IEEE Std 1394.3:2003 pdf free download

IEEE Std 1394.3:2003 pdf free download

IEEE Std 1394.3:2003 pdf free download.IEEE Standard for a High Performance Serial Bus Peer-to-Peer Data Transport Protocol (PPDT).
Just as either initiator or target may establish a connection, either may terminate the connection regardless of which one created the connection. A disconnect may be synchronized with the transport flow in order to gracefully end the connection or it may preempt the transport flow if necessary. Once the disconnect is complete. the target resources (queue numbers and task slots) are available for reuse.
4.4 Data transfer between initiator and target
Once a connection is established, application data may be transferred between initiator and target. SBP-2 transport flow ORBs are used to regulate the data transfer: each ORB specifies the direction (from the target or to the target) and provides a buffer in system memory that is either the source or destination for the data. The target initiates all data transfer requests, which permits it to pace the data transfer rate according to the availability of its own resources. The initiator, on the other hand, makes alt of the data (or a buffer to accommodate all of the data) accessible the whole time the ORB is active.
Data transfer from the initiator to the target is straightforward: the initiator signals an ORB with the appropriate direction bit to the target and the target issues read requests to access the data. Data transfer in the opposite direction, from the target to the initiator, is more complex. Because the target cannot signal an ORB to the initiator, it indicates to the initiator that data is available. LTnlcss the initiator had anticipated data transfer from the target and already signaled an ORB, the initiator signals an ORB with an empty buffer to receive the data and the target issues write requests to store the data.
In both cases. ORB completion is indicated when the target scores a status block at the initiator. The status block specifies a residual count that indicates the quantity of data transferred. The status block also includes codes that describe successful or error completion of the data transfer described by the ORB. The status block does not indicate whether or not the data was successfully utilized by an application client or service—only whether or not the data was transferred across Serial Bus.
Data transfer between initiator and target is modeled either as a datagram or as a stream. When datagram mode is used, each service data unit (SDU) fits within a single buffer described by an ORB. If no SDU is available for transfer. the ORB may block and not be completed until an entire SDLJ is ready. Or. if the recipient is unable to accept the SDU (too small a butler), no data is transferred and an error results. In contrast. stream mode permits data to flow as it becomes available. An ORB that transfers data to a target in stream mode cannot fail because the target’s butler is too small while an ORB that transfers stream data from a target may complete as soon as the first byte of data is available.6 In both cases—datagram and stream—circumstances may arise where ORBs are completed even though no data has been transferred.