| 摘要 |
Where a command having a selection waiting phase unifies standard operations to take place in different SCSI phases, if an SCSI controller is selected before the command is issued, the command issued will be disregarded. The problem of the command being disregarded is solved by the provision of a circuit which responds only when the command of performing select wait is issued. The circuit detects the issuance of the command of performing select wait to the SCSI controller and outputs an detection signal indicative of such fact. The SCSI controller is adapted to respond only when the detection signal is active. Since the command of performing select wait can be used regardless of its issuing timing, the overhead time can be reduced greatly as compared with the arrangement where a command of performing processing is used in each phase.
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