y 8 ). When the update data integrity verification is successful, the rewrite target ECU  19  restores the difference data that is the update data and writes the data into the flash memory  28   d  (Y 9 ). When the writing is completed, the rewrite target ECU  19  calculates the integrity verification data for the data written in the flash memory  28   d , compares a calculated value with the integrity verification data of the received new program, and verifies the integrity of the flash memory  28   d  (Y 10 ). The rewrite target ECU  19  transmits the verification result to the master device  11  (Y 11 ), and the master device  11  transmits the received verification result to the center device  3  as an installation result notification (Y 12 ). 
     For example, as illustrated in  FIG. 243 , the package management unit  3 A generates the following integrity verification data for the latest “ECU SW ID”. In a case where a memory configuration of the ECU is the double-bank memory or the suspend, the following (3) and (4) may be omitted. 
     (1) A hash value that is integrity verification data for a new program of the ECU is generated. A functional portion for performing this process is an example of a first verification value generation unit (step A 1 ).
 
(2) Update data that is difference data for update to a new program on the basis of an old program of the ECU, and a hash value that is integrity verification data of the update data, are generated. The functional portion for performing this process is an example of a second verification value generation unit in step A 4 .
 
(3) A hash value that is the integrity verification data for the old program of the ECU is generated. A functional portion for performing this process is an example of a fourth verification value generation unit in step A 5 .
 
(4) Update data that is difference data for update to the old program on the basis of the new program of the ECU, and a hash value that is integrity verification data of the update data, are generated. A functional portion for performing this process is an example of a fifth verification value generation unit in step A 7 .
 
     The “program” includes constant data to be used in the program. When “ECU SW ID=ads_002”, a hash value xl is generated for update data “Adsfile001-002”. As a hash function, for example, SHA-256 is used as described above. The hash value corresponds to a verification value. Here, the package management unit  3 A may be configured to generate integrity verification data with an authenticator by generating an authenticator by applying encryption by using a key value that is a predetermined key to the hash value. 
     Next, the supplier generates integrity verification data with an authenticator by applying encryption using a key value that is a predetermined key to the integrity verification data, and provides the OEM with the update data and the integrity verification data with the authenticator in correlation with each other. In other words, the package management unit  3 A provides the OEM with each program and integrity verification data with an authenticator for the program registered in the ECU reprogramming data DB  204 . In response to an instruction from the OEM, the package management unit  3 A generates rewrite specification data as described above by using the ECU reprogramming data DB  204  or the like, generates a distribution package, and registers it in the package DB  206 . When a download request for update data is generated from the vehicle-side system  4 , the center device  3  distributes a distribution package including the update data and the integrity verification data with the authenticator to the vehicle-side system  4  in response to the download request. The “integrity verification data” in the claims includes both a hash value only and integrity verification data with an authenticator including encryption using a key. 
     When the distribution package is received, the master device  11  of the vehicle-side system  4  verifies the validity of the distribution package by using the integrity verification data (third verification value) added to the distribution package. Specifically, integrity verification data calculated by using the distribution package is compared with the received integrity verification data, and, when the pieces of data match each other, it is determined to be normal. When it is checked that the distribution package is normal as a result of the verification, the master device  11  unpackages the distribution package into data for each ECU (refer to  FIG. 239 ). The master device  11  transfers the update data and the integrity verification data with the authenticator to the destination the ECU  19 . 
     The ECU  19  verifies the validity of the update data by using integrity verification data with the authenticator (second verification value). Specifically, the integrity verification data calculated by using the received update data is compared with the received integrity verification data, and when the data matches, it is determined to be normal. When it is checked to be normal as a result of the verification, the CPU  28   a  of the ECU  19  performs a write process on the flash memory  28   d . When the write process is completed, the ECU  19  uses the integrity verification data with the authenticator (first verification value) to read the data written in the flash memory  28   d  and verify its validity. Specifically, integrity verification data calculated by using the read data is compared with the received integrity verification data, and, when the pieces of data match each other, it is determined to be normal. The integrity verification data is stored in a predetermined area of the flash memory  28   d  for use when the ECU  19  is started. When these processes are completed, the ECU  19  transmits a write response to the master device  11 , including the verification results. The master device  11  notifies the center device  3  of an installation result. The “target ECU” in the figure is synonymous with a “target ECU” and the “OTA master” is synonymous with a “DCM”. The CPU  28   a  is an example of a write processing unit. 
     Here, in a case where program update cancellation occurs during installation, the ECU  19  performs a rollback process. The ECU  19  writes the update data and verifies the validity of the rollback difference data by using the integrity verification data with the authenticator (fifth verification value). Specifically, the integrity verification data calculated by using the rollback difference data is compared with the received integrity verification data, and when the data matches, it is determined to be normal. When it is checked to be normal as a result of the verification, the ECU  19  initiates writing using the rollback difference data after writing of the update data is completed. After the writing is completed, the ECU  19  reads the data written in the flash memory  28   d  by using the integrity verification data with the authenticator (fourth verification value), and verifies its validity. The integrity verification of the received difference data (the update data or the rollback difference data) may be performed by the master device  11  instead of the ECU  19 . 
     As illustrated in  FIG. 264 , thereafter, when the IG switch  37  of the vehicle is turned on, the ECU  19  performs data verification at the time of start with turning-on thereof as a trigger. The ECU  19  verifies the integrity of a started program or the like started by using the integrity verification data with the authenticator (the first verification value or the fourth verification value). First, in the flash memory  28   d , a hash function is applied to data values of an evaluation target area in which an updated program or constant data is written, and thus a hash value is acquired. Next, the integrity verification data with the authenticator is decrypted, and a hash value (expected value) included in the decryption result is collated with the acquired hash value (calculated value), and it is determined whether or not the program or the like written in the flash memory  28   d  has been falsified. When both hashes value match each other and thus it is determined to be “OK”, the ECU  19  performs a start process as usual. The same process is performed on each ECU  19 , and, when results in all the evaluation target ECUs  19  evaluated are “OK”, the process is finished. 
     On the other hand, when a result of verification for any ECU  19  is abnormal, that is, “NG”, the ECU  19  stores a log of the process and notifies the master device  11  of the error. The master device  11  similarly stores the log and notifies the center device  3  of the error. The center device  3  similarly stores the log and notifies the management device  220  of the OEM or the like of an error. The notification sent to the management device  220  is performed, for example, by the SMS transmission control unit  212  by using SMS, or through transmission of an e-mail via an Internet line. 
     In the embodiment described above, the vehicle-side system  4  is configured to verify the integrity. In  FIG. 265 , a description will be made of a case where verification of the integrity (comparison with an expected value) is performed by the center device  3 . In  FIG. 265 , for example, when version information of an updated application program is transmitted to the master device  11  at a timing of IG-on or the like, the ECU  19  generates and transmits integrity verification data with an authenticator in the same manner as described above along with the version information (X 1 ). The ECU  19  calculates integrity verification data for the data in the flash memory  28   d  and transmits the calculated value to the master device  11 . The master device  11  transmits configuration information including the integrity verification data with the authenticator to the center device  3  (X 2 ). 
     The center device  3  accesses the ECU reprogramming data DB  204 , acquires integrity verification data with an authenticator that matches the “ECU SW ID” of the target ECU  19  (X 3  and X 4 ), and verifies the acquired data with the integrity verification data uploaded from the vehicle (X 5 ). Specifically, integrity verification data of the new program corresponding to the “ECU SW ID” is acquired from the ECU reprogramming data DB and is collated with the uploaded integrity verification data. When a result of the collation is inconsistent, that is, NG (X 6 ; NG), the management device  220  of the OEM is notified of an abnormality (X 7 ). A function of this processing unit corresponds to an abnormality notification unit. 
     The center device  3  transmits the collation result to the master device  11  (X 8 ), and the master device  11  transmits the received collation result to the rewrite target ECU  19  (X 9 ). In a case where the collation result is OK, the rewrite target ECU  19  operates an application program as usual. In a case where the collation result is NG, the application program is not operated. In the present embodiment, the package management unit  3 A may omit the integrity verification data generation (step A 1 ) of a new program and the integrity verification data generation (step A 5 ) of an old ECU program. 
     In the above description, the ECU  19  verifies the integrity of update data at a timing at which the IG switch  37  of the vehicle is turned on after the update data is written, but, instead, the integrity of the update data may be verified immediately after the update data is written. 
     In the above embodiment, the integrity verification data with an authenticator is added to only update data, but this may be implemented as follows. 
     A new program and corresponding update data are acquired from the ECU reprogramming data DB  204  (data acquisition procedure; step A 1 ). 
     The first verification value generation unit generates a first hash value for the new program (first verification value generation procedure; step A 2 ). 
     The second verification value generation unit generates a second hash value for the update data (second verification value generation procedure; step A 4 ). The package generation unit  202  causes the update data, specification data, and the first and second hash values to be included in a distribution package (distribution package generation procedure). The update data correspond to new difference data. 
     The third verification value generation unit generates a third hash value for the distribution package (third verification value generation procedure; step C 4 ). 
     The package distribution unit  203  transmits the distribution package and the third hash value to the vehicle-side system  4 . 
     An authenticator may be added only to the distribution package and the third hash value, or may be added in each stage of generating each hash value. The package distribution unit  203  corresponds to a transmission unit. 
     In this case, in the vehicle-side system  4 : 
     The DCM  12  that is a reception processing unit receives the distribution packages and the third hashing values. 
     The third verification processing unit compares a hash value generated from the distribution package data with the received third hash value, and verifies the integrity of the distribution package data. 
     The second verification processing unit compares a hash value generated from the update data with the received second hash value, and verifies the integrity of the update data. 
     The CPU  28   a  that is an example of a write processing unit writes the update data into the flash memory  28   d.    
     The first verification processing unit writes the update data to generate a hash value for data values in the flash memory  28   d , serving as a new program, and compares the hash value with the received first hash value to verify the integrity of the new program. 
     When a verification result of the update data is NG, writing into the flash memory  28   d  is stopped. When a verification result of the new program written in the flash memory  28   d  is NG, the new program is invalidated, and a rollback process is performed as necessary. The first to third verification processing units may be realized by the CPU  28   a . When any of the verification results in the first to third verification processing units is NG, the DCM  12  as a transmission processing unit notifies the center device  3  of an abnormality. 
     In addition to the above configuration, as illustrated in  FIG. 243 , when rollback data for return to a state of the old program before the update data is written is present, the following process may be performed as follows. 
     The fourth verification value generation unit generates a fourth hash value for the old program (fourth verification value generation procedure; step A 5 ). 
     The fifth verification value generation unit generates a fifth hash value for the rollback data for returning the new program to the old program (fifth verification value generation procedure; step A 7 ). The rollback data indicates rollback difference data and corresponds to old difference data. 
     The package generation unit  202  causes the update data, the rollback difference data, rewrite specification data, and the first, second, third, and fourth hash values to be included in a distribution package (distribution package generation procedure). 
     In this case, in the vehicle-side system  4 , while the update data is rewritten into the flash memory  28   d , for example, when the user gives an instruction for stopping the rewriting, the rewriting is cancelled, and restoration to the old program, that is, rollback is performed. This corresponds to only a case where a memory configuration of the ECU  19  is a single-bank memory. 
     The second verification processing unit calculates a hash value for the rollback data included in the distribution package, compares the calculated hash value with the fifth hash value, and verifies the integrity of the rollback data. 
     The CPU  28   a  performs writing into the flash memory  28   d  by using the rollback data. 
     The first verification processing unit calculates a hash value for the old program restored through writing into the flash memory  28   d , compares the calculated hash value with the fourth hash value, and verifies the integrity of the old program. 
     As described above, according to the fifth embodiment, the ECU reprogramming data DB  204  stores new program of the target ECU  19  that is a rewrite target, an old program, and update data that is new difference data for update from the old program to the new program. The first verification value generation unit generates a first hash value by using the new program, and the second verification value generation unit generates a second hash value by using the update data. The package generation unit  202  generates a package including the update data, first and second verification values, and specification data for a plurality of target ECUs  19 . The third verification value generation unit generates a third hash value by using the distribution package, and the package distribution unit  203  transmits the distribution package to the vehicle-side system  4  along with the third hash value. 
     When the vehicle-side system  4  receives the distribution package and the third hash value, the third verification processing unit calculates a hash value for the distribution package and verifies the integrity of the distribution package by comparing the hash value with the third hash value. The second verification processing unit calculates a hash value for the update data corresponding to the target ECU  19  included in the distribution package, compares the hash value with the second hash value included in the distribution package, and verifies the integrity of the update data. 
     The CPU  28   a  writes the update data into the flash memory  28   d , and the first verification processing unit calculates a hash value for data of the updated new program in the flash memory  28   d , compares the hash value with the first hash value, and verifies the integrity of the data of the new program. Thus, each hash value can be used to verify the integrity of each data value in a plurality of stages. The integrity of the new program can be verified in triplicate, and thus it is possible to prevent the vehicle-side system  4  from writing an incomplete new program and operating with an incorrect new program. 
     When the rollback data is present in the ECU reprogramming data DB  204 , the fourth verification value generation unit generates a fourth hash value for the old program, and the fifth verification value generation unit generates a fifth hash value for the rollback data. The package generation unit  202  causes the update data, the first and second hash values, the rollback data, and the fourth and fifth hash values to be included in a distribution package. 
     When rollback is performed in the vehicle-side system  4 , the second verification processing unit calculates a hash value for the rollback data included in the distribution package, and verifies the integrity of the rollback data by comparing the hash value with the fifth hash value. The CPU  28   a  perform writing into the flash memory  28   d  by using the rollback data. The first verification processing unit calculates a hash value for the old program restored through writing into the flash memory  28   d , and verifies the integrity of the old program by comparing the hash value with the fourth hash value. Consequently, the integrity of the old program that has been rolled back can be verified. In the above description, the first to fifth verification value generation units are functional blocks in the package management unit  3 A of the center device  3 . The first, second, fourth, and fifth verification processing units are functional blocks in the target ECU  19  of the vehicle-side system  4 . The third verification processing unit is a functional block in the master device  11  of the vehicle-side system  4  (OTA master  11 ). 
     Modification Example 1 of First Embodiment 
     As illustrated in  FIGS. 266 and 267 , a plurality of packages “pkg_001_1” and “pkg_001_2” may correspond to one campaign “cpn_001”. A plurality of packages may be grouped into a plurality of groups. In the above-described embodiments, one package includes a plurality of groups. In the present modification example, one package is generated for one group, and a plurality of packages are distributed for one campaign. For example, the package “pkg_001_1” includes the “ADS” and the “BRK” which are ECUs belonging to the group 1, and the package “pkg_001_2” includes the “EPS” which is an ECU belonging to the group 2. 
     In this case, as illustrated in  FIGS. 268 and 269 , specification data and a distribution package are individually generated for each group. In  FIG. 268 , the specification data generation unit  201  generates, for example, first specification data describing ECU information of the “ADS” and the “BRK” as specification data of the group 1. The specification data generation unit  201  generates, for example, second specification data describing ECU information of the “EPS” as specification data of the group 2. In  FIG. 269 , the package generation unit  202  generates reprogramming data in which, for example, update data of the “ADS” and the “BRK” belonging to the group 1 are integrated according to an ECU order, and generates a package file “pkg001_1.dat” by integrating the generated reprogramming data with the first specification data. The package generation unit  202  generates reprogramming data by using update data of the “EPS” belonging to the group 2, and generates a package file “pkg001_2.dat” by integrating the generated reprogramming data with the second specification data. 
     Modification Example 2 of First Embodiment 
       FIG. 270  illustrates a process content in a case where the functions of the specification data generation unit  201  and the package generation unit  202  are integrated to configure one package generation tool  221 . Hereinafter, each process will be described again. 
     In the specification data generation process, a value input by an operator as specification data information is output in a data structure in which the number of bits or an order of arrangement is determined in advance, and specification data is generated. The specification data information is, for example, values exemplified in  FIG. 250 , and information in units of vehicles or systems (groups) is input in addition to information in units of ECUs such as the ECU (ID 1 ), the ECU (ID 2 ), and the ECU (ID 3 ). The information in units of vehicles is, for example, the rewrite environment information illustrated in  FIG. 250 , and the information in units of systems is, for example, the group information or the ECU order information illustrated in  FIG. 250 . Input information in units of vehicles and input information in units of systems may be different files. The specification data generation process may have a function of automatically calculating some values such as a file size of update data and reflecting the calculated values in specification data. 
     In the package generation process, generated specification data, update data of each ECU, and a value and a file input as integrity verification data for each ECU are output in a data structure in which the number of bits or the arrangement order is determined in advance, and a file of a distribution package is generated. The update data and the integrity validation data for each ECU are arranged in an ascending order of groups, or an ascending order of ECU orders. Here, in addition to the update data (new difference data), rollback data (old difference data) may also be input. As the integrity verification data, “integrity verification data of an ECU program (new)” and “integrity verification data of update data” are input. In a case where rollback data is also added, “integrity verification data of an ECU old program” and “integrity verification data of old difference data” are also input. 
     In the integrity verification data generation process, integrity verification data is generated for the generated package file as described in step C 4  of  FIG. 252 . 
     The generated package file or the integrity verification data generated for the package file is registered in the package DB  206  by an operator. 
     The functions executed by the center device  3  may be realized by hardware or software. The functions may be realized by hardware and software in cooperation. 
     The rewrite data may be not only an application program, but also data such as a map or data such as control parameters. 
     A content of the configuration information is not limited to the example, and may be appropriately selected according to individual design. 
     A content of the specification data is not limited to the example. 
     The campaign information and the distribution specification data may be included in a distribution package and transmitted to the vehicle side, or may be transmitted to the vehicle side separately from the distribution package. 
     In the fifth embodiment, the distribution package and the third verification value may be stored in the package storage unit in advance, and the package transmission unit  213  may transmit the distribution package and the third verification value linked to a request to the in-vehicle-side system  4  in response to the request from the in-vehicle-side system  4 . 
     According to the present embodiment, the following operations and effects can be obtained by performing the above-mentioned (8) rewrite execution control process. The rewrite target ECU  19  executes the installation during the vehicle being travelable or parked, and executes the activation during the vehicle being parked. It is possible to appropriately complete rewriting of a program. 
     When the rewrite target ECU  19  is the double-bank memory ECU, the rewrite target ECU  19  is instructed to execute the installation by the CGW  13  during the vehicle being travelable, and thus it is possible to execute the installation during the vehicle being travelable. When the rewrite target ECU  19  is the single-suspend memory ECU or the single-memory ECU, the rewrite target ECU  19  is instructed to execute the installation by the CGW  13  during the vehicle being parked, and thus it is possible to execute the installation during the vehicle being parked. 
     Although the present disclosure has been described in accordance with the embodiments, it is understood that the present disclosure is not limited to the embodiments and structures described above. The present disclosure encompasses various modification examples or variations within the scope of equivalents. Various combinations or forms as well as other combinations or forms including only one element, one or more elements, or one or less elements, fall within the scope or the spirit of the present disclosure. 
     The control unit and the method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor and a memory programmed to execute one or more functions embodied by a computer program. Alternatively, the control unit and the method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described in the present disclosure may be realized by one or more dedicated computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured by one or more hardware logic circuits. The computer program may also be stored on a computer readable and non-transitory tangible recording medium as instructions executed by a computer.