Electrical computers and digital data processing systems: input/ – Input/output data processing – Input/output command process
Reexamination Certificate
1999-03-16
2003-02-11
Lee, Thomas (Department: 2182)
Electrical computers and digital data processing systems: input/
Input/output data processing
Input/output command process
C710S020000, C710S030000
Reexamination Certificate
active
06519656
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a data transmission apparatus and a method thereof for sending and receiving data recorded on a recording medium such as an optical disk, magnetic tape and the like, to and from an external equipment via a digital interface such as IEEE 1394 Standard, using a command adapted thereto.
2. Description of the Prior Art
Recently, usage of IEEE 1394 Standard has been increased in a serial data transmission system. The IEEE 1394 system can be used not only for transmission of computer data which is conventionally conducted by a SCSI system or the like, but also used for transmission of substantive audio and/or video (referred to as “AV”, hereinafter) data to be processed by an AV equipment. This is because the IEEE 1394 system has two communication methods defined therein, i.e., an isochronous data transmission system and an asynchronous data transmission system.
The isochronous communication is a data transmission method which can be used for transmitting data, such as substantive AV data, requiring a real time property. In this method, a frequency band required for the data transmission is previously obtained prior to the start of the data transmission, and then the data transmission is conducted using the band. By this arrangement, the real time property of the data transmission can be assured.
Meanwhile, the asynchronous communication is a data transmission method using a free time for transmitting auxiliary data such as command or computer data and the like data which does not require a real time property. This communication method can be regarded as equivalent to a conventional SCSI method.
Various standards are proposed as a host transmission protocol on the IEEE 1394 system, and IPC 61883 standard is used as one of the methods. The IEC 61883 standard specifies such as a method of sending and receiving AV data requiring real time property in an isochronous communication system, and also specifies a method of sending and receiving a command to be given to an AV equipment in an asynchronous communication system.
A set of AVIC commands and responses are transported by Function Control Protocol (FCP) defined by IEC 61883. FCP provides a simple means to encapsulate commands and responses within IEEE 1394. The scope of the present invention field is within the AV/C commands and responses defined by IEC 61883. The format of an FCP frame encapsulated within a Serial Bus block packet is shown in FIG.
8
.
As shown in
FIG. 8
, the format of FCP frame is encapsulated within a Serial Bus packet where one rank i.e. one quadrate corresponds to 32 bits and the first five ranks (i.e., first five quadrates) are used as a header of a packet in the asynchronous system on IEEE 1394 Standard, and the following “cts” and FCP data fields are subsequently transmitted. In this format, destination ID, source ID, and the like fields are defined where the cts field defines the command transaction format used by the FCP frame. Commands originated by a device at a serial bus node (i.e., a controller) are addressed to the FCP COMMAND register (i.e., destination_offset) at the serial bus node that contains the device to be controlled (i.e., the target). The data payload of both FCP request and response packets, specified by data_length, is limited to a maximum of 512 bytes.
FIG. 9
shows a structure of an AV/C command frame which is up to 512 bytes of command payload. The AV/C commands and responses are encapsulated within FCP frames and are transmitted between the controller and target FCP_COMMAND and FCP_RESPONSE registers. In this command frame structure, a “ctype” l field is defined for indicating a command type as to whether the command is a control one or an inquiring one. The subunit_type and subunit_ID fields are defined for identifying a type of an AV equipment and the subsequent opcode and operands [0] to [n] indicate an actual command such as PLAY, STOP, RECORD and the like. All of the operands are optional and defined by ctype, subunit_type and opcode.
In the case where a compact disk or mini disk is used as a data recording medium in a disk drive unit for recording and reproducing substantive data such as, for example, audio (and/or video) data, the disk is also provided with auxiliary attributive information as well as the substantive audio (and/or video) data recorded thereon.
As shown in
FIG. 10
, the attributive information is recorded in a TOC (Table-Of-Contents) region of a compact disk or in a UTOC region of a mini disk.
In the case of audio data such as music recorded in a disk, the attributive information includes a start address and end address of the music data, title of music, recorded date/time of the music data and the like information. There is no defined method of transmitting such attributive information in the serial data transmission on the EEC 61883 standard. Therefore, in the conventional data transmission system, there are proposed a method of storing the attributive information in a data format of a list structure and a method of accessing the listed attributive information from an external equipment.
FIG. 11
shows an example of the conventional data transmission system of storing and accessing the listed attributive information. In this example, a data transmission apparatus
1000
having, e.g., an optical disk
1004
loaded therein is electrically connected to an external equipment
1001
via a digital interface
1002
, where the optical disk
1004
is provided with substantive AV data and attributive information data of the AV data recorded thereon. The attributive data includes data number of the AV data (which indicates the number of musics when the AV data is music audio data), total reproduction time, reproduction time of individual AV data, title of the disk, titles of AV data, and the like.
When the optical disk
1004
is loaded on the apparatus
1000
, the attributive information such as data number of the AV data, total reproduction time, reproduction time of each AV data, each title and the like data are reproduced and stored as an attributive information list illustrated as a first list
1003
in a register storage portion of the apparatus.
Meanwhile, status information indicating the present operation status of the apparatus
1000
such as reproduction or stop and the like, present reproduction position, present reproduction method such as normal reproduction or program reproduction and the like, are stored as a status information list illustrated as a second list
1005
in the register storage portion of the apparatus.
FIG. 12
shows a conventional example of a concrete data pattern format construction of the attributive information list
1003
having a structure of three class layers. In the first layer structure, a packet header is positioned at the top and the attributive information groups of the AV data (illustrated as first, second, third musics . . . ) are arranged below in turn. In the second layer structure, the packet header is comprised of header length indicating a specified byte length of the header and the entire attributive information contained in the disk while the attributive information group of each AV data is comprised of a data header including a data length and attributive information contents of each AV data.
As shown in the third layer structure, the entire disk attributive information is comprised of information blocks including an entire reproduction time, title of the disk, number of musics and the like, each having a specified byte length of e.g. four bytes while the attributive information contents of each AV data includes a reproduction time, title and the like of each AV data, each content having a data length of a specified bytes number.
On paying attention to the third stair layer structure of the data pattern format shown in
FIG. 12
, when an attributive information content such as, for example, a specific title of music, is desired to be accessed, the accessing must be conducted by designating the address positio
Kondo Satoshi
Muraki Kenji
Yamada Jiro
Cao Chun
Lee Thomas
Matsushita Electric - Industrial Co., Ltd.
Wenderoth , Lind & Ponack, L.L.P.
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