| 摘要 |
PURPOSE:To reduce the generation of overruns by replacing a counter of a microprogram for each generation of the overrun of a sector and setting again the set sector position through a set sector processing part. CONSTITUTION:When a controller 2 receives an instruction to give an access to a disk 3 for read or write from an upper device 1, a microprogram 4 of the controller 2 decides the address of a desired sector and sets a set sector number (n-2) for interruption of rotational position sensing RPS. The set sector number is temporarily separated from the device 1. Then the RPS interruption is produced when the position of the set sector is detected. If the time during which the transfer of data equal to a sector is through between the device 1 and the controller 2 is larger than the time needed to travel two sectors, a sector overrun is produced. Thus a counter 5 of the program 4 is replaced. When the count value of the counter 5 exceeds the prescribed value, a set sector processing part 6 sets again the set sector position. Thus the generation of overruns can be reduced.
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