Patent ID: 6058436
Filing Date: 2000-05-02
Classification: G06F

Abstract:
In an SCSI protocol in which peripheral devices arbitrate for control of an SCSI bus in order to communicate with a communication partner, a method for reducing arbitration, selection and reselection overhead, wherein a current target device is allowed to control transfer of bus ownership when the target device has completed a current task and is ready to release the bus, the method comprising:configuring a device as a quick arbitration and select (QAS) capable device, such that QAS capable devices evaluate the contents of the SCSI bus during MESSAGE-IN phases in order to detect a QAS message code;configuring a current target device to assert a QAS message code during a message-in phase;placing target SCSI IDs onto the SCSI bus at the detection of a QAS message code, by all QAS capable devices;evaluating SCSI IDs on the SCSI bus by the current target device, the current target device driving a new arbitration winner SCSI ID onto the bus;deasserting a message-in phase signal by the current target device; andasserting SEL by the arbitration winning device, the winning device further asserting its own SCSI ID and the SCSI ID of its desired communication partner onto the SCSI bus.