Patent Publication Number: US-2002010752-A1

Title: Information processing apparatus, method thereof, information processing system, and medium

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Field of the invention  
       [0002] The present invention relates to an information processing apparatus connected to, say, an IEEE 1394 serial data bus, method thereof, information processing system, and medium.  
       [0003] 2. Description of Related Art  
       [0004] In recent years, there have been developed AV devices capable of mutually transmitting information via a network using, say, an IEEE 1394 serial data bus standardized by IEEE (The institute of Electrical and Electronics Engineers). This network system can mutually control AV devices connected to the above network by using specified digital interface commands (hereafter referred to as AV/C commands) according to the AV/C Command Transaction Set.  
       [0005]FIG. 1 shows a configuration example of a network using the IEEE  1394  serial data bus. The network system in FIG. 1 comprises an IRD (Integrated Receiver Decoder)  71  and a DVCR (digital video cassette recorder)  81  such as D-VHS connected to an IEEE 1394 serial data bus  80  (hereafter referred to as the bus  80 ).  
       [0006] A controller  72  of the IRD  71  accepts various user&#39;s functional instructions such as selecting channels, reserving programs, and the like for controlling IRD  71  operations. The controller  72  should be able to control the DVCR  81  by using AV/C commands as specified digital interface commands. ACS antenna  74  receives a digital signal for digital satellite broadcasting transmitted from a communication satellite (not shown) and outputs the reception signal to a tuner subunit  73 . Under control of the controller  72 , the tuner subunit  73  extracts a specified channel signal from the digital signal input from the CS antenna  74  and outputs the extracted signal to a VCR subunit  84  of the DVCR  81  via the bus  80 .  
       [0007] A controller  82  of the DVCR  81  accepts various user&#39;s functional instructions such as reproduction, recording, fast forward, rewind, recording reservation, and the like for controlling overall operations of the DVCR  81 . Under control of the controller  82 , an analog tuner subunit  83  extracts a specified channel signal from an input analog signal and outputs the extracted signal to the VCR subunit  84 .  
       [0008] The VCR subunit  84  records a picture signal on magnetic tape (not shown). Picture signals are input from an analog tuner subunit  83  or is supplied from the IRD  71 &#39;s tuner subunit  73  via the bus  80 .  
       [0009] An electronic device such as the IRD  71  or the DVCR  81  connected to the bus  80  is called a unit. For interaction between units, a descriptor is defined in the general specification for AVIC commands (AV/C Command Transaction Set), namely the AV/C Digital Interface Command Set General Specification (hereafter referred to as the AV/C general). The descriptor is used for mutually reading and writing information stored in respective units. The AV/C general is detailed in “AV/C Digital Interface Command Set General Specification (Version 3.0, Apr. 15, 1998)”. A functional entity given to the unit is called a subunit. In FIG. 1, examples are the IRD  71 &#39;s digital tuner subunit  73 , DVCR  81 &#39;s VCR subunit  84 , and the like.  
       [0010] Incidentally, the above-mentioned DVCR  81  is called a target device which can be controlled by another unit&#39;s controller, say, the IRD  71 &#39;s controller  72 . For example, there may be provided a subunit called an AV/C Bulletin Board Subunit (BBS). This is detailed in “AV/C Bulletin Board Subunit General Specification, Rev. 0.38”, 1394 Trade Association (Jan. 27, 1999). The BBS is provided as a space for allowing subunit-independent information to be shared among other units.  
       [0011] The BBS predefines one or a plurality of board types available to a BBSequipped device (target device). When the controller reads or writes the target device&#39;s BBS, the controller specifies and reads a root list ID for board types available to the target device. The controller then sends a write instruction to the target device. On the other hand, the target device returns an accept in response to the instruction sent from the controller (see AV/C BBS version 1.0).  
       [0012] According to this architecture, the controller is limited to handle just types of boards preinstalled on a target device. Consequently, it is not possible to fulfill a controller&#39;s request to handle a type of boards not installed on the target device.  
       [0013] Basically, when the BBS is used, the controller is responsible for writing. The target device is not responsible for the written contents. In the future, there can be a device which has a large amount of memory, is equipped with the BBS, provides a space for sharing information by the BBS, and does not deten-nine board types to be handled. In such a case, there may arise a request that the controller later create a controllable board type and control it.  
       [0014] However, the current standard does not specify a method of adding or creating a new board type for the BBS.  
       BRIEF SUMMARY OF THE INVENTION  
       [0015] The present invention has been made in consideration of the foregoing. It is therefore an object of the present invention to provide an information processing apparatus, method thereof, information processing system, and medium so that the controller can newly add a board type for the BBS.  
       [0016] An information processing apparatus according to the present invention comprises shared information storage means for storing information shareable among other networked information processing apparatuses and including one or more types of information description area. This apparatus solves the above-mentioned problems by responding to a request from the another networked information processing apparatus; and comprising information description area generation means for generating a new information description area having an identification information write area in which the another information processing apparatus writes identification information indicating a type of the information description area.  
       [0017] Further, an information processing method according to the present invention is applied to an information processing apparatus comprising shared information storage means for storing information shareable among other networked information processing apparatuses and including one or more types of information description area. This method solves the above-mentioned problems by responding to a request from the another networked information processing apparatus; and generating a new information description area having an identification information write area in which the another information processing apparatus writes identification information indicating a type of the information description area.  
       [0018] Next, an information processing apparatus according to the present invention solves the above-mentioned problems by comprising: request means for requesting to generate a specified type of information description area from another information processing apparatus having shared information storage means for storing information shareable among networked information processing apparatuses and including one or more types of information description area; and write means for writing identification information indicating the specified type of the information description area to a write area for identification information indicating a type of the information description area provided in the information description area newly generated by the another information processing apparatus in response to the request.  
       [0019] Moreover, an information processing apparatus according to the present invention solves the above-mentioned problems by: requesting to generate a specified type of information description area from another information processing apparatus having shared information storage means for storing information shareable among networked information processing apparatuses and including one or more types of information description area; and writing identification information indicating the specified type of the information description area to a write area for identification information indicating a type of the information description area provided in the information description area newly generated by the another information processing apparatus in response to the request.  
       [0020] Then, an information processing system according to the present invention solves the above-mentioned problems by at least comprising first and second information processing apparatuses. The first information processing apparatus comprises shared information storage means for storing information shareable among other networked information processing apparatuses and including one or more types of information description area and information description area generation means for, in response to a request from the another networked information processing apparatus, generating a new information description area having an identification information write area in which the another information processing apparatus writes identification information indicating a type of the information description area. The second information processing apparatus comprises request means for requesting the first information processing apparatus to generate a specified type of information description area and write means for writing identification information indicating the specified type of the information description area to a write area for the identification information indicating a type of the information description area provided in the information description area newly generated by the first information processing apparatus in response to the request.  
       [0021] Moreover, an information processing method according to the present invention solves the above-mentioned problems by requesting to generate a specified type of information description area from shared information storage means for storing information shareable among other networked information processing apparatuses and including one or more types of information description area, generating a new information description area having an identification information write area for writing identification information indicating a type of the information description area in response to the above request, and writing identification information indicating the specified type of the information description area to a write area for the identification information indicating a type of the information description area provided in the information description area newly generated in response to the above request.  
       [0022] A medium according to the present invention solves the above-mentioned problems by allowing an information processing apparatus to execute a program comprising the steps of: inputting an request from another networked information processing apparatus; and, in response to a request from the another networked information processing apparatus, generating a new information description area having an identification information write area in which the another information processing apparatus writes identification information indicating a type of the information description area.  
       [0023] A medium according to the present invention solves the above-mentioned problems by allowing an information processing apparatus to execute a program comprising the steps of: requesting to generate a specified type of information description area from another information processing apparatus having shared information storage means for storing information shareable among networked information processing apparatuses and including one or more types of information description area; and writing identification information indicating the specified type of the information description area to a write area for identification information indicating a type of the information description area provided in the information description area newly generated by the another information processing apparatus in response to the request.  
       [0024] A medium according to the present invention solves the above-mentioned problems by allowing an information processing apparatus to execute a program comprising the steps of: requesting to generate a specified type of information description area from shared information storage means for storing information shareable among networked information processing apparatuses and including one or more types of information description area; in response to the above request, generating a new information description area having an identification information write area for writing identification information indicating a type of the information description area; and writing identification information indicating the specified type of the information description area to a write area for identification information indicating a type of the information description area provided in the information description area newly generated in response to the above request.  
       [0025] According to the information processing apparatus, the method thereof, the information processing system, and the medium of the present invention, a request to generate a specified type of information description area is issued to shared information storage means for storing information shareable among networked information processing apparatuses and setting one or more types of information description area. In response to this request, there is generated a new information description area having an identification information write area for writing identification information indicating a type of the information description area. Identification information indicating the specified type of the information description area is written to a write area for identification information indicating a type of the information description area provided in the newly generated information description area. According to AV/C general specifications using an IEEE 1394 serial data bus, for example, the controller can newly add a BBS board type.  
       [0026] According to the present invention, the controller can later add a board type to a device which has a large amount of memory and the BBS, and provides networked devices with the BBS as a space for sharing information. The controller can handle, say, the most recent board type. Since the present invention allows a board type to be added later, it is unnecessary for memory to store a complete list of board types available to devices at the time of shipment. It is possible to newly create a list of board types according to user&#39;s selection, permitting an effective use of memory. 
     
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
     [0027]FIG. 1 is a block diagram showing a configuration example of an associated network system;  
     [0028]FIG. 2 is a block diagram showing a configuration example of a network system according to an embodiment of the present invention;  
     [0029]FIG. 3 is a block diagram showing a concrete configuration of an IRD;  
     [0030]FIG. 4 is a block diagram showing a concrete configuration of a DVCR;  
     [0031]FIG. 5 shows a structural model of a board type having a single board;  
     [0032]FIG. 6 shows a structural model of a board type having one or more boards;  
     [0033]FIG. 7 illustrates positioning of a general board type list according to the embodiment of the present invention;  
     [0034]FIG. 8 shows a detailed data structure of the board type list descriptor in FIG. 7;  
     [0035]FIG. 9 shows a detailed data structure of list_specific_information in FIG. 8;  
     [0036]FIG. 10 shows an allocation table of list IDs for the BBS version  1 . 0 ;  
     [0037]FIG. 11 shows an allocation table of list types;  
     [0038]FIG. 12 shows an allocation table of board types;  
     [0039]FIG. 13 is a flowchart showing a flow of process&#39;ng until a new board type is created in the system according to the embodiment of the present invention;  
     [0040]FIG. 14 is a flowchart showing another flow of processing until a new board type is created in the system according to the embodiment of the present invention;  
     [0041]FIG. 15 shows a WRITE OPEN command format;  
     [0042]FIG. 16 shows a READ command format;  
     [0043]FIG. 17 shows a CREATE command format;  
     [0044]FIG. 18 shows the content of the result field in FIG. 17;  
     [0045]FIG. 19 shows the format of subfunction_ 1 _specification for subfunction — 1=00 16  in FIG. 17;  
     [0046]FIG. 20 shows result field values and meanings thereof;  
     [0047]FIG. 21 shows the format of subfunction 13    1 _specification for subfunction — 1=01 16  in FIG. 17;  
     [0048]FIG. 22 shows field values in FIG. 21;  
     [0049]FIG. 23 shows a CLOSE command format;  
     [0050]FIG. 24 diagrams a detailed flow for creating a board type at step S 18  in FIGS. 13 and 14; and  
     [0051]FIG. 25 is a block diagram exemplifing a computer configuration according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0052] Embodiments of the present invention will be described in further detail with reference to the accompanying drawings. In this specification, the tenn “system” refers to a whole apparatus which comprises a plurality ofapparatuses, means, and the like.  
     [0053]FIG. 2 schematically shows a network system configuration according to an embodiment of the present invention.  
     [0054] The network system in FIG. 2 comprises an IRD  1  and a DVCR (digital video cassette recorder)  3  such as D-VHS connected to an IEEE 1394 serial data bus  2  (hereafter referred to as the bus  2 ). Obviously, the bus  2  can connect with not only IRD and DVCR, but also electronic devices equipped with IEEE 1394 terminals such as a personal computer, a hard disk drive, a CD player, a monitor, a digital video camera, an MD (trademark) player, and the like.  
     [0055] An IRD controller  11  in the IRD  1  accepts user&#39;s operations such as selecting channels or reserving programs for controlling overall operations of the IRD  1 . The controller  11  controls the DVCR  3  by using the above-mentioned AV/C commands as specified digital interface commands. A CS antenna  10  receives a digital signal for digital satellite broadcasting transmitted from a communication satellite (not shown) and outputs the reception signal to a tuner subunit  12 . Under control of the controller  11 , the tuner subunit  12  extracts a specified channel signal from the digital signal input from the CS antenna  10  and outputs the extracted signal to a VCR subunit  18  of the DVCR  3  via the bus  2 . Further, the controller  11  reads and writes a BBS (Bulletin Board Subunit)  16  of the DVCR  3 .  
     [0056] A controller  17  of the DVCR  3  accepts various user&#39;s operations such as instructing reproduction or reserving programs, and the like for controlling overall operations of the DVCR  3 . The controller  17  also reads and writes the BBS  16 . Under control of the controller  17 , an analog tuner subunit  15  extracts a specified channel signal from an input analog signal and outputs the extracted signal to the VCR subunit  18 .  
     [0057] The VCR subunit  18  records a picture signal on magnetic tape (not shown). Picture signals are input from an analog tuner subunit  15  or from the IRD l&#39;s tuner subunit  12  via the bus  2 .  
     [0058] The BBS  16  is provided as a space for allowing subunit-independent information to be shared among other units.  
     [0059]FIG. 3 shows a detailed configuration of the network system&#39;s IRD  1  in FIG. 2.  
     [0060] In FIG. 3, a signal is transmitted from the DVCR  3  or other units (not shown) via the bus  2  and is input to a CPU  22 , a major section of the controller  11 , via an IEEE 1394 interface  21 . According to the input signal, the CPU  22  generates a control signal for creating image data or GUI (Graphical User Interface) data for representing, say, menu screens and outputs the generated signal to a GUI engine  23 . The GUI engine  23  outputs the generated GUI data to an NTSC (National TV Standards Comnmittee) encoder  25  via the adder  23 . The GUI data is converted to NTSC data, is converted to an analog signal in a D/A converter  26 , and then is displayed on a monitor  6  as various menu screens. The CPU  22  also reads and writes the DVCR  3 &#39;s BBS.  
     [0061] A user operates an operation panel  27  or a remote coimnander (not shown) to select an intended device such as DVCR  3  and the like connected to the bus  2  and specify processing (function) to be performed by the selected device. When the user operates the remote commander, an infrared ray receiving section  28  receives an infrared ray signal representing the user&#39;s operation from the remote commander. The CPU  22  generates a control signal based on the signal input from the operation panel  27  or the infrared ray receiving section  28  for representing the user&#39;s operation. The control signal is output to an MPEG video decoder  34  and an MPEG audio decoder  35  or is supplied to the DVCR  3  via the IEEE 1394 interface  21  and the bus  2 . The CPU  22  receives a broadcast wave using the antenna  10  and displays it on the monitor m  6  or supplies it to the DVCR  3  and the like via the IEEE 1394 interface  21  and the bus  2 . It may be preferable to connect the monitor to the bus  2 .  
     [0062] The antenna  10  receives a broadcast wave from a satellite (not shown) and outputs it to a tuner  30  in the tuner subunit  12 . The tuner  30  selects a specified channel from the received broadcast wave according to the control signal input from the CPU  22 . A reception signal corresponding to the selected broadcast wave is demodulated and error corrected in a front end section  31 , and then is output to a descramble section  32 . An IC card (not shown) inserted into the IRD body stores cryptographic key information about subscribed channels. Out of the input data, the descramble section  32  outputs multiplexed data comprising only subscribed channel data to a demultiplexer  33  based on this cryptographic key information. The demultiplexer  33  sorts the input multiplexed data according to channels. Based on the input from CPU  22 , the demultiplexer extracts only user-specified channel data. The dernultiplexer outputs a video stream comprising picture packets to the MPEG video decoder  34  and an audio stream comprising speech packets to an MPEG audio decoder  35 .  
     [0063] The MPEG video decoder  34  decodes the video stream to restore video data before compression encoding and outputs the restored data to the NTSC encoder  25 . The NTSC encoder  25  converts video data to a brightness signal and a color-difference signal based on the NTSC system and outputs the converted signals as NTSC data to a D/A (digital/analog) converter  26 . The D/A converter  26  converts the NTSC data to an analog signal. This analog signal is sent to the monitor  6  for displaying pictures.  
     [0064] The MPEG audio decoder  35  decodes the audio stream to restore PCM (Pulse Code Modulation) audio data before compression encoding and outputs this data to the D/A converter  36 . The D/A converter  36  converts the PCM audio data to an analog signal, generating audio signals for R and L channels. These audio signals are sent to a speaker (not shown) mounted on the monitor  6 .  
     [0065] RAM  37  stores various programs and data for controlling and performing IRD  1  operations. When the IRD  1  is equipped with a hard disk drive, a hard disk can store these programs and data. The stored programs and data are read into the CPU  22  as needed. The RAM  37  is also provided with registers for maintaining descriptors compliant with the AV/C general. Work RAM  38  stores data and the like generated in accordance with program execution.  
     [0066] A drive  39  is connected to the CPU  22  and can be used for a magnetic disk  40 , an optical disk  41 , a magneto-optical disk  42 , or semiconductor memory  43  whose shape is similar to a card, stamp, sheet, stick, and the like. The CPU  22  can read data stored in these storage devices.  
     [0067]FIG. 4 shows a detailed configuration of the DVCR  3 .  
     [0068] In FIG. 4, when a user operates an operation panel  51  or a remote commander (not shown), the CPU  53  is supplied with a signal corresponding to the user operation from the operation panel  51  or an infrared ray receiving section  52 . Namely, when the user operates the remote commander, the infrared ray receiving section  52  receives an infrared ray signal indicating the user operation from the remote commander and outputs this signal to the CPU  53 . Further, the CPU  53  is supplied with control signals and various data from other devices (units) connected to the bus  2  via the bus  2  and the IEEE 1394 interface  54 .  
     [0069] Based on these signals, the CPU  53 , a major section of the controller  17 , generates, say, a control signal for controlling a VCR control section  55  and outputs this control signal to the VCR control section  55  in a VCR subunit  15  When picture data is input from other devices via the bus  2  and the IEEE 1394 interface  54 , the CPU  53  sends this data to a recording and/or reproducing signal processing section  61 . By controlling the VCR mechanical section  62  via the VCR control section  55 , the CPU  53  allows the recording and/or reproducing signal processing section  61  to record a recording signal generated from the picture data on video cassette tape (not shown) mounted in the VCR mechanical section  62 . The recording signal recorded on the video cassette tape is reproduced and is sent to the recording and/or reproducing signal processing section  61  for restoring the picture data. The CPU  53  also reads and writes the BBS in the RAM  58 .  
     [0070] The restored picture data is sent to an NTSC encoder  56  and is converted to NTSC data. The picture data is converted to an analog signal in a D/A converter  57 , and then is output to a display apparatus such as a monitor (not shown) for a display purpose. Alternatively, the picture data is sent to other networked devices via the IEEE 1394 interface  54  and the bus  2 . The monitor may be connected to the bus  2 .  
     [0071] When a video cassette tape (not shown) is mounted in the VCR mechanical section  62 , the VCR control section  55  issues to the CPU  53  a signal indicating that the video cassette tape is mounted. When receiving this signal, the CPU  53  displays a symbol or a character on the operation panel  51  for indicating a signal reception event. Alternatively, the CPU  53  turns on an LED or uses other means to notify a user that the video cassette tape is inserted in the DVCR.  
     [0072] When an antenna (not shown) receives a surface broadcast wave, a tuner  60  selects a specified channel from the received surface broadcast wave according to a control signal input from the CPU  53 . The reception signal corresponding to the selected broadcast wave is demodulated in a demodulator  59  and is sent to the recording and/or reproducing signal processing section  61  or the NTSC encoder  56 . When the reception signal is sent to the recording and/or reproducing signal processing section  61 , it is converted to a recording signal under control of the CPU  53 . The converted signal is recorded on video cassette tape (not shown) in the VCR mechanical section  62  controlled by the VCR control section  55 . The reception signal is sent to the NTSC encoder  56  and is converted to NTSC data. This signal is converted to an analog signal in the D/A converter  57 , and then is output to a display apparatus such as a monitor (not shown) for a display purpose. Alternatively, the signal is sent to other networked devices via the IEEE 1394 interface  54  and the bus  2 .  
     [0073] The controller  11  (CPU  22 ) in the IRD  1  issues a CREATE instruction for objects (to be described later). Based on this instruction, the CPU  53  (controller  17 ) executes a function for newly creating a board in the BBS, namely creating an object with a child list ID (to be described later). For executing this function, the RAM  58  stores a program according to the present invention, template data for an object with child list ID to be created (to be described later), various programs and data for DVCR  3 &#39;s operational control or computation, and the like. When the DVCR  3  is equipped with a hard disk drive, it is possible to store these programs and data in the hard disk. The program and data are read into the CPU  53  as needed. The RAM  58  is provided with registers for maintaining descriptors corresponding to the AV/C general and includes a memory space as the BBS  16 . The RAM  58  also functions as work RAM for storing data generated in accordance with program execution. The above-mentioned object, object creation, a board, a child list ID, and the like will be described in more detail below.  
     [0074] A drive  63  is connected to the CPU  53 . Like the case with the IRD  1 , the drive can be used for, say, a magnetic disk, an optical disk, a magneto-optical disk, or semiconductor memory whose shape is similar to a card, stamp, sheet, stick, and the like. The CPU  53  can read data stored in these storage devices.  
     [0075] A modem  64  is controlled by the CPU  53  and is connected to a public switching line such as a telephone line.  
     [0076] As will be described hereinafter, the present invention requires a program for implementing functions such as creating a BBS board type (to be described later) and template data for objects with child list ID to be created. For example, the program and data can be compressed and stored in built-in nonvolatile memory, hard disk, or the like in advance. It is also possible to read the program and data from the magnetic disk, optical disk, magneto-optical disk, or semiconductor memory which stores the program and data and is inserted in the drive  63 . Further, it is possible to download the program and data by means of data communication via the modem  64  such as Internet or via the IEEE 1394 interface  54 . Alternatively, the tuner  60  can be used to extract a signal for the program superimposed on a broadcast signal and stores the signal in the RAM  58 , the hard disk, and the like. When the program and data are downloaded from a network during data communication using Internet, it is necessary to enter a URL (uniform resource locator) for accessing a server which supplies the program and data. For eliminating the need for entering URLs, it may be preferable to store the pertinent URL in the RAM  58  or hard disk and automatically access the server and perform a download according to an instruction from a user or the IRD  1 .  
     [0077] The embodiment of the present invention provides the examples in which the DVCR  3  loads the program and data from Internet, the magnetic disc, optical disc, magneto-optical disc, or semiconductor memory for implementing the function such as creating board types in the BBS. The invention is not limited thereto. The IRD  1  can read the program and data from these storage devices. It is also possible to use the tuner  30  to download the program and data transmitted by data communication via the IEEE 1394 interface  54  or digital satellite communication. In this case, the program and data are temporarily stored in the RAM  37  or the hard disc, and are transferred to the DVCR  3  via the bus  2 . Then, the DVCR  3 &#39;s CPU  53  writes the program to the RAM 58  or the hard disc.  
     [0078] A board type to be newly created in the BBS is described in detail hereafter.  
     [0079]FIG. 5 shows a configuration example in a BBS block. FIG. 5 exemplifies a board type which is defined in the standard to have only one board. The board type comprises an SID (Subinit Identifier Descriptor) and an information list descriptor. There is provided only one SID in a subunit. The SID describes information about subunit capabilities and features. The information list descriptor is a board directly referenced by the corresponding SID.  
     [0080] The SID is a list specified in the AV/C general standard and is required for each subunit. When the controller first accesses the BBS, this list is read.  
     [0081] The SID contains basic information for reading and writing lists in the BBS. This information includes pointers to root lists directly linked to the BBS. They are provided as root list IDs in the SID. Namely, the SID begins with the list size and other information, followed by root list IDs. Each board type is provided with one root list ID whose value is defined in the standard officially. The root list ID specifies an information list descriptor. The controller reads a root list ID in the SID and compares it with the root list ID for an intended board type. This makes it possible to confinn whether the target BBS contains an intended board type.  
     [0082] The information list descriptor contains list information (Info List) as List_Type, has_object_ID as an attribute, List_Specific, and the number of object entries. The information list descriptor is further followed by information entry descriptors Info Entry Desc  1  to Info Entry Desc n. Each information entry descriptor comprises an object entry type (object entry type), an attribute (attribute), an object_id, and an object information specific (object info specific).  
     [0083]FIG. 6 exemplifies a board type which is capable of having a plurality of boards with the same board type. This board type comprises the SID, a board list descriptor, and an information list descriptor. The board list descriptor provides a list of a plurality of boards directly referenced by the SID. The information list descriptor indicates a board referenced from a child ID of the board list descriptor.  
     [0084] The board list descriptor is provided between the SID and the information list descriptor. The SID contains root list IDs for the board list descriptor.  
     [0085] The board list descriptor comprises List_Type as a board list, has_object_ID as an attribute, List_Specific, and the number of object entries. There are provided board entries Board Entry  1  to Board Entry n. Each board entry comprises an attribute as has_child_ID, a child list ID, and Entry specifics. The child list ID corresponds to the information list descriptor. The information list descriptor has the same configuration as in FIG. 5.  
     [0086] For example, a target device can newly create a BBS board type, namely an object with child list ID based on a CREATE instruction for objects from the controller. For implementing this, the present invention provides a configuration which allows the controller to newly add or create one BBS board type of the target device. A board type for which the controller can newly create a target device is hereafter referred to as a general board type.  
     [0087]FIG. 7 illustrates positioning of a general board type list descriptor specified by a root list ID in the SID according to the embodiment of the present invention. FIG. 7 oimts the same data structures as those in FIGS. 5 and 6 and depicts only portions needed for the description.  
     [0088] The board type list descriptor is provided between the SID and the information list descriptor or the board list descriptor. The SID contains root list IDs for the board type list descriptor. In other words, a board type list descriptor according to the embodiment of the present invention can be specified by a root list ID in the standardized SID.  
     [0089] The board type list descriptor&#39;s List_Type describes the newly defined general board type. The child list ID corresponds to the information list descriptor as in FIG. 5 or the board list descriptor as in FIG. 6. In other words, this board type list descriptor&#39;s child list ID is same as the board list descriptor&#39;s child list ID, and is capable of specifying not only the information list descriptor, but also the board list descriptor.  
     [0090] Specifically, a target device (DVCR  3  in FIG. 2) is assigned a board type list descriptor&#39;s list ID for the SID&#39;s root list ID. Initially, the target device is provided with only the board type list descriptor. When the controller sends an instruction for creating an object to the board type list descriptor, the target device creates an object with child list ID. Thereafter, the controller can add board types of any configuration in FIG. 5 or  6  by writing an ID value of the board type to be created to the child list ID.  
     [0091]FIG. 8 shows a detailed data structure of the board type list descriptor in FIG. 7.  
     [0092] In FIG. 8, descriptor_length describes a descriptor length. List_type identifies a board type list. Attributes provides the description according to the AV/C general standard. Size_of_list_specific_information describes a length of list_specific_information. List_specific_information contains detailed information about the board type list. Nunber_of_entries specifies an entry number.  
     [0093] The descriptor_length describes the length of an object entry for specifying one board type. The entry_type contains a value indicating an object entry. In this example, the entry_type describes a board type to be newly defined as an entry type. The attributes contains a value indicating that the object has a child list ID. The child_list_ID describes the list ID of the board type to be provided anew. Two high-order bytes are set to 11 16 . Two low-order bytes contain an ID using a value for the board type to be newly provided by the controller. The size_of_entry_specific_information describes the length of entry specific_information. The entry_specific_information contains detailed information about the entry. The entry_specific_information “0008 16 ” describes a board type to be created.  
     [0094]FIG. 9 shows a detailed data structure of list_specific_information in FIG. 8. When there are restrictions on the maximum number of board types which can be added anew or the entire board type list length, for example, the target device (DVCR  2 &#39;s controller  17 ) describes the associated information in the list_specific_information. The controller (IRD  1 &#39;s controller  11 ) can be provided with these restrictions in advance.  
     [0095] Non_info_block_fields_length contains the number of bytes for non info block fields. Board_type describes a value indicating the general board type. Object_list_maximum_size describes the maximum object list size of the general board. Object_entry_naximum_number contains the maximum number of object entries. Board_type_dependent_information_length contains the length of board_type_dependent_information. Board_type_dependent_information maintains information specific to the board type.  
     [0096]FIG. 10 shows an allocation table of list IDs for the BBS version 1.0. The general board according to the embodiment is indicated by one root list. A general board type value is determined in an available range of root list IDs between “1001 16 ” and “10FF 16 ”.  
     [0097]FIG. 11 shows an allocation table of list types. In this embodiment, the board type list is defined to be “82 16 ”.  
     [0098]FIG. 12 shows an allocation table of board types. In this embodiment, the general board type uses “00 16 ”.  
     [0099]FIG. 13 is a flowchart showing a flow of processing until a new board type is created in the system according to the embodiment of the present invention as shown in FIG. 2.  
     [0100] At step S 11  in FIG. 13, the IRD&#39;s controller  11  specifies the root list ID (fixed value) to “write-open” a board type to be written to the BBS  16  of the DVCR  3  as a target device. This write-open instruction is performed when the controller  11  issues a WRITE OPEN command to be described later.  
     [0101] At step S 12 , the controller  11  checks whether the controller  17  of the DVCR  3  (target device) returns an accept in response to the WRITE OPEN command. When an accept returns, control proceeds to step S 19  for performing a write operation and the like according to the standard of the board type.  
     [0102] When no accept returns from the target device (DVCR  3 ), the controller  11  performs a write-open instruction by specifing Root_List_ID for the general board type for the target device (DVCR  3 ).  
     [0103] At step S  13 , the controller  11  checks whether the controller  17  of the target device (DVCR  3 ) returns an accept in response to the WRITE OPEN command. When no accept returns, the processing terminates.  
     [0104] When the target device returns an accept in response to the write-open instruction with Root_List_ID specified for the general board type, the controller  11  reads data at the List_Specific_Information field in the BBS  16  for the DVCR  3  (target device) at step S 14 . By doing so, the controller  11  recognizes restrictions on the number of board types to be created and the total length of one board type.  
     [0105] At step S  15 , the controller  11  performs an operation (object_entries_maximum_number)-(number_of_entries(n))&gt;0 for determination. When the result is false (less than or equal to 0), the controller  11  terminates the processing. When the result is true, control proceeds to step S 17 .  
     [0106] At step S  17 , the controller  11  performs an operation (object_lists_maximum_size)−(total length of a list to be written) &gt;0 for determination. When the result is false (less than or equal to 0), the controller  11  terminates the processing. When the result is true, control proceeds to step S 18 .  
     [0107] At step S 18 , the controller  11  issues an instruction for creating an object to the board type list descriptor. This “create” instruction is performed when the controller  11  issues a CREATE command to be described later. When receiving the CREATE command, the controller  17  of the DVCR  3  (target device) creates an object with child list ID for the BBS  16 . Then, the IRD l&#39;s controller  1  writes an ID value of the board type to be created onto the corresponding child list ID. This creates a new board type. The board type creation at step S 18  will be described later in detail.  
     [0108] It is also possible to perform processing for creating a new board type in the system according to the embodiment of the present invention as shown in FIG. 2. In FIG. 14, the process at step S  13  and later processes are same as those for the example in FIG. 13. The description thereof is omitted.  
     [0109] At step S 21  in FIG. 14, the IRD l&#39;s controller  11  performs a read-open instruction for the SID in the BBS  16  of the DVCR  3  as a target device. This “read-open” instruction is performed when the controller  11  issues a CREATE command to be described later.  
     [0110] At step S 22 , the controller  11  reads all root_list_IDs from the SID, and then closes these lists. This “close” instruction is performed when the controller  11  issues a CLOSE command to be described later.  
     [0111] At step S 23 , the controller  11  checks whether a board type to be controlled is available. When such a board type is available, control proceeds to step S 19  above. When no such board type is available, control proceeds to step S 13  above.  
     [0112] The process at step S 13  and later processes are same as those described in FIG. 13.  
     [0113]FIG. 15 shows a format of the WRITE OPEN command issued from the controller  11  to a target device.  
     [0114] A WRITE OPEN command in this FIG. 15 is a type of OPEN DESCRIPTOR command used for accessing a specified address space of the target. In this WRITE OPEN command, opcode describes a value indicating an open descriptor. Operand  0  describes descriptor_type indicating a type of descriptor for write-open. Operands  1  and  2  describe list IDs to be accessed for write-open. Operand  3  describes a value indicating that the subfunction is a write-open instruction, namely opening the descriptor for read or write access. Operand  4  is reserved.  
     [0115]FIG. 16 shows a format of the READ command issued from the controller  11  to a target device.  
     [0116] In this READ command format, the first opcode describes a value indicating a read descriptor. The succeeding operand  0  describes a descriptor identifier for identifying a descriptor to be read. Read_result_status contains “FF 16 ” when a posting device issues the READ command. Alternatively, it contains a read result when the target device returns a response. Data_length describes the number of data bytes to be read from the target. When the data_length value is set to “00 16 ”, all lists are read. Address describes an address to start reading. When the address value is set to “00 16 ”, a read operation starts from the beginning.  
     [0117]FIG. 17 shows a format of the CREATE command issued from the controller  11  to a target device. FIG. 18 shows the content of the result field in FIG. 17. FIG. 19 shows the format of subfunction_ 1 _specification for subfunction_ 1 =00 16  in FIG. 17. FIG. 20 shows result field values and meanings thereof FIG. 21 shows the format of subfunction_ 1 _specification for subfunction_ 1 =01 16  in FIG. 17. FIG. 22 shows field values in FIG. 21. In FIG. 22, values “20 16  ”, “22 16 ”, and “11 16 ” are placed in the fields descriptor_identifier_where, descriptor_identified_what — 1, and descriptor_identified_what — 2 in FIG. 21, respectively. The setting of these fields means “create a new object and its child list”. When a new board type is created as described in this embodiment, the descriptor_identifier_where field in FIG. 21 describes the general board&#39;s root list ID and a value (object position) indicating which entry should be used. The descriptor_identified_what — 1 field describes a specified value for the entry type. This value is specified for a template of the board type including the child list ID. The descriptor_identified_what — 2 field describes a specified value for a template corresponding to the list type.  
     [0118] This description is provided with reference to documents such as “Enhancement to the AV/C General Specification 3.0 Version 1.0 FC2” and “TA Document  1999005  AV/C Bulletin Board Subunit General Specification 1.0 Draft 0.99:149”.  
     [0119]FIG. 23 shows a format of the CLOSE command issued from the controller  11  to a target device.  
     [0120] Basically, the CLOSE command format in FIG. 23 is same as the WRITE OPEN command format in FIG. 15. A difference is that the subfunction value in FIG. 15 indicates WRITE OPEN and the same value for the CLOSE command in FIG. 23 indicates CLOSE. The other configurations are same as those in FIG. 15.  
     [0121] The board type creation at step S  18  in FIGS. 13 and 14 will be described later in detail with reference to FIG. 24  
     [0122] In FIG. 15, the controller  11  issues a “create” descriptor of the CREATE command to the controller  17  of the DVCR  3  (target device). At this time, the create descriptor contains operands having the following values. Operand[ 0 ] describes “FF 16 ”. Operand[ 1 ] describes “01 16 ”. Operand[ 2 ] describes “FF 16 ”. Operand[ 3 ] describes descriptor type=20 16 . Operand[ 4 ] describes listID (MSB). Operand[ 5 ] describes listID (LSB). Operand[ 6 ] describes object position (MSB). Operand[ 7 ] describes object position (LSB). Operand[ 8 ] describes descriptor_type of descriptor_identifier_what — 1=22 16 . Operand[ 9 ] describes Board type entry as an object entry type. Operand[A] describes descriptor_type of descriptor_Identifier_what — 2=11 16  Operand[B] describes Information list (81 16 ) as a list type.  
     [0123] When receiving the create descriptor, the target device generates a board type entry template at the specified object position. The target device generates a list type template for the specified child list, and then returns an accept to the controller  11 .  
     [0124] The controller  11  then issues a write descriptor of the WRITE OPEN command. The controller writes a value of the board type to be generated to an entry in the general board and the board type field in the entry specific information. When the board type is a resource schedule board (RSB), the value 01 16  is written.  
     [0125] When receiving the write descriptor, the target device overwrites the board type field on the content of the specified board, say, RSB, and then returns an accept to the controller  11 .  
     [0126] The controller then issues a read descriptor of the READ command. AT this time, the controller  11  reads the child list ID in an interested entry from the general i board.  
     [0127] When receiving the read descriptor, the target device provides a child list ID and returns an accept to the controller  11 .  
     [0128] The controller  11  then issues an open descriptor for the OPEN command. At this time, the controller  11  performs a write-open instruction for the list generated through the use of the child list ID.  
     [0129] When receiving the open descriptor, the target device returns an accept to the controller  11 .  
     [0130] The controller  11  then issues a write descriptor for the WRITE OPEN command. At this time, the controller  11  specifies the board type field in the list specific information and writes the created board type.  
     [0131] When receiving the write descriptor, the target device then returns an accept to the controller  11 .  
     [0132] According to the embodiment of the present invention as mentioned above, the controller can later add a board type to a device which has a large amount of memory and the BBS, and provides networked devices with the BBS as a space for sharing information. The controller can handle, say, the most recent board type.  
     [0133] Since the embodiment of the present invention allows a board type to be added later, it is unnecessary for memory to store a complete list of board types available to devices at the time of shipment. It is possible to newly create a list of board types according to user&#39;s selection, permitting an effective use of memory.  
     [0134] According to the embodiment of the present invention, a series of processing as mentioned above can be implemented by software as well as hardware. When the software is used for performing a series of processing, a program constituting the software is installed on the controller as dedicated hardware. Alternatively, the program can be installed on a general-purpose personal computer for providing various functions.  
     [0135] As shown in FIG. 25, a general-purpose personal computer  101  includes a CPU (Central Processing Unit)  111 . The CPU  111  is connected to an input/output interface  116  via a bus  115 . A user&#39;s instruction is entered from an input section  118  comprising a keyboard, a mouse, and the like via the input/output interface  116 . According to this instruction, the CPU  111  reads a program for executing a series of the abovementioned processing from a storage medium and writes the program to RAM (Random Access Memory)  113  for execution. The storage media include ROM (Read Only Memory)  112  and a hard disc  114 , or a magnetic disc  131 , an optical disc  132 , a magneto-optical disc  133 , and semiconductor memory (not shown) mounted on a drive  120 . Programs stored in the hard disc  114  include not only preinstalled programs distributed to users, but also programs which are transferred from a satellite or a network and are received and downloaded by a communication section  119 .  
     [0136] The CPU  111  outputs a picture signal out of the processing result to a display section  117  comprising an LCD (Liquid Crystal Display), a CRT (Cathode Ray Tube), and the like via the input/output interface  116 .  
     [0137] While there have been described specific preferred embodiments of the present invention, it is to be distinctly understood that the present invention is not limited thereto but may be otherwise variously embodied within the spirit and scope of the invention. For example, according to the embodiment, there has been provided an example in which the IRD  1 &#39;s controller  11  creates a new board for the DVCR  3 &#39;s BBS  16 . It is also possible that a controller of another device or unit may create a new board for the DVCR  3 &#39;s BBS  16 .