| 摘要 |
PURPOSE:To minimize the time required for the scanning of logic numbers by adding a first-in first-out hard queue, where a logic number and a state number are stored when the state is changed in this logic number, to each interface part. CONSTITUTION:when one of logic numbers 1-n is set to the data transfer request state, a control circuit 200 sets the data transfer request to a state management area corresponding to a subchannel as the state number and stores the logic number and the state number in the hard queue of a pertinent interface part and transfers the control to an execution request detection processing. In the execution request detection processing, the control part scans the hard queues of individual interface part; and if the storage of the logic number and the state number in the hard queue is confirmed in this scanning, the control part stops scanning and takes out the logic number and the logic state from the hard queue and compares this state number with the state number in the state management area of the subchannel indicated by the logic number, and the data transfer start processing is performed if they coincide with each other and the state number indicates the data transfer request.
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