Abstract: Methods and systems are provided for Reducing Write I/O Latency Using Asynchronous Fibre Channel Exchange. A FCP target device may send one or more FC write control information units (IUs) to a FCP initiator device within a first FC exchange to request a transfer of data associated with a FCP write command IU previously sent to the FCP target device by the FCP initiator device within a second FC exchange. The FC write control IUs may be sent without the FCP target device first receiving from the FCP initiator device a sequence initiative of the second FC exchange, and/or may be sent within the first FC exchange concurrently with the FCP initiator device sending one or more FCP data IU sequences within the second FC exchange to the FCP target device. Thus, a full-duplex communication environment may be setup between the FCP initiator device and FCP target device.

Abstract: A FCP initiator sends a FCP write command to a FCP target within a second FC Exchange, and the target sends one or more FC write control IUs to the initiator within a first FC Exchange to request a transfer of data associated with the write command. The first and second FC exchanges are distinct from one another. A payload of each write control IU includes an OX_ID value with which the initiator originated the second Exchange and a RX_ID value assigned by the FCP target for the second exchange. The two Exchanges yield a full-duplex communication environment between the initiator and target that enables the reduction or elimination of latencies incurred in a conventional FCP write I/O operation due to the half-duplex nature of a single FC Exchange. The write control IU may be an enhanced FCP_XFER_RDY IU or a new FC IU previously undefined by the FCP standard.

Abstract: A FCP initiator sends a FCP write command to a FCP target within a second FC Exchange, and the target sends one or more FC write control IUs to the initiator within a first FC Exchange to request a transfer of data associated with the write command. The first and second FC exchanges are distinct from one another. A payload of each write control IU includes an OX_ID value with which the initiator originated the second Exchange and a RX_ID value assigned by the FCP target for the second exchange. The two Exchanges yield a full-duplex communication environment between the initiator and target that enables the reduction or elimination of latencies incurred in a conventional FCP write I/O operation due to the half-duplex nature of a single FC Exchange. The write control IU may be an enhanced FCP_XFER_RDY IU or a new FC IU previously undefined by the FCP standard.

Abstract: The invention, in its various aspects and embodiments, includes a method for uniquely identifying a device on a SCSI bus. The method first queries the device with a first SCSI command to obtain general identification information. Next, a first set of identification information for the device is extracted from the general identification information. A second SCSI command is then determined from the first set of identification information. Next, the device is queried with the second SCSI command to obtain general device identifiers. A second set of identification information for the device is then extracted from the general device identifiers. Then, an unique identifier is formulated from the first and second sets of information.