Patent Publication Number: US-2010124230-A1

Title: Terminal apparatus and program

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority from Japanese Patent Application No. 2008-296093 filed on Nov. 19, 2008, and Japanese Patent Application No. 2009-64991 filed on Mar. 17, 2009, which is herein incorporated by reference in its entirety. 
     BACKGROUND 
     1. Field 
     Various embodiments of the present invention relate to a terminal apparatus to transmit and receive information such as motion pictures, music, images, and programs (hereinafter, denoted as “contents”). 
     2. Description of the Related Art 
     In contrast to a client-server type (C-S type), a P2P system capable of relaying messages between information processing apparatuses (nodes) without going through a specific server apparatus is proposed. 
     The P2P system has an advantage in that there is no need to install a specific server that manages information in a unified way like the C-S type because when a search request of information is received, a search processing according to the search request is not only performed in the local node, but also the search request is transferred to other nodes. 
     Japanese Patent Application Laid-Open No. 2008-020938 describes an information sharing system including a plurality of node apparatuses mutually communicable via a network and a storage instruction apparatus that causes the plurality of node apparatuses to store a plurality of pieces of shared information shared among the plurality of node apparatuses. 
     The storage instruction apparatus in the information sharing system includes a shared information acquisition unit that acquires shared information that is input into the information sharing system and made sharable by the plurality of node apparatuses, an advance reservation information acquisition unit that acquires advance reservation information containing at least one piece of node apparatus identification information to identify the node apparatus that has made a purchase reservation of the acquired shared information, and a storage instruction unit that sends out the acquired shared information and storage instruction information that instructs storage of the shared information to the node apparatus identified based on node apparatus identification information contained in the advance reservation information. 
     Accordingly, the node apparatus that makes a purchase reservation of newly input shared information is instructed to store the contents in such a way that the contents are maintained sharably with other node apparatuses and therefore, after shared information is made public, there is no need for the node apparatus that makes a purchase reservation to receive delivery from other node apparatuses by performing a search of the shared information. 
     As a result, an increase in load on a specific node apparatus is assumed to be preventable after shared information is made public. 
     SUMMARY 
     According to an aspect of the embodiment described bellow, a terminal apparatus connectable as a node apparatus to an information sharing system having a plurality of node apparatuses mutually communicable via a network. 
     The terminal apparatus accepts an operation to reserve reception of contents, transmits reservation information including a contents ID to identify the contents whose reservation operation is accepted and terminal information to identify the terminal apparatus that accepts the reservation operation to the terminal apparatus determined based on the contents ID, receives the reservation information transmitted from the terminal apparatus that accepts the reservation operation of delivery of the contents and that updates a reservation terminal list that associates the contents ID to identify the contents and the terminal information to identify the terminal apparatus reserved for delivery of the contents based on the received reservation information, verifies whether or not the acquired contents have defects when the contents whose reservation operation is accepted are acquired, transmits a search request having the contents ID to identify the contents judged to have defects to the terminal apparatus determined based on the contents ID to acquire a search result from the terminal apparatus to which the search request is transmitted, receives the search request transmitted from the terminal apparatus judged to have defects in the delivered contents, acquires the terminal information registered correspondingly to the contents ID included in the search request from the reservation terminal list, transmits the acquired terminal information as a search result, and acquires recovery data of the contents judged to have defects from the terminal apparatus identified by the terminal information included in the search result to perform recovery of the contents using the acquired recovery data. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a configuration of a system; 
         FIG. 2  illustrates a hardware configuration of a terminal apparatus; 
         FIG. 3  illustrates the hardware configuration of a delivery apparatus; 
         FIG. 4  illustrates the configuration of a program executed by the terminal apparatus; 
         FIG. 5  illustrates the flow of processing of a system; 
         FIG. 6  illustrates the flow of reservation processing in a request unit PG 100  performed by the terminal apparatus; 
         FIG. 7  illustrates the flow of reservation processing in a management unit PG 200  performed by the terminal apparatus; 
         FIG. 8  illustrates the flow of recording processing in the request unit PG 100  performed by the terminal apparatus; 
         FIG. 9  illustrates the flow of owning candidate search processing in the request unit PG 100  performed by the terminal apparatus; 
         FIG. 10  illustrates the flow of owning candidate search processing in the management unit PG 200  performed by the terminal apparatus; 
         FIG. 11  illustrates an example of a terminal list transmitted from a terminal apparatus C; 
         FIG. 12  illustrates an example of a reservation screen; 
         FIG. 13  illustrates an example of an Electronic Program Guide information table PG 111 ; 
         FIG. 14  illustrates an example of reservation information transmitted from a terminal apparatus A; 
         FIG. 15  illustrates an example of a reservation terminal list held by the terminal apparatus C; 
         FIG. 16  illustrates the data structure of a terminal list PG 110 ; 
         FIG. 17  illustrates the data structure of the Electronic Program Guide information table PG 111 ; 
         FIG. 18  illustrates the data structure of a contents management table PG 112 ; 
         FIG. 19  illustrates the data structure of a reservation list PG 113 ; 
         FIG. 20  illustrates the data structure of a verification information DB (PG 114 ); 
         FIG. 21  illustrates the data structure of a contents DB (PG 115 ); 
         FIG. 22  illustrates the data structure of an owning candidate DB (PG  116 ); 
         FIG. 23  illustrates the data structure of a reservation terminal list PG 210 ; 
         FIG. 24  illustrates the flow of complementary information transmission processing in the management unit PG 200  performed by the terminal apparatus; 
         FIG. 25  illustrates the configuration of a program executed by the terminal apparatus according to a second embodiment; 
         FIG. 26  illustrates the flow of recording processing in the request unit PG 100  according to the second embodiment; 
         FIG. 27  illustrates the configuration of a program executed by the terminal apparatus according to a third embodiment; 
         FIG. 28  illustrates the flow of processing of a system according to the third embodiment; 
         FIG. 29  conceptually illustrates the flow of reservation information shared in a system according to the third embodiment; 
         FIG. 30  illustrates the flow of reservation processing in the management unit PG 200  performed by the terminal apparatus according to the third embodiment; 
         FIG. 31  illustrates the flow of owning candidate search processing in the request unit PG 100  performed by the terminal apparatus according to the third embodiment; 
         FIG. 32  illustrates the configuration of the program executed by the terminal apparatus according to a fourth embodiment; 
         FIG. 33  illustrates the flow of recording processing in the request unit PG 100  according to the fourth embodiment; 
         FIG. 34  illustrates the configuration of the program executed by the terminal apparatus according to a fifth embodiment; 
         FIG. 35  illustrates the flow of owning candidate search processing in the management unit PG 200  performed by the terminal apparatus according to the fifth embodiment; 
         FIG. 36  illustrates the configuration of the program executed by the terminal apparatus according to a sixth embodiment; 
         FIG. 37  illustrates the data structure of a connection result list and an example thereof; 
         FIG. 38  illustrates the data structure of the connection result list and an example (Part 2) thereof; and 
         FIG. 39  illustrates the flow of processing of the system according to the sixth embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     A conventional storage-type service is a service in which contents are delivered by using broadcasting or multicast communication and a user of each node may download contents into a recording medium held by each node to use (view) the downloaded contents at any time the user pleases. 
     In this service, a viewer specifies (reserves) a program to be stored in advance by using Electronic Program Guide (EPG) information. 
     When the delivery time of the specified program comes, the node starts to receive the specified program, which is accumulated in a recording medium accessible from the node. 
     The viewer may view the contents accumulated in the recording medium at any time he (she) pleases. 
     Here, when contents (program data) are delivered, meteorological conditions such as a rainfall and snow may cause a possibility of a loss of a portion of delivered program data at the receiving node in a system that uses radio broadcasting. Further, a network failure or the like may cause a possibility of a loss of a portion of delivered program data not only at the receiving node in a system that uses radio broadcasting but also at the receiving node in a system that uses wire broadcasting. 
     Thus, a system described below distributes recovery data for recovering contents data having different loss locations at each node, using P2P architecture. 
     In order to share information among nodes in a P2P system, each node preferably notifies other nodes participating in the P2P system about owned information. 
     Thus, after contents delivery is completed, a notification of owned contents is issued by respective nodes that have received the contents. 
     If ordinary consumer devices such as broadcasting receivers set up in each home are participating in a P2P system as nodes, the number of nodes in the P2P system will be enormous compared to that of a conventional P2P system. 
     If a notification of owned contents is issued by many nodes that have received the contents after the contents delivery is completed, the communication load increases temporarily in a P2P network leading to a communication failure. 
     After verification processing on delivered contents, a contents search request to search for data to complement defective locations is issued. 
     Also similarly in this case, if a contents search request is issued by many nodes, the communication load increases temporarily in a P2P network leading to a communication failure. 
     Embodiments described below propose a method where terminal apparatuses avoid load concentration when data to perform recovery of defective contents is delivered in a P2P system. 
     According to such terminal apparatuses, load concentration may effectively be avoided when data to perform recovery of defective contents is delivered in a P2P system. 
     First Embodiment 
     [1. System overview]  FIG. 1  illustrates an overview of a system according to the present embodiment. 
     The system illustrated in  FIG. 1  includes a plurality of terminal apparatuses  100 , a delivery apparatus  200 , a communication line  300 , a radio transmitter  400 , and a radio receiver  500 . 
     The Internet, a local area network (LAN), or a wireless LAN (wireless local area network) may be used as the communication line  300 , for example. 
     The terminal apparatus  100  and the terminal apparatus  100 , and the terminal apparatus  100  and the delivery apparatus  200  may perform communication using a protocol such as TCP/IP (Transmission Control Protocol/Internet Protocol) or UDP/IP (User Datagram Protocol/Internet Protocol), or the like via the communication line  300 . 
     The terminal apparatus  100  may receive information transmitted from the delivery apparatus  200  via the radio transmitter  400  and the radio receiver  500 . 
     Also, the terminal apparatus  100  may receive information transmitted from the delivery apparatus  200  via the radio transmitter  400 , the radio receiver  500 , and a set-top box  600  (not shown). 
     As the terminal apparatus  100 , a general-purpose computer, a PDA (Personal Digital Assistant), a mobile phone, and/or a consumer device (for example, a TV set, recording device, refrigerator, and air-conditioner) may be used. 
     [2. Configuration of the terminal apparatus] [2-1. Hardware configuration of the terminal apparatus]  FIG. 2  illustrates the configuration of a terminal apparatus according to the present embodiment. 
     The terminal apparatus illustrated in  FIG. 2  includes a control unit  110 , a storage unit  120 , a communication unit  140 , an operation unit  150 , an output unit  160 , a power supply unit  170 , and a broadcasting receiving unit  180 , and these units are communicably connected via a communication line  130 . 
     The control unit  110  is a unit that realizes given functions according to procedures of programs stored in the storage unit  120 , and is connected to each unit of hardware of the terminal apparatus via the communication line  130 . 
     As the control unit  110 , for example, a CPU (Central Processing Unit), a MPU (Micro Processing Unit), or the like may be used. 
     The storage unit  120  is a unit that stores both a program and data which the control unit executes and refers to. 
     For example, the storage unit  120  includes a main storage unit  121  and an auxiliary storage unit  122 , and reads, into the main storage unit  121 , a program stored in the auxiliary storage unit  122  by processing of the control unit  110  connected via the communication line  130 . 
     The storage unit  120  also transfers data and instruction codes contained in the program read into the main storage unit  121  to the control unit  110 . 
     As the main storage unit  121 , for example, a RAM (Random Access Memory) or ROM (Read Only Memory) may be used. 
     As the auxiliary storage unit  122 , for example, an HDD (Hard Disk Drive), flash memory, or SSD (Solid State Disk) may be used. 
     The communication unit  140  is a unit that transmits and receives a signal to and/or from the terminal apparatus  100  by a wire system or a radio system via the communication line  300 . 
     The operation unit  150  is a unit that receives an operation of the user, and outputs a signal in accordance with the operation of the user to the control unit  110  via the communication line  130 . 
     The operation unit  150 , for example, may include input buttons or a touch panel. 
     The power supply unit  170  is a unit that receives the supply of power necessary for operation of the terminal apparatus  100  and supplies power to each unit via a power supply destination (not shown). 
     The power supply unit  170  also controls the amount of power supplied to each unit via the power supply destination (not shown) in accordance with instructions from the control unit  110  connected via the communication line  130 . 
     In the present embodiment, the power supply unit  170  may be configured to receive the supply of power from an external power supply or from a primary battery or secondary battery mounted in the terminal apparatus  100 . 
     The broadcasting receiving unit  180  is a unit that receives, for example, digital broadcasting, converts the received broadcast signal into a data format that may be processed by the control unit  110 , and supplies the converted data to the control unit  110  via the communication line  130 . 
     The broadcasting receiving unit  180  has a function to separate contents data having dynamic images and sound and Electronic Program Guide information of broadcast programs from a received radio signal of digital broadcasting. 
     The above functions of the broadcasting receiving unit uses conventional technology and thus, a detailed description thereof is omitted. 
     [2-2. Configuration of a program in the terminal apparatus]  FIG. 4  illustrates components of a program executed in a terminal apparatus according to the present embodiment. 
     Components of the program illustrated in  FIG. 4  include a request unit PG 100  and a management unit PG 200 . 
     An overview of each component will be provided below. 
     [2-2-1. Overview of the request unit PG 100 ] As illustrated in  FIG. 4 , the request unit PG 100  includes a participation notification unit PG 101 , a reservation registration unit PG 102 , a reservation transmission unit PG 103 , a broadcasting receiving unit PG 104 , a verification information receiving unit PG 105 , a verification processing unit PG 106 , an owning candidate search unit PG 107 , and a complementary processing unit PG 108 . 
     The control unit  110  operating as a component according to the request unit PG 100  may reference a terminal list PG 110 , an Electronic Program Guide information table PG 111 , a contents management table PG 112 , a reservation list PG 113 , a verification information DB PG 114 , a contents DB PG 115 , and the owning candidate DB PG 116 , and the like. 
     The terminal list PG 110  is stored in the storage unit  120  in a format that allows organization of a plurality of records, each of which is terminal information having a node ID  1101  and address information  1102  (see  FIG. 16 ). 
     The node ID  1101  is information to identify the terminal apparatus  100  in a system according to the present embodiment. 
     The address information  1102  is an address used for communication processing with a terminal apparatus identified by the node ID  1101 . 
     The Electronic Program Guide information table PG 111  is stored in the storage unit  120  in a format that allows organization of a plurality of records, each of which is Electronic Program Guide information having a contents ID  1111  to identify contents and information  1112  indicating the broadcasting date and/or time of the contents (see  FIG. 17 ). 
     The contents management table PG 112  is stored in the storage unit  120  in a format that allows organization of a plurality of records, each of which is contents management information having a contents ID  1121  to identify contents, a divided contents ID  1122  to identify divided contents, and state information  1123  indicating validity of the divided contents (see  FIG. 18 ). 
     The reservation list PG 113  is stored in the storage unit  120  in a format that allows organization of a plurality of records, each of which is reservation information having a contents ID  1131  to identify contents and a broadcasting date and time  1132  (see  FIG. 19 ). 
     The verification information DB PG 114  is stored in the storage unit  120  in a format that allows organization of a plurality of records, each of which is verification information having a contents ID  1141  to identify contents, a divided contents ID  1142  to identify divided contents, and verification data  1143  used for verification processing to judge validity of contents data (see  FIG. 20 ). 
     The contents DB PG 115  is stored in the storage unit  120  in a format that allows organization of a plurality of records, each of which is contents information having a contents ID  1151  to identify contents, a divided contents ID  1152  to identify divided contents, and contents data  1153  made up of images, sound and the like as content of the divided contents (see  FIG. 21 ). 
     The owning candidate DB PG 116  is stored in the storage unit  120  in a format that allows organization of a plurality of records, each of which is owning candidate information having a contents ID  1161  to identify contents and terminal information  1162  indicating information about a terminal apparatus (see  FIG. 22 ). 
     The terminal information may be any information capable of identifying the terminal apparatus in a system according to the present embodiment. 
     As the information about the terminal apparatus, for example, the node ID to identify the terminal apparatus or address information indicating the destination when information is transmitted to the terminal apparatus may be used. 
     Here, as the address information, the IP address, URL, MAC address or the like may be used. 
     The participation notification unit PG 101  is a software component that causes the control unit  110  to operate as a component that transmits a participation notification to notify a system in the present embodiment of the presence of the local terminal, acquires address information of other terminal apparatuses from other terminal apparatuses, and stores the acquired address information in the terminal list PG 110 . 
     The reservation registration unit PG 102  is a software component that causes the control unit  110  to operate as a component that receives a recording reservation of a broadcast program and registers the received reservation details in the reservation list PG 113 . 
     The reservation transmission unit PG 103  is a software component that causes the control unit  110  to operate as a component that transmits the received reservation details to another terminal apparatus connected to the system in the present embodiment. 
     The broadcasting receiving unit PG 104  is a software component that causes the control unit  110  to operate as a component that, based on the reservation details registered in the reservation list PG 113 , receives a broadcast program whose recording reservation is set by using the broadcasting receiving unit  180  and stores contents data supplied from the broadcasting receiving unit  180  in the contents DB PG 115 . 
     The verification information receiving unit PG 105  is a software component that causes the control unit  110  to operate as a component that receives verification information used to verify whether or not there is any error in contents data by using the communication unit  140  or the broadcasting receiving unit  180  and stores the verification information in the verification information DB PG 114 . 
     The verification processing unit PG 106  is a software component that causes the control unit  110  to operate as a component that verifies validity of contents data stored in the contents DB PG 115  using verification information stored in the verification information DB PG 114 . 
     The owning candidate search unit PG 107  is a software component that causes the control unit  110  to operate as a component that searches for the location of a terminal apparatus owning complementary information that complements invalid contents data or incomplete contents data. 
     The complementary processing unit PG 108  is a software component that causes the control unit  110  to operate as a component that transmits a request of complementary information to the terminal apparatus retrieved by the owning candidate search unit PG 107  via the communication unit  140 , receives complementary information transmitted from the terminal apparatus via the communication unit  140 , and updates contents data stored in the contents DB PG 115  using the received complementary information. 
     [2-2-2. Overview of the management unit PG 200 ] As illustrated in  FIG. 4 , the management unit PG 200  includes a participation accepting unit PG 201 , a reservation receiving unit PG 202 , a search processing unit PG 203 , and a complementary information transmission unit PG 204 . 
     The control unit  110  operating as a component according to the management unit PG 200  may also reference the reservation terminal list PG 210 , the terminal list PG 110 , the contents management table PG 112 , and the contents DB PG 115 . 
     A reservation terminal list PG 210  is stored in the storage unit  120  in a format that allows organization of a plurality of records, each of which is reservation terminal information having a contents ID  2101  to identify contents and terminal information  2102  indicating information about a terminal apparatus (see  FIG. 23 ). 
     The terminal apparatus information  2102  may be any information capable of identifying the terminal apparatus in a system according to the present embodiment. 
     As the terminal information, for example, the node ID to identify the terminal apparatus and/or address information indicating the destination when information is transmitted to the terminal apparatus may be used. 
     Here, as the address information, the IP address, URL, MAC address, or the like may be used. 
     The participation accepting unit PG 201  is a software component that causes the control unit  110  to operate as a component that receives a participation notification transmitted from another terminal apparatus connected to a system according to the present embodiment via the communication unit  140  and sends back details of the terminal list PG 110  held in the storage unit  120  via the communication unit  140 . 
     The participation accepting unit PG 201  also is a software component that causes the control unit  110  to operate as a component that, based on information indicated in the received participation notification, registers information about the terminal apparatus that has transmitted the participation notification in the terminal list PG 110  stored in the storage unit  120 . 
     The reservation receiving unit PG 202  is a software component that causes the control unit  110  to operate as a component that receives reservation information transmitted from another terminal apparatus connected to the system according to the present embodiment via the communication unit  140  and updates the reservation terminal list PG 210  based on the received reservation information. 
     That is, the control unit  110  operating as a component according to the reservation receiving unit PG 202  associates the contents ID contained in reservation information received from another terminal apparatus via the communication unit  140  with information about the terminal apparatus that has transmitted the reservation information, and stores the associated information in the reservation terminal list PG 210 . 
     The reservation receiving unit PG 202  is a software component that also causes the control unit  110  to operate as a component that receives reservation information supplied from the request unit PG 100  of the local terminal apparatus and updates the reservation terminal list PG 210  based on the received reservation information. 
     That is, the control unit  110  operating as a component according to the reservation receiving unit PG 202  associates the contents ID contained in reservation information received by using a technique of inter-process communication or the like from the request unit PG 100  executed in the local terminal apparatus with information about the local terminal apparatus, and stores the associated information in the reservation terminal list PG 210 . 
     The search processing unit PG 203  is a software component that causes the control unit  110  to operate as a component that receives a search request transmitted from another terminal apparatus connected to the system according to the present embodiment via the communication unit  140 , references the reservation terminal list PG 210  based on the received search request, and acquires the information  2102  about terminal apparatuses satisfying conditions indicated in the received search request from the reservation terminal list PG 210 . 
     That is, the control unit  110  operating as a component according to the search processing unit PG 203  acquires reservation terminal information corresponding to the contents ID indicated in the search request received via the communication unit  140  from the reservation terminal list PG 210 . 
     The search processing unit PG 203  is a software component that also causes the control unit  110  to operate as a component that generates a terminal list based on the acquired information  2102  about the terminal apparatuses and transmits the generated terminal list to the terminal apparatus that has transmitted the search request via the communication unit  140 . 
     That is, the control unit  110  operating as a component according to the search processing unit PG 203  transmits a terminal list generated based on the terminal information  2102  acquired from the reservation terminal list PG 210  via the communication unit  140 . 
     The search processing unit PG 203  is a software component that also causes the control unit  110  to operate as a component that receives a search request supplied from the request unit PG 100  of the local terminal apparatus and performs search processing based on the received search request and transmission processing of the terminal list. 
     That is, the control unit  110  operating as a component according to the search processing unit PG 203  performs search processing and transmission processing of the terminal list based on the received search request received by using a technique of inter-process communication or the like from the request unit PG 100  executed in the local terminal apparatus. 
     The complementary information transmission unit PG 204  is a software component that causes the control unit  110  to operate as a component that acquires contents data corresponding to the contents ID and divided contents ID indicated in a transmission request of complementary information received from another terminal apparatus connected to the system according to the present embodiment from the contents DB PG 115  held in the storage unit  120 . 
     The complementary information transmission unit PG 204  also is a software component that causes the control unit  110  to operate as a component that transmits complementary information to the terminal apparatus that has transmitted the transmission request. 
     [3. Configuration of the delivery apparatus] [3-1. Hardware configuration of the delivery apparatus]  FIG. 3  illustrates the hardware configuration of the delivery apparatus  200  according to the present embodiment. 
     The delivery apparatus  200  illustrated in  FIG. 3  includes a control unit  210 , a storage unit  220 , a communication unit  240 , an operation unit  250 , an output unit  260 , a power supply unit  270 , and a broadcasting transmitting unit  280 , and these units are communicably connected via a communication line  230 . 
     The control unit  210  is a unit that realizes functions according to procedures of programs stored in the storage unit  220 , and is connected to each unit of hardware of the terminal apparatus via the communication line  230 . 
     As the control unit  210 , for example, a CPU (Central Processing Unit), MPU (Micro Processing Unit), or the like may be used. 
     The broadcasting transmitting unit  280  is a unit that transmits, through the broadcasting transmitting unit  280 , contents data of various programs and verification information to the nodes in the system. 
     The broadcasting transmitting unit  280  is connected to broadcasting equipment  400  that outputs radio waves for broadcasting via a dedicated line or the like. 
     The broadcasting transmitting unit  280  may also be connected to a communication line  300  such as the Internet to transmit contents data of various programs and verification information via the communication line  300  such as the Internet. 
     Other components of the hardware configuration of the delivery apparatus  200  are the same as those of a general personal computer or the like and thus, a detailed description thereof is omitted. 
     [4. Flow of processing of the overall system]  FIG. 5  illustrates the processing flow of a system according to the present embodiment. 
     The example in  FIG. 5  illustrates the flow of processing when a terminal apparatus A ( 100 ) participates in a system according to the present embodiment and the terminal apparatus A ( 100 ) receives contents from the system according to the present embodiment. 
     [4-1. Participation in a P2P system] First, the terminal apparatus A transmits a participation notification to notify the presence of the local terminal in a system to other terminal apparatuses connected to the system (S 100  and S 100 ′). 
     That is, the control unit  110  operating as a component according to the participation notification unit PG 101  held by the request unit PG 100  illustrated in  FIG. 4  outputs a signal indicating a participation notification to the communication line  300  using the communication unit  140 . 
     For example, the terminal apparatus A transmits a signal indicating a participation notification to an indefinite number of terminal apparatuses communicably connected via the communication line  300 . 
     Here, broadcast technology, multicast technology, and the like may be used in an IP network (Internet Protocol Network) for transmission processing of a signal to an indefinite number of terminal apparatuses. 
     A terminal apparatus B and a terminal apparatus C that receive the signal indicating a participation notification from the terminal apparatus A transmit the terminal list (PG 110 ) stored in the storage unit  120  held by the terminal apparatus B and C to the terminal apparatus A (S 101  and S 101 ′). 
     That is, with the control unit  110  operating as a component according to the participation accepting unit PG 201  held by the management unit PG 200  illustrated in  FIG. 4 , if a received message acquired from the communication unit  140  via the communication line  130  is a signal indicating a participation notification, the control unit  110  transmits details registered in the terminal list PG 110  stored in the storage unit  120  to the terminal apparatus that has transmitted the participation notification. 
     When a terminal list stored in the storage unit  120  is transmitted, each terminal apparatus may transmit information on the local terminal apparatus with the terminal list. 
     Each terminal apparatus may also store information about the local terminal apparatus in the terminal list stored in the storage unit  120 , in addition to the addition thereof to the terminal list. 
       FIG. 11  illustrates an example of a terminal list transmitted from the terminal apparatus C. 
     The terminal list illustrated in  FIG. 11  includes the node ID  1101  indicating information for identifying the terminal apparatus in a P2P system and the address information  1102  used as information for identifying the transmission destination or transmission source terminal apparatus when communication is performed via the communication line  300 . 
     The example in  FIG. 11  illustrates that the terminal apparatus C participates in the system according to the present embodiment before the participation notification is received from the terminal apparatus A and has acquired the node ID and address information of the terminal apparatus B that similarly participates in the system. 
     Here, the node ID may be any information capable of identifying each of the terminal apparatuses  100  in the system according to the present embodiment. 
     For example, a hash value obtained by hashing a serial number, machine name, or the like assigned in advance when shipped from a factory by using a common hash function may be used as the node ID. 
     By using the hash value as information to identify the terminal apparatus in the system according to the present embodiment, terminal apparatuses participating in the system according to the present embodiment may be managed based on the magnitude or the like of the hash value. 
     For example, by using a hash function whose number of generating digits is 128 bits, as many as about 340×10̂36 terminal apparatus, which is the 128-th power of 2, may be managed in the system according to the present embodiment. 
     The terminal apparatus A aggregates terminal lists received from each terminal apparatus and stores the aggregated terminal list in the storage unit  120 . 
     That is, with the control unit  110  operating as a component according to the participation notification unit PG 101  held by the request unit PG 100  illustrated in  FIG. 4 , the control unit  110  aggregates terminal lists received from each terminal apparatus and registers the aggregated terminal list in the terminal list PG 110  held in the storage unit  120 . 
     [4-2. Reservation processing] Next, when an instruction to make a reservation to receive delivery of contents by an input operation of the operator is received, the terminal apparatus A stores reservation details in the storage unit  120  and transmits reservation information indicating the reservation details to the management node identified based on the reserved contents (S 102 ). 
     That is, with the control unit  110  operating as a component according to the reservation registration unit PG 102  held by the request unit PG 100  illustrated in  FIG. 4 , the control unit  110  registers reservation details in the reservation list PG 113  held by the storage unit  120 . 
     Also, with the control unit  110  operating as a component according to the reservation transmission unit PG 103  held by the request unit PG 100 , the control unit  110  transmits reservation information via the communication unit  140 . 
       FIG. 12  illustrates an example of a reservation screen that displays a reservation operation in the terminal apparatus. 
     In a reservation screen  1200  illustrated in  FIG. 12 , a contents delivery schedule table  1210  including a time  1201  which indicates starting time of contents, a delivery station AAA  1202 , a delivery station BBB  1203 , and a delivery station CCC  1204  are displayed. The delivery station MA  1202 , the delivery station BBB  1203 , and the delivery station CCC  1204  illustrated in  FIG. 12  are examples of broadcast stations which broadcast contents. 
     In the example illustrated in  FIG. 12 , the operator of the terminal apparatus may input a reservation instruction of desired contents A- 4  into the terminal apparatus by selecting the contents A- 4  ( 1211 ) indicated in the reservation screen  1200  and pressing a reservation button  1212 . 
       FIG. 14  illustrates an example of the reservation information transmitted from the terminal apparatus A. 
     The reservation information illustrated in  FIG. 14  includes a contents ID  1401  and address information  1402 . 
     The contents ID  1401  may be any information capable of identifying contents in a system according to the present embodiment. 
     For example, a hash value obtained by hashing information such as the name given to the contents by a delivery station of the contents and data length of the contents by using a common hash function may be used as the contents ID. 
     The address information  1402  is information indicating the address of the terminal apparatus that transmits the reservation information and, for example, the IP address, URL, or MAC address may be used as the address information  1402 . 
     In the example illustrated in  FIG. 14 , information identifying the contents A- 4  is illustrated as the contents ID  1401  and information indicating the address of the terminal apparatus A is illustrated as the address information  1402 . 
     When the system according to the present embodiment uses the hash value in order to identify contents in the system according to the present embodiment, the system may efficiently manage a lot of contents by using the magnitude of the hash value. 
     Further, when the system uses the hash value in order to identify contents and to identify the terminal apparatus in the system, the magnitude of the hash value as a contents ID and that of the hash value as a terminal apparatus ID may be compared. 
     In the example illustrated in  FIG. 5 , the terminal apparatus A transmits reservation information indicating details of the reservation instruction to the terminal apparatus C as the management node determined based on the contents whose reservation instruction is accepted (S 102 ). 
     For example, by comparing the magnitude of the contents ID of contents whose reservation instruction is accepted and that of the terminal ID registered in the terminal list, the terminal apparatus whose contents ID and terminal ID are nearest (the difference is the smallest value) may be determined as the management node. 
     When, instead of the hash value, character type data in which alphabetical characters and symbols are mixed is used as the contents ID and terminal ID, the magnitude thereof may be compared by using a character code such as ASCII (American Standard Code for Information Interchange) and/or Unicode. 
     The terminal apparatus C updates the reservation terminal list stored in the storage unit  120  based on reservation information received from the terminal apparatus A. 
       FIG. 15  illustrates an example of the reservation terminal list stored in the terminal apparatus C. 
     The reservation terminal list illustrated in  FIG. 15  includes a contents ID  1501  and address information  1502 . 
     The contents ID  1501  is registered based on the contents ID  1401  contained in the received reservation information. 
     The address information  1502  is registered based on the address information  1402  contained in the received reservation information. 
     The example in  FIG. 15  illustrates that information to identify the contents A- 4  is registered as the contents ID  1501 , and an address  1  of the terminal apparatus A and an address  2  of the terminal apparatus B are registered as information indicating addresses of terminal apparatuses that have transmitted reservation information for the contents A- 4 . 
     [4-3. Delivery processing] Next, the terminal apparatus A receives contents whose reservation instruction is accepted from the delivery apparatus  200  and stores the received contents data in the contents DB PG 115  by associating with the contents ID with the divided contents ID (S 103 ). 
     That is, with the control unit  110  operating as a component according to the broadcasting receiving unit PG 104  held by the request unit PG 100  illustrated in  FIG. 4 , the control unit  110  registers contents received via the communication unit  140  in the contents DB PG 115  held in the storage unit  120 . 
     The trigger for performing reception processing of contents data may be linked, for example, to the arrival of the time when contents whose reservation instruction is accepted is delivered from the delivery apparatus. 
     In this case, the terminal apparatus may acquire the delivery time to be linked from Electronic Program Guide information. 
     Further, the terminal apparatus A receives verification information of contents whose reservation instruction is accepted from the delivery apparatus  200  and stores the received verification information in the verification information DB PG 114  by associating the contents ID with the divided contents ID (S 104 ). 
     That is, with the control unit  110  operating as a component according to the verification information receiving unit PG 105  held by the request unit PG 100 , the control unit  110  registers verification information received via the communication unit  140  in the verification information DB PG 114  held in the storage unit  120 . 
     It is not always necessary to link the trigger for performing reception processing of verification information with the above delivery time. 
     For example, the terminal apparatus receives verification information repeatedly transmitted by associating the contents ID with the divided contents ID by a data carousel transmission method at an appropriate timing. 
     That is, the terminal apparatus may receive verification information together with contents data or before or after receiving contents data. 
     In the example illustrated in  FIG. 5 , the reception processing of contents data and verification information are performed also by the terminal apparatus B (S 103 ′ and S 104 ′). 
     That is, the contents DB PG 115  held by the terminal apparatus B has contents data having the same contents ID as that of the contents received by the terminal apparatus A in the above processing S 103  stored therein. 
     However, the terminal apparatus A and the terminal apparatus B may have different content of contents data stored in the contents DB PG 115 . 
     This may occur if the weather is different at the installation locations of both terminal apparatuses when, for example, the weather in a region where the terminal apparatus A is installed is torrential rain during reception while the weather in a region where the terminal apparatus B is installed is fine weather during reception. 
     That is, if the weather of a region where a terminal apparatus is installed is torrential rain, reception sensitivity deteriorates due to rain attenuation and, as a result, content of contents data may become incomplete or an erroneous value may arise in the data. 
     In addition to the weather, noise may be entrapped due to a malfunction of equipment of the terminal apparatus, resulting in content of contents data which is different from original values. 
     [4-4. Verification processing] Next, the terminal apparatus A performs verification processing of the contents data stored in the contents DB PG 115  using the received verification information. 
     That is, the control unit  110  operating as the verification processing unit PG 106  held by the request unit PG 100  illustrated in  FIG. 4  performs verification processing of the contents registered in the contents DB PG 115  held in the storage unit  120  using verification information registered in the verification information DB PG 114  held in the storage unit  120 . 
     The terminal apparatus A performs processing to acquire complementary information for locations judged not to be appropriate as a result of performing search processing. 
     First, the terminal apparatus A transmits a search request to obtain the location of a terminal apparatus owning complementary information for applicable locations to the terminal apparatus C operating as the management node (S 105 ). 
     That is, the control unit  110  operating as the owning candidate search unit PG 107  held by the request unit PG 100  illustrated in  FIG. 4  transmits a signal indicating a search request via the communication unit  140 . 
     Here, the search request transmitted from the terminal apparatus A has the contents ID of contents judged not to be appropriate in the above verification. 
     The terminal apparatus C acquires reservation terminal information corresponding to the contents ID indicated in the received search request from the reservation terminal list PG 210 . 
     The terminal apparatus C transmits a terminal list generated based on the acquired reservation terminal information to the terminal apparatus A that has transmitted the search request (S 106 ). 
     That is, the control unit  110  operating as the search processing unit PG 203  held by the management unit PG 200  illustrated in  FIG. 4  acquires reservation terminal information registered in the reservation terminal list PG 210  held in the storage unit  120  and transmits the acquired reservation terminal information via the communication unit  140 . 
     The terminal apparatus A transmits an acquisition request to acquire complementary information of contents to the terminal apparatus indicated in the received terminal list (S 107 ). 
     That is, the control unit  110  operating as the complementary processing unit PG 108  held by the request unit PG 100  illustrated in  FIG. 4  transmits a signal indicating an acquisition request via the communication unit  140 . 
     Here, the acquisition request transmitted from the terminal apparatus A has the contents ID to identify contents and divided contents ID. 
     The terminal apparatus B acquires divided contents data corresponding to the contents ID and divided contents ID indicated in the received acquisition request from the contents DB PG 115 . 
     The terminal apparatus B transmits the acquired divided contents data to the terminal apparatus A that has transmitted the acquisition request as complementary information (S 108 ). 
     That is, the control unit  110  operating as the complementary information transmission unit PG 204  held by the management unit PG 200  illustrated in  FIG. 4  acquires complementary information by referencing the contents DB PG 115  held in the storage unit  120  and transmits the acquired complementary information via the communication unit  140 . 
     Here, complementary information transmitted from the terminal apparatus B has the contents ID to identify contents, divided contents ID, and divided contents data. 
     The terminal apparatus A updates divided contents data stored in the contents DB PG 115  by associating the contents ID with the divided contents ID indicated in the received complementary information using the divided contents data included in the received complementary information. 
     The foregoing is the flow of overall processing of a system according to the present embodiment. 
     [5. Flow of reservation processing in the request unit PG 100 ] Next, a procedure for reservation processing in the request unit PG 100  performed by the terminal apparatus  100  will be described using  FIG. 6 . 
       FIG. 6  illustrates a processing procedure for reservation processing in the request unit PG 100  performed by the terminal apparatus. 
     The processing procedure illustrated in  FIG. 6  is performed by the control unit  110  operating as the reservation registration unit PG 102  or the reservation transmission unit PG 103  held by the request unit PG 100  illustrated in  FIG. 4 . 
     First, the control unit  110  of the terminal apparatus acquires the current date and time from a system clock (not shown) or the like (S 201 ) and sets the display range of Electronic Program Guide based on the acquired date and time (S 202 ). 
     Here, a range of time starting from the acquired date/time may be set as the display range. 
     For example, if the current date and time is “Oct. 13, 2008, 10:00” and the range of time is “three hours”, the start point of the display range is “Oct. 13, 2008, 10:00” and the end point of the display range is “Oct. 13, 2008, 13:00”. 
     Next, the control unit  110  references the Electronic Program Guide information table PG 111  to acquire Electronic Program Guide information corresponding to the display range set in the above processing S 202  (S 203 ) and displays an Electronic Program Guide screen based on the acquired Electronic Program Guide information (S 204 ). 
       FIG. 13  illustrates an example of the Electronic Program Guide information table PG 111 . 
     Electronic Program Guide information stored in the Electronic Program Guide information table PG 111  illustrated in  FIG. 13  has a delivery station ID  1301 , a contents ID  1302 , a start date/time  1303 , and an end date/time  1304 . 
     The control unit  110  references the start date/time  1303  and the end date/time  1304  included in the Electronic Program Guide information stored in the Electronic Program Guide information table PG 111  in the above processing S 203  to compare the time zone indicated by the start date/time  1303  and the end date/time  1304  and the display range set in the above processing S 202 . 
     If, as a result of comparison, the time zone indicated by the start date/time  1303  and the end date/time  1304  and the display range set in the above processing S 202  overlap at least partially, the control unit  110  judges that the display range is applicable. 
     In the example illustrated in  FIG. 13 , if the display range is set with the start point “Oct. 13, 2008, 10:00” and the end point “Oct. 13, 2008, 13:00”, Electronic Program Guide information applicable to the display range includes Electronic Program Guide information A 1301  to A 1304 , Electronic Program Guide information B 1301  to B 1306 , and Electronic Program Guide information C 1301  to C 1304 . 
     That is, as illustrated in  FIG. 13 , Electronic Program Guide information A 1300 , Electronic Program Guide information B 1300 , and Electronic Program Guide information C 1300  have no overlap with the time zone set as the display range and are judged not to be applicable to the display range and excluded from acquisition targets in the above processing S 203 . 
       FIG. 12  illustrates an example of an Electronic Program Guide screen displayed in the terminal apparatus. 
     The Electronic Program Guide screen illustrated in  FIG. 12  displays the Electronic Program Guide list  1210  including the time  1201 , the delivery station AAA ( 1202 ), the delivery station BBB ( 1203 ), and the delivery station CCC ( 1204 ), a display range notification field  1205 , display range change instruction units  1206  to  1209 , a program selection unit  1211 , and the reservation instruction unit  1212 . 
     The display range notification field  1205  illustrated in  FIG. 12  indicates that the display range of the Electronic Program Guide information displayed in the Electronic Program Guide list  1210  is “Oct. 13, 2008, 10:00” as the start point and “Oct. 13, 2008, 12:30” as the end point. 
     The Electronic Program Guide list  1210  illustrated in  FIG. 12  indicates that “Contents A- 1 ” is delivered in the time zone “10:00 to 10:30”, “Contents A- 2 ” in the time zone “10:30 to 11:00”, “Contents A- 3 ” in the time zone “11:00 to 12:00”, and “Contents A- 4 ” in the time zone “12:00 to 13:00” as programs delivered by the delivery station AAA ( 1202 ). 
     In the Electronic Program Guide list  1210  illustrated in  FIG. 12 , the delivery station BBB ( 1203 ) and the delivery station CCC ( 1204 ) are similar to the delivery station AAA ( 1202 ) and thus, a description thereof is omitted. 
     If a detection signal indicating that an input operation has been performed in the Electronic Program Guide screen is received from the operation unit  150 , the control unit  110  judges whether or not the input operation is a press of the reservation instruction unit  1212  (S 205 ). 
     If the control unit  110  judges that the input operation is a press of the reservation instruction unit  1212  in the above judgment processing at S 205  (YES at S 205 ), the control unit  110  performs registration processing of reservation information (S 206 ). 
     That is, the control unit  110  acquires Electronic Program Guide information indicating a program selected by the program selection unit  1211 , generates reservation information based on the acquired Electronic Program Guide information, and registers the reservation information in the reservation list PG 113  (S 206 ). 
     The example illustrated in  FIG. 12  indicates that the program selection unit  1211  has selected the program “contents A- 4 ” of “delivery station AAA”. 
     The control unit  110  generates reservation information having the contents ID  1302  indicated in the Electronic Program Guide information and registers the reservation information in the reservation list PG 113 . 
     At this point, the broadcasting date/time  1112  (the start date/time  1303  and the end date/time  1304 ) acquired from the Electronic Program Guide information may be registered as reservation information, or the broadcasting date/time  1112  (the start date/time  1303  and the end date/time  1304 ) may be acquired from the Electronic Program Guide information each time reservation information is referenced. 
     Next, the control unit  110  decides the terminal apparatus to be set as a transmission destination of reservation information based on the contents ID indicated in the Electronic Program Guide information acquired in the above processing S 206  (S 207 ). 
     The control unit  110  compares the contents ID  1302  indicated in the Electronic Program Guide information acquired in the above processing S 206  and the node ID  1101  registered in the terminal list PG 110  to acquire the node ID  1101  having the value nearest to the value of the contents ID  1302 . 
     The control unit  110  acquires the address information  1102  corresponding to the acquired node ID from the terminal list PG 110  (S 207 ). 
     The control unit  110  uses the address of the terminal apparatus  100  indicated in the acquired address information  1102  to transmit the contents ID acquired from the Electronic Program Guide information table PG 111  in the above processing S 206  and the reservation information having address information or node ID allocated to the local terminal apparatus (S 208 ). 
     The control unit  110  may also use the technique of inter-process communication or the like to transmit reservation information to the management unit PG 200  performed by the local terminal apparatus (S 208 ). 
     If, on the other hand, the control unit  110  judges that the input operation is not a press of the reservation instruction unit  1212  in the above judgment processing at S 205  (NO at S 205 ), the control unit  110  judges whether the input operation is a press of the display range change instruction units  1206  to  1209  indicating a change instruction of the display range (S 209 ). 
     In the example illustrated in  FIG. 12 , the display range change instruction unit  1206  is used to input an instruction to move the display range backward by, for example, one day, the display range change instruction unit  1207  to input an instruction to move the display range backward by, for example, one hour, the display range change instruction unit  1208  to input an instruction to move the display range forward by, for example, one hour, and the display range change instruction unit  1209  to input an instruction to move the display range forward by, for example, one day. 
     If the control unit  110  judges that the input operation is a press of the display range change instruction units  1206  to  1209  indicating a change instruction of the display range (YES at S 209 ), the control unit  110  updates the display range depending on which display range change instruction unit  1206  to  1209  is pressed (S 210 ). 
     If, on the other hand, the control unit  110  judges that the input operation is not a press of the display range change instruction units  1206  to  1209  indicating a change instruction of the display range (NO at S 209 ), the control unit  110  performs processing of the above processing S 205  and thereafter. 
     The foregoing is the flow of reservation processing by the request unit PG 100  performed by a terminal apparatus according to the present embodiment. 
     [6. Flow of reservation processing in the management unit PG 200 ] Next, a procedure for reservation processing in the management unit PG 200  performed by a terminal apparatus will be described using  FIG. 7 . 
       FIG. 7  is a diagram illustrating a procedure for reservation processing in the management unit PG 200  performed by the terminal apparatus. 
     The processing procedure illustrated in  FIG. 7  is performed by the control unit  110  operating as the reservation receiving unit PG 202  held by the management unit PG 200  illustrated in  FIG. 4 . 
     First, the control unit  110  of the terminal apparatus judges whether reception of reservation information is detected (S 300 ). 
     If the control unit  110  analyzes a received message acquired from the communication unit  140  via the communication line  130  and judges that the received message indicates reservation information, the control unit  110  judges that reception of reservation information is detected (YES at S 300 ). 
     If the control unit  110  analyzes a received message acquired from the request unit PG 100  performed by the local terminal apparatus using the technique of inter-process communication or the like and judges that the received message indicates reservation information, the control unit  110  may also judge that reception of reservation information is detected (YES at S 300 ). 
     If reception of reservation information is detected (YES at S 300 ), the control unit  110  acquires the received reservation information from the communication unit  140  and registers reservation terminal information in the reservation terminal list PG 210  based on the acquired reservation information (S 301 ). 
     That is, the control unit  110  registers reservation terminal information having the contents ID  2101  and the terminal information  2102  in the reservation terminal list PG 210  based on the contents ID and terminal information indicated in the reservation information. 
     Here, the terminal information  2102  may be a node ID or address information. 
     The control unit  110  performs the above processing S 300  after performing registration processing of the reservation terminal information. 
     If the control unit  110  judges in the above processing S 300  that reception of reservation information is not detected (NO at S 300 ), the control unit  110  performs the processing S 300  again after a certain time has passed. 
     The foregoing is the flow of reservation processing in the management unit PG 200  performed by the terminal apparatus  100  according to the present embodiment. 
     [7. Recording processing in the request unit PG 100 ] Next, a procedure for recording processing in the request unit PG 100  performed by the terminal apparatus  100  will be described using  FIG. 8 . 
       FIG. 8  illustrates the flow of recording processing in the request unit PG 100  performed by the terminal apparatus  100 . 
     The processing procedure illustrated in  FIG. 8  is performed by the control unit  110  functioning as the broadcasting receiving unit PG 104 , the verification information receiving unit PG 105 , the verification processing unit PG 106 , the owning candidate search unit PG 107 , the complementary processing unit PG 108 , or the like held by the request unit PG 100  illustrated in  FIG. 4 . 
     First, the control unit  110  of the terminal apparatus judges whether verification information is received (S 400 ). 
     If the control unit  110  analyzes a received message acquired from the communication unit  140  via the communication line  130  and judges that the received message indicates verification information, the control unit  110  judges that verification information is received (YES at S 400 ). 
     If the control unit  110  judges that verification information is received (YES at S 400 ), the control unit  110  registers the received verification information in the verification information DB PG 114 . 
     As illustrated in  FIG. 20 , the verification information includes the contents ID  1141 , the divided contents ID  1142 , and verification data  1143 . 
     As the verification data, for example, a hash value obtained by hashing contents data divided into certain time units may be used. 
     If the control unit  110  judges in the above processing S 400  that no verification information is received (NO at S 400 ), the control unit  110  judges whether or not contents are received (S 402 ). 
     If the control unit  110  analyzes a received message acquired from the communication unit  140  via the communication line  130  and judges that the received message indicates contents information, the control unit  110  judges that contents are received (YES at S 402 ). 
     If the control unit  110  judges that contents information is received (YES at S 402 ), the control unit  110  registers the received contents information in the contents DB PG 115  and contents management information indicating a state of the received contents information in the contents management table (PG 112 ) (S 403 ). 
     As illustrated in  FIG. 21 , the contents information includes the contents ID  1151 , the divided contents ID  1152 , and the contents data  1153 . 
     The contents data  1153  is contents data obtained by dividing contents identified by the contents ID  1151  into predetermined time units or the like. 
     As illustrated in  FIG. 18 , the contents management information includes the contents ID  1121 , the divided contents ID  1122 , and the state information  1123 . 
     The state information  1123  indicates a result of verification processing performed on contents data included in the contents information. 
     The state information  1123  has, for example, a value indicating “not verified” before verification processing being performed stored therein. 
     If, as a result of performing verification processing, consistency with the verification information is found, a value indicating “consistent” is stored, and if no consistency with the verification information is found, a value indicating “not consistent” is stored. 
     Contents information received by the radio receiver  500  may not have the divided contents ID. 
     In this case, contents data included in contents information received by the radio receiver  500  may be reconfigured into units for verification processing with the sequence number indicating the reconfigured order attached by the terminal apparatus  100 . 
     That is, in this example, the above sequence number may be used as the divided contents ID included in contents information and verification information. 
     Next, the control unit  110  acquires verification information corresponding to the contents ID and divided contents ID included in the contents information registered in the contents DB PG 115  in the above processing S 403  from the verification information DB PG 114  (S 404 ). 
     The control unit  110  uses the verification data  1143  included in the acquired verification information to perform verification processing of consistency of contents data included in the contents information. 
     The control unit  110  compares, for example, a hash value generated from the contents data using the same algorithm as that used for generating verification data with the verification data and if both values match, the control unit  110  may judge that the contents data is consistent (No at S 406 ). 
     That is, if the control unit  110  judges that the contents data is not defective (NO at S 406 ), the control unit  110  performs processing in the above processing S 400  and thereafter. 
     On the other hand, if, as a result of performing the above processing S 405 , the control unit  110  judges that the contents data is defective (YES at S 406 ), the control unit  110  searches for an owning candidate indicating a terminal apparatus that may have data to complement the defects (S 407 ). 
     An example of search processing in the processing S 407  will be described later. 
     The control unit  110  judges, as a result of performing search processing, whether or not an owning candidate is found (S 408 ) 
     If, as a result of performing the above search processing, the control unit  110  judges that an owning candidate is obtained (YES at S 408 ), the control unit  110  transmits an acquisition request to request transmission of complementary information to the terminal apparatus indicated by an owning candidate acquired by the above search processing (S 409 ). 
     Here, the acquisition request transmitted to the terminal apparatus indicated by an owning candidate includes the contents ID and divided contents ID corresponding to the contents data judged to be defective in the above verification processing. 
     Data organized in a list form indicating a plurality of terminal apparatuses may be used as owning candidates acquired in the above search processing (S 407 ). 
     In this case, the control unit  110  may select terminal apparatuses indicated in the owning candidate list in any order to sequentially transmit an acquisition request to these terminal apparatuses, or multicasting may be used (S 409 ). 
     On the other hand, if the control unit  110  judges in the above processing S 408  that acquisition of an owning candidate failed (NO at S 408 ), the control unit  110  transmits an acquisition request to request transmission of complementary information to the delivery apparatus  200  (S 412 ). 
     Here, the acquisition request transmitted to the delivery apparatus  200  includes the contents ID and divided contents ID corresponding to the contents data judged to be defective in the above verification processing. 
     The control unit  110  receives complementary information from the transmission destination of the acquisition request (S 410 ) and performs complementary processing using the received complementary information (S 411 ). 
     Here, the complementary information received from the transmission destination of the acquisition request includes the contents ID, divided contents ID, and the contents data. 
     That is, in the above complementary processing, the control unit  110  searches the contents DB PG 115  for contents information corresponding to the contents ID and divided contents ID in the received complementary information. 
     Then, the control unit  110  updates contents data included in the searched contents information by using contents data included in the received complementary information. 
     If the transmission destination of the acquisition request does not own consistent contents data, the control unit  110  receives incomplete complementary information in the above processing S 410 . 
     In this case, the control unit  110  discards the complementary information without performing the above processing S 411  and may perform reception processing of complementary information from the terminal apparatus of another owning candidate or from the delivery apparatus. 
     The foregoing is the flow of recording processing in the request unit PG 100  performed by the terminal apparatus  100 . 
     In the above example, recording processing using the terminal apparatus  100  is described and the above complementary processing may be performed when delivered contents are reproduced. 
     [8. Owning candidate search processing in the request unit PG 100 ] Next, a procedure for owning candidate search processing performed in the above processing S 407  will be described using  FIG. 9 . 
       FIG. 9  illustrates the flow of owning candidate search processing in the request unit PG 100  performed by the terminal apparatus. 
     The processing procedure illustrated in  FIG. 9  is performed by the control unit  110  operating as an owning candidate search unit PG 107  held by the request unit PG 100  illustrated in  FIG. 4 . 
     First, the control unit  110  starts owning candidate search processing by specifying the contents ID. In step S 500  of owning candidate search processing, the control unit  110  acquire the specified contents ID (S 500 ). 
     Here, the contents ID is the contents ID corresponding to the contents data judged to be defective by the verification processing performed in the above processing S 405 . 
     The control unit  110  judges whether or not owning candidate information is present (S 501 ). 
     If, for example, the control unit  110  has acquired owning candidate information from the management unit PG 200  performed by the local terminal apparatus or another terminal apparatus, the control unit  110  judges that owning candidate information is present (NO at S 501 ). 
     If the control unit  110  judges in the above processing S 501  that an owning candidate is present (NO at S 501 ), the control unit  110  outputs owning candidate information already held as a search result (S 506 ). 
     On the other hand, if the control unit  110  judges in the above processing S 501  that an owning candidate is not present (YES at S 501 ), the control unit  110  performs selection processing of the management node (S 502 ). 
     For example, the control unit  110  compares the contents ID acquired in the above processing S 500  and the node ID  1101  registered in the terminal list PG 110  to select the node ID  1101  having the value nearest to that of the contents ID. 
     The control unit  110  acquires the address information  1102  corresponding to the acquired node ID from the terminal list PG 110  (S 502 ). 
     The control unit  110  transmits a search request containing the contents ID acquired in the above processing S 500  to the terminal apparatus indicated in the acquired address information  1102  (S 503 ). 
     The control unit  110  may also transmit a search request to the management unit PG 200  performed by the local terminal apparatus by using a technique such as inter-process communication (S 503 ). 
     The control unit  110  receives a terminal list as a search result from the transmission destination of the search request (S 504 ) and registers the received terminal list in the owning candidate DB PG 116  (S 505 ). 
     The terminal list received in the above processing S 504  includes the contents ID and terminal information. 
     The terminal information may be a node ID or address information. 
     If the node ID is used as the terminal information, the address information  1102  may be acquired by referencing the terminal list PG 110 . 
     The control unit  110  outputs the terminal list received in the above processing S 504  as a list of owning candidates (S 506 ). 
     The foregoing is the flow of search processing in the request unit PG 100  performed by the terminal apparatus  100  according to the present embodiment. 
     [9. Owning candidate search processing in the management unit PG 200 ] Next, a procedure for owning candidate search processing performed by the terminal apparatus  100  that receives a search request transmitted in the above processing S 503  will be described using  FIG. 10 . 
       FIG. 10  illustrates the flow of owning candidate search processing in the management unit PG 200  performed by the terminal apparatus. 
     The processing procedure illustrated in  FIG. 10  is performed by the control unit  110  operating as the search processing unit PG 203  or the like held by the management unit PG 200  illustrated in  FIG. 4 . 
     First, the control unit  110  judges whether a search request is received (S 600 ). 
     If the control unit  110  analyzes a received message acquired from the communication unit  140  via the communication line  130  and judges that the received message indicates a search request, the control unit  110  judges that a search request is received (YES at S 600 ). 
     If the control unit  110  analyzes a received message acquired from the request unit PG 100  performed by the local terminal apparatus using the technique of inter-process communication or the like and judges that the received message indicates a search request, the control unit  110  may also judge that a search request is received (YES at S 600 ). 
     If the control unit  110  judges that a search request is received (YES at S 600 ), the control unit  110  performs search processing of the reservation terminal (S 601 ). 
     That is, the control unit  110  references the reservation terminal list PG 210  to acquire the terminal information  2102  corresponding to the contents ID indicated by the received search request (S 601 ). 
     The terminal information may be a node ID or address information. 
     If the node ID is used as the terminal information, the address information  1102  may be acquired by referencing the terminal list PG 110 . 
     The control unit  110  generates a terminal list, which is a search result, based on the terminal information  2102  acquired in the above processing S 601  (S 602 ) and transmits the generated terminal list to the request unit PG 100  of the terminal apparatus that has transmitted the search request (S 603 ). 
     The foregoing is the flow of owning candidate search processing in the management unit PG 200  performed by the terminal apparatus  100  according to the present embodiment. 
     [10. Complementary information transmission processing in the management unit PG 200 ] Next, a procedure for complementary information transmission processing performed by the terminal apparatus  100  that receives an acquisition request transmitted in the above processing S 409  will be described using  FIG. 24 . 
       FIG. 24  illustrates the flow of complementary information transmission processing in the management unit PG 200  performed by the terminal apparatus  100 . 
     The processing procedure illustrated in  FIG. 24  is performed by the control unit  110  operating as the complementary information transmission unit PG 204  or the like held by the management unit PG 200  illustrated in  FIG. 4 . 
     First, the control unit  110  judges whether a transmission request of complementary information is received (S 2501 ). 
     If the control unit  110  analyzes a received message acquired from the communication unit  140  via the communication line  130  and judges that the received message indicates a transmission request of the complementary information, the control unit  110  judges that a transmission request is received (YES at S 2501 ). 
     If the control unit  110  analyzes a received message acquired from the request unit PG 100  performed by the local terminal apparatus using the technique of inter-process communication or the like, and judges that the received message indicates a transmission request of the complementary information, the control unit  110  may also judge that a transmission request of the complementary information is received (YES at S 2501 ). 
     If the control unit  110  judges that a transmission request is received (YES at S 2501 ), the control unit  110  performs search processing of the contents management table PG 112  (S 2502 ). 
     That is, the control unit  110  acquires contents management information corresponding to the contents ID and divided contents ID indicated in the received transmission request from the contents management table PG 112  (S 2502 ). 
     The control unit  110  references the state information  1123  included in the acquired contents management information to judge whether a value indicating consistency is set (S 2503 ). 
     If the control unit  110  judges that a value indicating consistency is set to the state information  1123  (YES at S 2503 ), the control unit  110  performs search processing of the contents DB PG 115  (S 2504 ). 
     That is, the control unit  110  acquires contents data corresponding to the contents ID and divided contents ID indicated in the transmission request received in the above processing S 2501  from the contents DB PG 115  (S 2504 ). 
     The control unit  110  generates complementary information having the acquired contents data and transmits the generated complementary information to the terminal apparatus that has transmitted the transmission request (S 2505 ). 
     On the other hand, if the control unit  110  judges in the above processing S 2503  that no value indicating consistency is set to the state information  1123  (NO at S 2503 ), the control unit  110  transmits complementary information indicating that no consistent contents data is owned (S 2506 ). 
     That is, the control unit  110  transmits incomplete complementary information having no contents data corresponding to the contents ID and divided contents ID indicated in the transmission request received in the above processing S 2501 . 
     The foregoing is the flow of complementary information transmission processing in the management unit PG 200  performed by the terminal apparatus  100 . 
     Second Embodiment 
     [1. Configuration of a program executed by the terminal apparatus according to the second embodiment]  FIG. 25  illustrates the configuration of a program executed by the terminal apparatus according to the present embodiment. 
     The same reference numerals are attached to the same components of the program illustrated in  FIG. 25  as those of the program indicated in the above first embodiment (see  FIG. 4 ). 
     The configuration of the program illustrated in  FIG. 25  is different from that of the program executed by the terminal apparatus according to the first embodiment illustrated in  FIG. 4  in that, for example, a standby processing unit PG 109  is added. 
     The standby processing unit PG 109  added to the present embodiment causes the control unit  110  to operate as a component to put processing to transmit a request to another terminal apparatus on standby until an arbitrary time passes when contents acquired from the delivery apparatus  200  are defective. 
     Other components are the same as those in the above first embodiment and thus, a description thereof is omitted. 
     [2. Recording processing in the request unit PG 100  according to the second embodiment]  FIG. 26  illustrates the flow of recording processing in the request unit PG 100  performed by a terminal apparatus according to the second embodiment. 
     The processing procedure illustrated in  FIG. 26  is performed by the control unit  110  operating as a component according to the broadcasting receiving unit PG 104 , the verification information receiving unit PG 105 , the verification processing unit PG 106 , the owning candidate search unit PG 107 , the complementary processing unit PG 108 , the standby processing unit PG 109 , or the like held by the request unit PG 100  illustrated in  FIG. 25 . 
     The same reference numerals are attached to processing procedures in the flow of processing illustrated in  FIG. 26  of the same content as that of recording processing according to the first embodiment illustrated in  FIG. 8 . 
     The processing procedure illustrated in  FIG. 26  is different from that illustrated in  FIG. 8  in that processing S 413  is added. 
     Thus, for simplification of description, the description of processing procedures of the same content is partially omitted. 
     Like the processing S 405  in the first embodiment, the control unit  110  of the terminal apparatus  100  according to the present embodiment performs verification processing of consistency of contents data included in contents information using the verification data  1143  included in the verification information acquired in the processing S 404  (S 405 ). 
     If, as a result of performing the above processing S 405 , the control unit  110  judges that the contents data is defective (YES at S 406 ), the control unit  110  performs standby processing, which is specific to the present embodiment (S 413 ). 
     In the above standby processing (S 413 ), the standby time may be set based on a random number or a logical distance between the local terminal apparatus and a terminal apparatus selected as the management node. 
     Here, as the logical distance, a difference between the node ID of the local terminal apparatus and that of the terminal apparatus selected as the management node may be used. 
     The control unit  110  divides a numeric value obtained based on the above random number or logical distance by the preset maximum wait time and sets the remainder thereof as the standby time. 
     Then, the control unit  110  measures the passage of time, and performs the search processing for retrieving a candidate that owns the contents after the standby time passes (S 407 ). 
     Processing thereafter is the same as that in the first embodiment and thus, a description thereof is omitted. 
     Timing of performing the above standby processing may be changed where appropriate in a stage before a search request is transmitted to the management node in the above search processing (S 407 ) of an owning candidate. 
     The foregoing is the flow of recording processing in the management unit PG 200  performed by the terminal apparatus  100  according to the second embodiment. 
     Third Embodiment 
     [1. Configuration of a program executed by the terminal apparatus according to the third embodiment]  FIG. 27  illustrates the configuration of a program executed by the terminal apparatus according to the present embodiment. 
     The same reference numerals are attached to the same components of the program illustrated in  FIG. 27  as those of the program indicated in the above first embodiment (see  FIG. 4 ). 
     The configuration of the program illustrated in  FIG. 27  is different from that of the program executed by the terminal apparatus according to the first embodiment illustrated in  FIG. 4  in that, for example, a reservation information transmission unit PG 205  is added. 
     The reservation information transmission unit PG 205  added to the present embodiment causes the control unit  110  to operate as a component to transmit reservation information received by the control unit  110  operating as a component according to the reservation receiving unit PG 202  to a terminal apparatus registered in the reservation terminal list PG 210 . 
     Other components are the same as those in the first embodiment and thus, a description thereof is omitted. 
     [2. Diagram illustrating the flow of processing of a system according to the third embodiment]  FIG. 28  is a diagram illustrating the flow of processing of a system according to the present embodiment. 
     In the example illustrated in  FIG. 28 , the same reference numerals are attached to the same processing as the flow of processing in the system illustrated in the above first embodiment (see  FIG. 5 ). 
     The flow of processing illustrated in  FIG. 28  is different from that of processing illustrated in  FIG. 5  in that transmission processing S 109  of reservation information is added. 
     Thus, for simplification of description, the description of processing procedures of the same content is partially omitted. 
     Like  FIG. 5 , the example illustrated in  FIG. 28  illustrates the flow of processing in which the terminal apparatus A ( 100 ) participating in a system according to the present embodiment and the terminal apparatus A ( 100 ) receives contents from the system according to the present embodiment. 
     First, the terminal apparatus A participates in a P2P system, according to a procedure similar to that in the first embodiment (S 100  to S 101 ). 
     When an instruction to make a reservation to receive delivery of contents by an input operation of the operator is received, the terminal apparatus A stores reservation details in the storage unit  120  and transmits reservation information indicating the reservation details to the management node identified based on the reserved details (S 102 ). 
     The terminal apparatus C searches for the terminal apparatus registered in the reservation terminal list by associating the same contents ID with the contents ID indicated in the reservation information received from the terminal apparatus A. 
     That is, the control unit  110  operating as a component according to the reservation receiving unit PG 202  held by the management unit PG 200  illustrated in  FIG. 27  searches the reservation terminal list PG 210  held in the storage unit  120  for the corresponding reservation information using the contents ID indicated in the reservation information received via the communication unit  140 . 
     Here, the terminal apparatus B is registered in the reservation terminal list of the terminal apparatus C by associating the same contents ID with the contents ID indicated in the reservation information received from the terminal apparatus A. 
     The terminal apparatus C transmits the reservation information received from the terminal apparatus A to the terminal apparatus B registered in the reservation terminal list (S 109 ). 
     That is, the control unit  110  operating as a component according to the reservation information transmission unit PG 205  held by the management unit PG 200  illustrated in  FIG. 27  transmits the reservation information via the communication unit  140 . 
     The terminal apparatus B updates the reservation terminal list stored in the storage unit  120  based on the reservation information received from the terminal apparatus C. 
     That is, the control unit  110  operating as a component according to the reservation receiving unit PG 202  held by the management unit PG 200  illustrated in  FIG. 27  registers the reservation information received via the communication unit  140  in the reservation terminal list PG 210  held in the storage unit  120 . 
     The terminal apparatus C transmits the reservation information registered in the reservation terminal list to the terminal apparatus A that has transmitted the reservation information. 
     That is, the control unit  110  operating as a component according to the reservation information transmission unit PG 205  held by the management unit PG 200  illustrated in  FIG. 27  transmits the reservation information via the communication unit  140 . 
     The terminal apparatus A updates the reservation terminal list stored in the storage unit  120  based on the reservation information received from the terminal apparatus C. 
     That is, the control unit  110  operating as a component according to the reservation receiving unit PG 202  held by the management unit PG 200  illustrated in  FIG. 27  registers the reservation information received via the communication unit  140  in the reservation terminal list PG 210  held in the storage unit  120 . 
     The terminal apparatus C updates the reservation terminal list stored in the storage unit  120  based on the reservation information received from the terminal apparatus A. 
       FIG. 15  illustrates an example of the reservation terminal list held by the terminal apparatus C. 
     The example illustrated in  FIG. 15  indicates that information to identify the contents A- 4  is registered as the contents ID  1501 , and an address  1  of the terminal apparatus A and an address  2  of the terminal apparatus B are registered as information indicating addresses of terminal apparatuses that have transmitted reservation information for the contents A- 4 . 
     Subsequent processing is the same as the flow of processing of the system according to the first embodiment and thus, a description thereof is omitted. 
     With the above processing, reservation information transmitted to the terminal apparatus selected as the management node may be shared by each terminal apparatus. 
       FIG. 29  conceptually illustrates the flow of reservation information shared in a system according to the present embodiment. 
     In  FIG. 29 , black dots A, B, C, and D represent terminal apparatuses and are called terminal apparatuses A, B, C, and D respectively. 
       FIG. 29  illustrates that the terminal apparatus A has information about the terminal apparatus B registered in the reservation terminal list. 
       FIG. 29  illustrates that the terminal apparatus B has information about the terminal apparatus A registered in the reservation terminal list. 
       FIG. 29  illustrates that the terminal apparatus D has information about the terminal apparatus A and the terminal apparatus B registered in the reservation terminal list. 
       FIG. 29  illustrates that the terminal apparatus C transmits ( 1 ) reservation information generated after an operation from a user being accepted to the terminal apparatus D selected as the management node. 
       FIG. 29  illustrates that the terminal apparatus D transmits ( 2 ,  3 ) the reservation information received from the terminal apparatus C to the terminal apparatuses A and B registered in the reservation terminal list. 
       FIG. 29  illustrates that the terminal apparatus D transmits ( 4 ) reservation information generated based on terminal information about the terminal apparatuses A and B registered in the reservation terminal list to the terminal apparatus C, which is the transmission source of the reservation information. 
       FIG. 29  illustrates that the terminal apparatus C registers the reservation information received from the terminal apparatus D in the reservation terminal list. 
       FIG. 29  illustrates that the terminal apparatus D registers the reservation information received from the terminal apparatus C in the reservation terminal list. 
       FIG. 29  illustrates that the terminal apparatus A transmits ( 5 ) the reservation information about the terminal apparatus C received from the terminal apparatus D to the terminal apparatus B registered in the reservation terminal list. 
       FIG. 29  illustrates that the terminal apparatus A registers the reservation information about the terminal apparatus C received from the terminal apparatus D in the reservation terminal list. 
       FIG. 29  illustrates that the terminal apparatus B transmits ( 6 ) the reservation information about the terminal apparatus C received from the terminal apparatus D to the terminal apparatus A registered in the reservation terminal list. 
       FIG. 29  illustrates that the terminal apparatus B registers the reservation information about the terminal apparatus C received from the terminal apparatus D in the reservation terminal list. 
     [3. Flow of reservation processing in the management unit PG 200  in the third embodiment]  FIG. 30  illustrates a procedure for reservation processing in the management unit PG 200  performed by the terminal apparatus according to the third embodiment. 
     In the example illustrated in  FIG. 30 , the same reference numerals are attached to the same processing as the flow of reservation processing in the management unit PG 200  indicated in the above first embodiment (see  FIG. 7 ). 
     The flow of processing illustrated in  FIG. 30  is different from that of processing illustrated in  FIG. 7  in that, for example, transmission processing S 302  to S 307  of reservation information is added. 
     Thus, for simplification of description, the description of processing procedures of the same content is partially omitted. 
     First, the control unit  110  of the terminal apparatus judges whether reception of reservation information is detected (S 300 ). 
     If the control unit  110  analyzes a received message acquired from the communication unit  140  via the communication line  130  and judges that the received message indicates reservation information, the control unit  110  judges that reception of the reservation information is detected (YES at S 300 ). 
     If the control unit  110  detects reception of reservation information (YES at S 300 ), the control unit  110  references terminal information included in the reservation information acquired from the communication unit  140  to judge whether the terminal information indicates the local terminal apparatus (S 302 ). 
     If, for example, address information indicated in the terminal information is the same as that allocated to the local terminal apparatus, the control unit  110  judges that the terminal information indicates the local terminal apparatus (YES at S 302 ). 
     If, for example, the node ID indicated in the terminal information is the same as that allocated to the local terminal apparatus, the control unit  110  also judges that the terminal information indicates the local terminal apparatus (YES at S 302 ). 
     If the control unit  110  judges that the terminal information included in the received reservation information does not indicate the local terminal apparatus (NO at S 302 ), the control unit  110  searches the reservation terminal list PG 210  based on the received reservation information (S 303 ). 
     That is, the control unit  110  searches for the terminal apparatus registered in the reservation terminal list PG 210  corresponding to the same contents ID as the contents ID indicated in the received reservation information (S 303 ). 
     On the other hand, if the control unit  110  judges in the above processing S 302  that the terminal information included in the received reservation information indicates the local terminal apparatus (YES at S 302 ), the control unit  110  performs the processing S 300  again. 
     The control unit  110  references terminal information acquired from the reservation terminal list by the search processing in the above processing S 303  to judge whether terminal information included in the reservation information received in the above processing S 300  is registered in the reservation terminal list PG 210  (S 304 ). 
     For example, if the control unit  110  compares terminal information included in the reservation information received in the above processing S 300  with terminal information acquired by the search processing in the above processing S 303  and terminal information having the same value is present, the control unit  110  judges that the terminal information included in the reservation information received in the above processing S 300  is registered in the reservation terminal list PG 210 . 
     If the control unit  110  compares terminal information included in the reservation information received in the above processing S 300  with terminal information acquired by the search processing in the above processing S 303  and there is no terminal information having the same value, the control unit  110  judges that the terminal information included in the reservation information received in the above processing S 300  is not registered in the reservation terminal list PG 210 . 
     If the control unit  110  judges that terminal information is not registered in the above processing S 304  (YES at S 304 ), the control unit  110  transmits, via the communication unit  140 , the reservation information received in the above processing S 300  to the terminal apparatus indicated in the terminal information acquired by the search processing in the above processing S 303  (S 305 ). 
     The reservation terminal list includes the contents ID and terminal information. 
     The terminal information  2102  may be a node ID or address information. 
     The control unit  110  judges whether the terminal apparatus indicated by the terminal information included in the reservation information received in the above processing S 300  matches the terminal apparatus that is the transmission source of the reservation information (S 306 ). 
     The control unit  110  may determine the transmission source terminal apparatus by analyzing a received message acquired from the communication unit  140  in the above processing S 300 . 
     For example, the transmission source terminal apparatus may be determined by referencing the transmission source IP address (Source Address) indicated in the IP (Internet Protocol) header included in the received message. 
     If the control unit  110  judges that the terminal apparatus indicated by the terminal information included in the reservation information received in the above processing S 300  matches the terminal apparatus that is the transmission source of the reservation information (YES at S 306 ), the control unit  110  transmits reservation information having the terminal information and contents ID acquired by the search processing in the above processing S 303  to the terminal apparatus which is the transmission source of the received reservation information (S 307 ). 
     The control unit  110  registers reservation terminal information having the contents ID  2101  and the terminal information  2102  in the reservation terminal list PG 210  based on the contents ID and terminal information indicated in the reservation information received in the above processing S 300  (S 301 ). 
     Here, the terminal information  2102  may be a node ID or address information. 
     On the other hand, if the control unit  110  judges in the above processing S 306  that the terminal apparatus indicated by the terminal information included in the reservation information does not match the terminal apparatus that is the transmission source of the reservation information (NO at S 306 ), the control unit  110  performs registration processing in the above processing S 301  without performing the above processing S 307 . 
     The foregoing is the flow of reservation processing in the management unit PG 200  performed by the terminal apparatus  100  according to the present embodiment. 
     [4. Owning candidate search processing in the request unit  100  in the third embodiment] 
       FIG. 31  illustrates a procedure for owning candidate search processing in the request unit PG 100  performed by the terminal apparatus according to the third embodiment. 
     In the example illustrated in  FIG. 31 , the same reference numerals are attached to the same processing as the flow of owning candidate search processing in the request unit PG 100  indicated in the above first embodiment (see  FIG. 9 ). 
     The flow of processing illustrated in  FIG. 31  is different from that of processing illustrated in  FIG. 9  in that, for example, the selection processing (S 502 ) of the management node is deleted. 
     Thus, for simplification of description, the description of processing procedures of the same content is partially omitted. 
     First, the control unit  110  starts owning candidate search processing by performing verification processing on received contents (S 405  in  FIG. 8 ) according to a processing procedure similar to that for the flow of recording processing in the request unit PG 100  indicated in the first embodiment (see  FIG. 8 ) and performing search processing of owning candidates by specifying the contents ID of contents judged to be defective (S 407  in  FIG. 8 ). 
     That is, the control unit  110  starts owning candidate search processing after the contents ID are specified (S 500 ). 
     Here, the contents ID is a contents ID corresponding to contents data judged to be defective by the verification processing performed in the above processing S 405 . 
     The control unit  110  judges whether information about an owning candidate is present (S 501 ). 
     If, for example, the control unit  110  has acquired information about an owning candidate from the management unit PG 200  performed by the local terminal apparatus, the control unit  110  judges that information about an owning candidate is present (NO at S 501 ). 
     If the control unit  110  judges in the above processing S 501  that information about an owning candidate is present (NO at S 501 ), the control unit  110  outputs information about owning candidates already held as a search result (S 506 ). 
     On the other hand, if the control unit  110  judges in the above processing S 501  that information about an owning candidate is not present (YES at S 501 ), the control unit  110  transmits a search request to the management unit PG 200  performed by the local terminal apparatus using a technique such as inter-process communication (S 503 ). 
     The control unit  110  receives a terminal list as a search result from the transmission destination of the search request (S 504 ) and registers the received terminal list in the owning candidate DB PG 116  (S 505 ). 
     The terminal list received in the above processing S 504  includes the contents ID and terminal information. 
     The terminal information may be a node ID or address information. 
     If the node ID is used as the terminal information, the address information  1102  may be acquired by referencing the terminal list PG 110 . 
     The control unit  110  outputs the terminal list received in the above processing S 504  as an owning candidate (S 506 ). 
     The foregoing is the flow of owning candidate search processing in the request unit PG 100  performed by the terminal apparatus  100  according to the present embodiment. 
     Owning candidate search processing in the management unit PG 200  performed by the terminal apparatus according to the present embodiment is the same as that in the first embodiment and thus, a description thereof is omitted. 
     Fourth Embodiment 
     [1. Overview of the fourth embodiment] The present embodiment has a configuration similar to that of the third embodiment to which standby processing similar to that in the second embodiment is added. 
     However, the standby processing in the present embodiment puts execution of transmission processing of an acquisition request to request transmission of complementary information on standby until an arbitrary time passes. 
     In a description that follows, the description of content similar to that in the third embodiment is partially omitted. 
     [2. Configuration of a program executed by the terminal apparatus according to the fourth embodiment]  FIG. 32  illustrates the configuration of a program executed by the terminal apparatus according to the present embodiment. 
     The same reference numerals are attached to the same components of the program illustrated in  FIG. 32  as those of the program indicated in the above third embodiment (see  FIG. 27 ). 
     The configuration of the program illustrated in  FIG. 32  is different from that of the program according to the third embodiment illustrated in  FIG. 27  in that, for example, the standby processing unit PG 109  is added. 
     The standby processing unit PG 109  added to the present embodiment is a software component that causes the control unit  110  to operate as a component that puts processing to transmit a request to other terminal apparatuses on standby until an arbitrary time passes when contents acquired from the delivery apparatus  200  are defective. 
     Other components are the same as those in the third embodiment and thus, a description thereof is omitted. 
     [3. Recording processing in the request unit PG 100  according to the fourth embodiment]  FIG. 33  illustrates the flow of recording processing in the request unit PG 100  performed by a terminal apparatus according to the fourth embodiment. 
     The processing procedure illustrated in  FIG. 33  is performed by the control unit  110  operating as a component according to the broadcasting receiving unit PG 104 , the verification information receiving unit PG 105 , the verification processing unit PG 106 , the owning candidate search unit PG 107 , the complementary processing unit PG 108 , the standby processing unit PG 109 , or the like held by the request unit PG 100  illustrated in  FIG. 32 . 
     First, the control unit  110  of the terminal apparatus judges whether verification information is received (S 400 ). 
     If the control unit  110  analyzes a received message acquired from the communication unit  140  via the communication line  130  and judges that the received message indicates verification information, the control unit  110  judges that verification information is received (YES at S 400 ). 
     If the control unit  110  judges that verification information is received (YES at S 400 ), the control unit  110  registers the received verification information in the verification information DB PG 114 . 
     As illustrated in  FIG. 20 , the verification information includes the contents ID  1141 , the divided contents ID  1142 , and verification data  1143 . 
     As the verification data, for example, a hash value obtained by hashing contents data divided into certain time units may be used. 
     If the control unit  110  judges in the above processing S 400  that no verification information is received (NO at S 400 ), the control unit  110  judges whether or not contents are received (S 402 ). 
     If the control unit  110  analyzes a received message acquired from the communication unit  140  via the communication line  130  and judges that the received message indicates contents information, the control unit  110  judges that contents are received (YES at S 402 ). 
     If the control unit  110  judges that contents information is received (YES at S 402 ), the control unit  110  registers the received contents information in the contents DB PG 115  and contents management information indicating a state of the received contents information in the contents management table PG 112  (S 403 ). 
     As illustrated in  FIG. 21 , the contents information includes the contents ID  1151 , the divided contents ID  1152 , and the contents data  1153 . 
     The contents data  1153  is contents data obtained by dividing contents identified by the contents ID  1151  into certain time units or the like. 
     As illustrated in  FIG. 18 , the contents management information includes the contents ID  1121 , the divided contents ID  1122 , and the state information  1123 . 
     The state information  1123  indicates a result of verification processing performed on contents data included in the contents information. 
     The state information  1123  has, for example, a value indicating “not verified” before verification processing being performed stored therein. 
     If, as a result of performing verification processing, consistency with the verification information is found, a value indicating “consistent” is stored, and if no consistency with the verification information is found, a value indicating “not consistent” is stored. 
     Contents information received by the radio receiver  500  may not include the divided contents ID. 
     In this case, contents data included in contents information received by the radio receiver  500  may be reconfigured into units for verification processing with the sequence number indicating the reconfigured order attached by the terminal apparatus  100 . 
     That is, in this example, the above sequence number may be used as the divided contents ID included in contents information and verification information. 
     Next, the control unit  110  acquires verification information corresponding to the contents ID and divided contents ID included in the contents information registered in the contents DB in the above processing S 403  from the verification information DB (S 404 ). 
     The control unit  110  uses the verification data  1143  included in the acquired verification information to perform verification processing of consistency of contents data included in the contents information. 
     The control unit  110  compares, for example, a hash value generated from the contents data using the same algorithm as that used for generating verification data with the verification data and if both values match, the control unit  110  may judge that the contents data is consistent (No at S 406 ). 
     That is, if the control unit  110  judges that contents data is not defective (NO at S 406 ), the control unit  110  performs processing in the above processing S 400  and thereafter. 
     On the other hand, if, as a result of performing the above processing S 405 , the control unit  110  judges that contents data is defective (YES at S 406 ), the control unit  110  searches for an owning candidate indicating a terminal apparatus that may have data to complement defects (S 407 ). 
     An example of search processing in the processing S 407  will be described later. 
     The control unit  110  judges, as a result of performing search processing, whether an owning candidate is obtained (S 408 ). 
     If, as a result of performing the above search processing, the control unit  110  judges that an owning candidate is obtained (YES at S 408 ), the control unit  110  performs standby processing, which is specific to the present embodiment (S 413 ). 
     In the above standby processing (S 413 ), the standby time may be set based on a random number or the number of terminal apparatuses indicated by owning candidates acquired by the owning candidate search processing in the above processing S 407 . 
     The control unit  110  may decide the value of the maximum standby time based on, for example, the number of terminal apparatuses indicated by owning candidates acquired by the owning candidate search processing in the above processing S 407  and set the standby time randomly in the range of the decided value and 0. 
     Accordingly, the maximum standby time that may be set may be adjusted in accordance with the number of owning candidates. 
     That is, if the number of owning candidates increases, there is a possibility that the standby time performed in the above processing S 413  is set longer compared with a case of a smaller number of owning candidates. 
     As a result, in the present embodiment, concentration of acquisition requests transmitted from terminal apparatuses in a short time may effectively be avoided. 
     If, on the other hand, the number of owning candidates decreases, the maximum standby time performed in the above processing S 413  is set shorter compared to a case of a larger number of owning candidates. 
     This is because the possibility of acquisition requests transmitted from terminal apparatuses being concentrated in a short time decreases with a decreasing number of owning candidates. 
     That is, in this case, complementary processing may be completed earlier by setting the range of time in which timing to transmit an acquisition request is distributed shorter compared to a case of a larger number of owning candidates. 
     After the standby time passes, the control unit  110  transmits an acquisition request to request transmission of complementary information to the terminal apparatus indicated by an owning candidate acquired by the above search processing (S 409 ). 
     Here, the acquisition request transmitted to the terminal apparatus indicated by an owning candidate includes the contents ID and divided contents ID corresponding to contents data judged to be defective in the above verification processing. 
     Data organized in list form indicating a plurality of terminal apparatuses may be used as owning candidates acquired in the above search processing (S 407 ). 
     In this case, the control unit  110  may select terminal apparatuses indicated in the owning candidate list in any order to sequentially transmit an acquisition request to these terminal apparatuses or multicasting may be used (S 409 ). 
     On the other hand, if the control unit  110  judges in the above processing S 408  that acquisition of owning candidates failed (NO at S 408 ), the control unit  110  transmits an acquisition request to request transmission of complementary information to the delivery apparatus  200  (S 412 ). 
     Here, the acquisition request transmitted to the delivery apparatus  200  includes the contents ID and divided contents ID corresponding to contents data judged to be defective in the above verification processing. 
     The control unit  110  receives complementary information from the transmission destination of the acquisition request (S 410 ) and performs complementary processing using the received complementary information (S 411 ). 
     Here, the complementary information received from the transmission destination of the acquisition request includes the contents ID, divided contents ID, and contents data. 
     That is, in the above complementary processing, the control unit  110  searches the contents DB PG 115  for contents information corresponding to the contents ID and divided contents ID included in the received complementary information. 
     Then, the control unit  110  updates contents data included in the searched contents information by using contents data included in the received complementary information. 
     If the transmission destination of the acquisition request does not own consistent contents data, the control unit  110  receives incomplete complementary information in the above processing S 410 . 
     In this case, the control unit  110  discards the complementary information without performing the above processing S 411  and may perform reception processing of complementary information from the terminal apparatus of another owning candidate or from the delivery apparatus. 
     The foregoing is the flow of recording processing in the request unit PG 100  performed by the terminal apparatus  100 . 
     In the above example, recording processing using the terminal apparatus  100  is described and the above complementary processing may be performed when delivered contents are reproduced. 
     Fifth Embodiment 
     [1. Configuration of a program executed by the terminal apparatus according to the fifth embodiment]  FIG. 34  illustrates the configuration of a program executed by the terminal apparatus according to the present embodiment. 
     The same reference numerals are attached to the same components of the program illustrated in  FIG. 34  as those of the program indicated in the above first embodiment (see  FIG. 4 ). 
     The configuration of the program illustrated in  FIG. 34  is different from that of the program according to the first embodiment illustrated in  FIG. 4  in that, for example, a response wait processing unit PG 206  is added. 
     The response wait processing unit PG 206  added to the present embodiment is a software component that causes the control unit  110  to operate as a component that puts transmission processing of a terminal list as a search result on standby until an arbitrary time passes when a search request of an owning candidate is received. 
     Other components are the same as those in the above embodiments and thus, a description thereof is omitted. 
     [2. Owning candidate search processing in the management unit performed by the terminal apparatus according to the fifth embodiment] In the flow of processing illustrated in  FIG. 35 , the same reference numerals are attached to processing procedures of the same content as that of owning candidate search processing in the first embodiment illustrated in  FIG. 10 . 
     The processing procedure illustrated in  FIG. 35  is different from that illustrated in  FIG. 10  in that, for example, processing S 604  and processing S 605  are added. 
     Thus, for simplification of description, the description of processing procedures of the same content is partially omitted. 
     First, the control unit  110  of the terminal apparatus  100  judges whether a search request is received (S 600 ). If the control unit  110  judges that a search request is received (YES at S 600 ), the control unit  110  sets a standby time in which execution of transmission processing of a terminal list is put on standby in the processing S 603  (S 604 ). 
     In the processing S 604 , the control unit  110  may set the standby time generated based on a random number. 
     In the processing S 604 , the control unit  110  may also set a standby time generated based on the number of search requests from other terminal apparatuses put on standby. 
     For example, the count value is incremented each time a search request is received in the processing S 600 , a standby time generated based on the count value is set in the processing S 604 , and the count value is decremented each time a terminal list is transmitted in the processing S 603 . 
     For example, the standby time may be set longer for a larger count value and shorter for a smaller count value in the processing S 604 . 
     Next, the control unit  110  puts execution of search processing (S 605 ) of owning candidates on standby until the set standby time passes. 
     In the processing S 605 , the control unit  110  may transmit a signal indicating that the search processing (S 605 ) is put on standby in a certain timing to terminal apparatuses until the standby time passes. 
     Before starting the processing S 605 , the control unit  110  may transmit a signal indicating that a search request is received to terminal apparatuses. 
     After the standby time passes, the control unit  110  performs search processing (S 601 ) of a reservation terminal. 
     Subsequent processing is the same as that in the first embodiment and thus, a description thereof is omitted. 
     Sixth Embodiment 
     [1. Configuration of a program executed by the terminal apparatus according to the sixth embodiment]  FIG. 36  illustrates the configuration of a program executed by the terminal apparatus according to the present embodiment. 
     The same reference numerals are attached to the same components of the program illustrated in  FIG. 36  as those of the program indicated in the above fifth embodiment (see  FIG. 34 ). 
     The configuration of the program illustrated in  FIG. 36  is different from that of the program according to the fifth embodiment illustrated in  FIG. 34  in that, for example, a connection result transmission unit PG 209 , a connection result receiving unit PG 207 , a connection result update unit PG 208 , and a connection result list PG 220  are added. 
     The connection result transmission unit PG 209  is a software component that causes the control unit  110  to operate as a component that transmits connection result information indicating a transmission and/or reception result of complementary information in a process of the complementary processing unit PG 108  to the management node using the communication unit  140 . 
     Here, the connection result information includes the contents ID, terminal information, and a connection result. 
     The contents ID of contents corresponding to complementary information in the process of the complementary processing unit PG 108  is set as the contents ID indicated in the connection result information. 
     Information to identify the terminal apparatus that performs the complementary processing unit PG 108  is set as the terminal information indicated in the connection result information. 
     The connection result indicated in the connection result information indicates a transmission and/or reception result of complementary information in the process of the complementary processing unit PG 108 . 
     The connection result receiving unit PG 207  causes the control unit  110  to operate as a component that receives connection result information transmitted by a process of the connection result transmission unit PG 209  by using the communication unit  140 . 
     The connection result update unit PG 208  is a software component that causes the control unit  110  to operate as a component that updates a connection result list PG 220  based on connection result information received by a process of the connection result receiving unit PG 207 . 
     The response wait processing unit PG 206  according to the present embodiment is a software component that causes the control unit  110  to operate as a component that sets the standby time based on the connection result list PG 220 . 
       FIG. 37  illustrates the data structure of a connection result list according to the present embodiment. 
     The connection result list illustrated in  FIG. 37  includes a contents ID  2201 , terminal information  2202 , and a connection result  2203 . 
     The contents ID indicated in connection result information received by the process of the connection result receiving unit PG 207  is set as the contents ID  2201  illustrated in  FIG. 37 . 
     That is, the contents ID of contents corresponding to complementary information in the process of the complementary processing unit PG 108  is set. 
     The terminal information indicated in connection result information received by the process of the connection result receiving unit PG 207  is set as the terminal information  2202  illustrated in  FIG. 37 . 
     That is, information to identify the terminal apparatus that has transmitted connection result information is set. 
     For example, the IP address, node ID, and the like of a terminal apparatus may be used as the terminal information. 
     The connection result indicated in connection result information received by the process of the connection result receiving unit PG 207  is set as the connection result  2203  illustrated in  FIG. 37 . 
     In the example illustrated in  FIG. 37 , the connection results ( 2203 ) of the terminal apparatuses A to G are indicated in association with the contents ID ( 2201 ) “contents A- 4 ”. 
     In the example illustrated in  FIG. 37 , “S1” indicating a state in which no terminal list is transmitted after a search request is accepted is set as a connection result of the terminal apparatuses A and G. 
     In the example illustrated in  FIG. 37 , “S2” indicating a state in which reception of complementary information is not completed after the terminal list is transmitted is set as a connection result of the terminal apparatuses E and F. 
     In the example illustrated in  FIG. 37 , “S3” indicating a state in which reception of complementary information is completed is set as a connection result of the terminal apparatuses B and C. 
     Other components are the same as those in the above embodiments and thus, a description thereof is omitted. 
     [2. Flow of processing in a system according to the sixth embodiment]  FIG. 39  illustrates the flow of processing of a system according to the sixth embodiment. 
     In the example illustrated in  FIG. 39 , the same reference numerals are attached to the same processing as the flow of processing in the system indicated in the above first embodiment (see  FIG. 5 ). 
     The flow of processing illustrated in  FIG. 39  is different from that of processing illustrated in  FIG. 5  in that, for example, transmission processing S 110  of a connection result is added. 
     Thus, for simplification of description, the description of processing procedures of the same content is partially omitted. 
     Like  FIG. 5 , the example illustrated in  FIG. 39  illustrates the flow of processing that the terminal apparatus A ( 100 ) receives contents from a system according to the present embodiment. 
     However, among four terminal apparatuses of the terminal apparatus A to the terminal apparatus D, the terminal apparatus D functions as the management node and the terminal apparatus A to the terminal apparatus C function as ordinary nodes. 
     First, like the first embodiment, the terminal apparatus A transmits a search request to obtain the location of a terminal apparatus owning complementary information of an applicable location to the terminal apparatus D operating as the management node. 
     If the search request is received, the terminal apparatus D updates the connection result list based on details of the received search request. 
     That is, the terminal apparatus D sets “S1” to the connection result ( 2203 ) registered in association with the contents ID indicated in the received search request and the terminal apparatus that has transmitted the search request. 
     Here, “S1” indicates a state in which no terminal list is transmitted after a search request is accepted. 
     After the standby time set based on the connection result list (PG 220 ) passes, the terminal apparatus D transmits a terminal list generated based on reservation terminal information acquired in a similar way as in the first embodiment to the terminal apparatus A that has transmitted the search request (S 106 ). 
     At this point, the terminal apparatus D updates the connection result list PG 220 . 
     That is, the terminal apparatus D sets “S2” to the connection result  2203  registered by associating with the contents ID indicated in the received search request and the terminal apparatus that has transmitted the search request. 
     Here, “S2” indicates a state in which reception of complementary information is not completed after the terminal list is transmitted. 
     The terminal apparatus A transmits an acquisition request to acquire complementary information of contents to the terminal apparatus indicated in the received terminal list (S 107 ). 
     The example illustrated in  FIG. 39  illustrates that when an acquisition request is transmitted to the terminal apparatus B, communication with the terminal apparatus B fails. 
     In the example illustrated in  FIG. 39 , the terminal apparatus A further transmits an acquisition request to acquire complementary information of contents to the terminal apparatus C, which is another terminal apparatus indicated in the received terminal list (S 107 ′). 
     The terminal apparatus C acquires divided contents data corresponding to the contents ID and divided contents ID indicated in the received acquisition request from the contents DB PG 115 . 
     The terminal apparatus C transmits the acquired divided contents data as complementary information to the terminal apparatus A that has transmitted the acquisition request (S 108 ). 
     The terminal apparatus A updates divided contents data stored in the contents DB PG 115  by associating the contents ID with divided contents ID indicated in the received complementary information by using the divided contents data included in the received complementary information. 
     The terminal apparatus A transmits connection result information indicating transmission results of an acquisition request to the terminal apparatuses B and C and a reception result of complementary information to the terminal apparatus D operating as the management node (S 110 ). 
     The terminal apparatus D updates the connection result list PG 220  based on the connection result information received from the terminal apparatus A. 
       FIG. 38  illustrates an example of the connection result list after being updated by the processing  5110  illustrated in  FIG. 39 . 
     In the example illustrated in  FIG. 38 , “S3” indicating that reception of complementary information is completed is set to the connection result ( 2203 ) associated with the terminal apparatus A. 
     In the example illustrated in  FIG. 38 , “S0” indicating that transmission processing of an acquisition request of complementary information failed is set to the connection result ( 2203 ) associated with the terminal apparatus B. 
     This illustrates an example in which the connection result list is updated based on a failure of transmission processing of an acquisition request from the terminal apparatus A to the terminal apparatus B in the processing S 107  illustrated in  FIG. 39 . 
     The foregoing is the flow of processing of a whole system according to the present embodiment. 
     [3. Setting processing of the standby time according to the sixth embodiment] Next, setting processing of the standby time according to the present embodiment will be described. 
     The overall flow of owning candidate search processing in the management unit PG 200  performed by a terminal apparatus according to the present embodiment is similar to the processing procedures according to the fifth embodiment illustrated in  FIG. 35  and thus, a description thereof is omitted. 
     First, the control unit  110  detects connection result information registered correspondingly to the contents ID indicated in the search request received in the processing S 600  from the connection result list PG 220 . 
     The control unit  110  counts the number of pieces of connection result information whose connection result ( 2203 ) is “S2” of the detected connection result information. 
     That is, the number of pieces of connection result information indicating a state in which reception of complementary information is not completed after a terminal list being transmitted is counted. 
     The control unit  110  sets the standby time based on the number of pieces of counted “S2” connection result information. 
     For example, the control unit  110  may set the standby time longer with an increasing number of pieces of “S2” connection result information and shorter with a decreasing number of pieces of “S2” connection result information. 
     The control unit  110  may also set an arbitrary standby time based on a random number if the number of counted “S2” connection result information is equal to or more than a certain threshold and set the standby time to 0 if the number of counted “S2” connection result information is less than the certain threshold. 
     That is, when the number of pieces of “S2” connection result information is less than the certain threshold, transmission processing of a terminal list is performed without performing standby processing. 
     It is highly probable that terminal apparatuses in a state in which reception of complementary information is not completed after a terminal list being transmitted are performing reception processing of complementary information from another terminal apparatus. 
     That is, with an increasing number of terminal apparatuses in a state in which reception of complementary information is not completed after a terminal list being transmitted, the number of terminal apparatuses performing reception processing of complementary information increases. 
     Thus, by setting the standby time in accordance with the number of terminal apparatuses in a state in which reception of complementary information is not completed after a terminal list being transmitted, an overload of a network by transmission and/or reception processing of complementary information being concentrated may be avoided. 
     Other Embodiments 
     All or a portion of processing described as being automatically performed among processes described in the above embodiments may manually be performed. 
     Or, all or a portion of processing described as being manually performed may automatically be performed by a known method. 
     Further, all or a portion of processing performed by each apparatus indicated in the present embodiment may be realized by hardware based on wired logic.