摘要 |
The present invention has as an object thereof to efficiently execute a plurality of I/O commands in a secondary storage device. The tags of the I/O commands which are issued from a data processing device to a secondary storage device comprise the tag A part and the tag B part. The same value is attached as the tag A part to a group of I/O commands which are to be executed in a continuous manner. Values of the tag B parts are provided in order to distinguish I/O commands having the same value of the tag A part. In the secondary storage device, when an I/O command is received from the data processing device, when it is shown by the tag B part that the I/O command is the first command in an I/O command group, or alternatively, when an I/O command having the same tag A part value is not stored in the queue, the I/O command received is added to the final end of the queue. On the other hand, when an I/O command having the same tag A part value is stored in the queue, the I/O command received is inserted after the I/O command group having the same tag A part.
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