Communication control apparatus and method

• US 20030005106A1
• Filed: 06/28/2002
• Published: 01/02/2003
• Est. Priority Date: 10/31/2000
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Isoda, Takashi
• Granted Patent: US 7,363,405 B2
• Time in Patent Office: Days
• US Class Current: 709/223
• CPC Class Codes: H04L 12/40123 Interconnection of computers and peripherals printer information exchange with computer G06F3/1293
• CPC Class Codes: H04L 12/6418 Hybrid transport

Abstract

An initiator has logical devices A, B and C. In the directory structure of the config ROM showing the unit structure, instance directories A, B and C are made; initiator unit directories 1, 2, and 3 are made under the respective instance directories A, B and C; and feature directories showing the functions provided by the respective logical devices are made under the initiator unit directories 1, 2, and 3. This structure allows the functions available from the initiator to be shown and allows the available functions to be known to another node such as a target device.

Claims

1. A communication control apparatus in which data in a memory of a device can be directly read by another connected device via a communication line by designating an address of the data, and the devices are connected to each other by communication means, characterized in that

a function providable by the device is readably stored via the communication line, and at least two attributes depending on a communication protocol ability of the communication means are stored.

2. The communication control apparatus according to claim 1, characterized in that when at least two attributes depending on the communication protocol ability are to be described in a device which adopts a protocol which does not allow describing in each device at least two attributes depending on the communication protocol ability, said at least two device attributes depending on the communication protocol ability can be described using some of items which express communication protocol attributes stored in the storage means.

3. The communication control apparatus according to claim 2, characterized in that when IEEE 1394.3 is used as the communication protocol and a role thereof is an initiator, a version item in a unit directory defined by IEEE 1212R is utilized as an attribute item which enables describing said at least two device attributes depending on the communication protocol ability.

4. The communication control apparatus according to claim 3, characterized in that when a plurality of attributes depend on the communication protocol, the unit directory which expresses the attributes depending on the communication protocol is permitted to have only one unit directory which describes all items including the version item in accordance with an IEEE 1394.3 definition, and a unit directory which expresses an attribute other than the attributes is permitted to have one or a plurality of unit directories in which only the version item has a specific value different from the IEEE 1394.3 definition and another item complies with the IEEE 1394.3 definition.

5. The communication control apparatus according to claim 4, characterized in that a unit directory which corresponds to only one attribute depending on the communication protocol and can communicate with a target complying with IEEE 1394.3 is described including a version item in accordance with the IEEE 1394.3 definition, and another attribute is described by a unit directory in which only the version item has a specific value different from the IEEE 1394.3 definition and another item complies with the IEEE 1394.3 definition.

6. A computer program which uses a computer which is connected to another device by communication means and can directly read data in a memory from said another device by designating an address of the data, wherein the computer program realizes readably storing a function providable by the computer via the communication line, and storing at least two attributes depending on a communication protocol ability of the communication means.

7. The computer program according to claim 6, characterized in that when at least two attributes depending on the communication protocol ability are to be described in a computer which adopts a protocol which does not allow describing in each device at least two attributes depending on the communication protocol ability, said at least two device attributes depending on the communication protocol ability can be described using some of items which express communication protocol attributes stored in the storage means.

8. The computer program according to claim 7, characterized in that when IEEE 1394.3 is used as the communication protocol and a role thereof is an initiator, a version item in a unit directory defined by IEEE 1212R is utilized as an attribute item which enables describing said at least two device attributes depending on the communication protocol ability.

9. The computer program according to claim 8, characterized in that when a plurality of attributes depend on the communication protocol, the unit directory which expresses the attributes depending on the communication protocol is permitted to have only one unit directory which describes all items including the version item in accordance with an IEEE 1394.3 definition, and a unit directory which expresses an attribute other than the attributes is permitted to have one or a plurality of unit directories in which only the version item has a specific value different from the IEEE 1394.3 definition and another item complies with the IEEE 1394.3 definition.

10. The computer program according to claim 9, characterized in that a unit directory which corresponds to only one attribute depending on the communication protocol and can communicate with a target complying with IEEE 1394.3 is described including a version item in accordance with the IEEE 1394.3 definition, and another attribute is described by a unit directory in which only the version item has a specific value different from the IEEE 1394.3 definition and another item complies with the IEEE 1394.3 definition.

12. A computer-readable memory characterized by storing in a computer the computer program defined in any one of claims 6 to 10.

11. A communication control method in a communication control apparatus in which data in a memory of a device can be directly read by another connected device via a communication line by designating an address of the data, and the devices are connected to each other by communication means, characterized in that

a function providable by the device is readably stored via the communication line, and at least two attributes depending on a communication protocol ability of the communication means are stored.

13. A communication control apparatus for providing a service requested of a device connected via a communication line, characterized by comprising:

a plurality of service providing devices; and

storage means for storing pieces of information about services provided by said plurality of service providing devices so as to enable reading the pieces of information by another device via the communication line,

wherein the pieces of information about the services are constituted by a hierarchical tree structure for each of said plurality of service providing devices.

14. A communication control method for providing a service requested of a device connected via a communication line, characterized by comprising

storing, in storage means, pieces of information about services provided by a plurality of service providing devices so as to enable reading the pieces of information by another device via the communication line,

wherein the pieces of information about the services are constituted by a hierarchical tree structure for each of the plurality of service providing devices.

15. A computer program for causing a computer to provide a service requested of a device connected via a communication line, characterized by realizing

storage means for storing pieces of information about services provided by a plurality of service providing devices so as to enable reading the pieces of information by another device via the communication line,

wherein the pieces of information about the services are constituted by a hierarchical tree structure for each of the plurality of service providing devices.

16. A computer-readable memory characterized by storing in a computer the computer program defined in claim 15.