Abstract: An architecture, a system and a method monitors data structures over an IEEE 1394-1995 serial bus network. The data structures are portions of entries posted and stored to a descriptor mechanism. A resource request is submitted by a requesting control device to an AV/C resource schedule bulletin board subunit, where request data is stored and posted. The requesting control device submits a corresponding notify command data frame to the AV/C bulletin board subunit. When a competing control device performs a specified type of access activity on a specified data structure, the bulletin board subunit sends a notify response frame to the original requesting control device. The notify response frame provides an alert to the original requesting control device that the specified access activity has been performed on the specified data structure by a competing control device.

Abstract: The invention is an architecture, a system and a method for monitoring data structures over an IEEE 1394-1995 serial bus network. The data structures are portions of entries that are posted and stored to a descriptor mechanism. Preferably, the entries are schedule entries posted and stored to an AV/C resource schedule bulletin board subunit. According to the invention, a resource request is submitted by a requesting control device to the AV/C resource schedule bulletin board subunit, where request data is stored and posted as a schedule entry. The requesting control device also submits a corresponding notify command data frame to the AV/C bulletin board subunit. The notify command frame instructs the bulletin board subunit to monitor a specified data structure within the schedule entry. Preferably, the notify command frame also specifies the type of access activity that is monitored.

Abstract: The invention is an architecture, a system and a method for monitoring data structures over an IEEE 1394-1995 serial bus network. The data structures are portions of entries that are posted and stored to a descriptor mechanism. Preferably, the entries are schedule entries posted and stored to an AV/C resource schedule bulletin board subunit. According to the invention, a resource request is submitted by a requesting control device to the AV/C resource schedule bulletin board subunit, where request data is stored and posted as a schedule entry. The requesting control device also submits a corresponding notify command data frame to the AV/C bulletin board subunit. The notify command frame instructs the bulletin board subunit to monitor a specified data structure within the schedule entry. Preferably, the notify command frame also specifies the type of access activity that is monitored.

Abstract: AV/C command and response data packets are used for asynchronous data block transactions between devices over an IEEE 1394-1995 serial bus network. Extension data fields hold extension data that support new or added features of an IEEE 1394-1995 serial bus network and devices operating therein. The AV/C data packets are encoded for the extension data fields by providing extended fields data within data fields of the Function Control Protocol (FCP) data frames. The extended fields data specifies whether or not the packet includes extension data fields, and if so, how many bytes of extension data may be included within the data field. Extension data supports device and system features such as transaction labels and error/result messages. Transaction data is used to determine the number of other extension data fields to be used during AV/C data transacted between devices and provides for the ability to establish communication protocols based on mutually supported features.

Abstract: The method and apparatus for cancelling a pending notify command of the present invention includes a mechanism which allows a controlling device to cancel a pending notify command. A controlling device has the ability to cancel a pending notify command, by sending a cancelling command to a target device while the notify command is pending. Preferably, the cancelling command is a status command. Alternatively, the cancelling command is a duplicate notify command. In a still further alternative embodiment, the cancelling command is a notify cancel command. A target device which receives a notify command from a controlling device, first sends an interim response to the controlling device. When the state of the target device changes, the target device then sends a notify response to the controlling device. Before the state of the target device changes, while the notify command is pending, if the target device receives the cancelling command, the target device then cancels the pending notify command.

Abstract: A modified AV/C command set includes status inquiry, notify inquiry and control inquiry commands. The status inquiry, notify inquiry and control inquiry commands include an opcode and any number of operands. Thus, the status inquiry, notify inquiry and control inquiry commands can include only an opcode. The status inquiry, notify inquiry and control inquiry commands are sent from a controller to a target device to determine if the target device supports a particular status, notify or control command, respectively. In response to a status inquiry, notify inquiry or control inquiry command, a target device sends a response to the controller notifying the controller as to whether or not the target device supports the particular command.

Abstract: An architecture, a system and a method monitors data structures over an IEEE 1394-1995 serial bus network. The data structures are portions of entries posted and stored to a descriptor mechanism. A resource request is submitted by a requesting control device to an AV/C resource schedule bulletin board subunit, where request data is stored and posted. The requesting control device submits a corresponding notify command data frame to the AV/C bulletin board subunit. When a competing control device performs a specified type of access activity on a specified data structure, the bulletin board subunit sends a notify response frame to the original requesting control device. The notify response frame provides an alert to the original requesting control device that the specified access activity has been performed on the specified data structure by a competing control device.

Abstract: A system comprising at least two devices coupled to a bus wherein at least one device contains a descriptor hierarchy. A data structure has a descriptor specifier which specifies an entry by a list identifier and an object identifier.

Abstract: A system and method for determining support capability of a device coupled to a bus system are described. A command is received from a device, the command requesting support capability information. The command is parsed to extract a plurality of command fields. A response is then transmitted based on the plurality of command fields extracted.

Abstract: A method and apparatus for determining the power type relationships of a unit or a subunit coupled to a high speed bus. In one embodiment, this is accomplished by a first device such as a controller sending a POWER TYPE command to a second device or target device such as a unit or a subunit. A response frame is returned from the second device to the first device indicating the power type relationships that exist.

Abstract: The invention is an architecture, a system and a method for generating and storing resource schedule entries to an AV/C resource schedule bulletin board subunit. The AV/C resource schedule bulletin board accepts and stores schedule entries posted as requests from a plurality of devices networked through an IEEE 1394 serial bus. The AV/C bulletin board provides each posted schedule entry with a status data field and a progress data field. The status data fields and progress data fields are updated periodically by the system with status values and progress values to reflect the current status and progress of the request. The status values and progress values are used to manage the resource schedule bulletin, resolve schedule conflicts, negotiate resource time between competing control devices and to provide a detailed history of each schedule entry posted to the AV/C bulleting board.

Abstract: The method and apparatus for cancelling a pending notify command of the present invention includes a mechanism which allows a controlling device to cancel a pending notify command. A controlling device has the ability to cancel a pending notify command, by sending a cancelling command to a target device while the notify command is pending. Preferably, the cancelling command is a status command. Alternatively, the cancelling command is a duplicate notify command. In a still further alternative embodiment, the cancelling command is a notify cancel command. A target device which receives a notify command from a controlling device, first sends an interim response to the controlling device. When the state of the target device changes, the target device then sends a notify response to the controlling device. Before the state of the target device changes, while the notify command is pending, if the target device receives the cancelling command, the target device then cancels the pending notify command.

Abstract: A modified AV/C command set includes status inquiry, notify inquiry and control inquiry commands. The status inquiry, notify inquiry and control inquiry commands include an opcode and any number of operands. Thus, the status inquiry, notify inquiry and control inquiry commands can include only an opcode. The status inquiry, notify inquiry and control inquiry commands are sent from a controller to a target device to determine if the target device supports a particular status, notify or control command, respectively. In response to a status inquiry, notify inquiry or control inquiry command, a target device sends a response to the controller notifying the controller as to whether or not the target device supports the particular command.