摘要 |
PURPOSE:To speed up the fetch of an alternate destination address, compared with the case that it is read out from a disk plate by storing the alternate destination address in a ROM. CONSTITUTION:An alternate sector detecting part 8 always monitors a sector address information B, and when it detects that this sector address information B is previously registered in an alternate information ROM 9, it gives an alternate sector detection signal E to a read/write control part 7. The read/write control part 7 immediately finishes an ordinary read/write operation in progress and gives the information F for reading/writing the alternate destination sector address, to a data read/write control part 6, and the data read/write control part 6 reads out the alternate destination sector address H by using a write/read head 4, and transmits an alternate sect address I to the read/write control part 7. Thus, the speed-up of the fetch of the alternate destination address can be realized.
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