| 摘要 |
A buffer memory is prepared to temporarily store data sequentially read out from consecutive storage positions of a magnetic disk. When a read request is received from a host system, and an HDC reads out the requested data from the magnetic disk, the readout data is written in a buffer area in the buffer memory, which is assigned by a CPU and designated by a buffer management data portion, from the start position to the end position of the area. If the requested data exceeds the capacity of this area, the start address returns to a position indicated by a new start buffer address set in the buffer management data portion which is set by the CPU, e.g., a middle point in the buffer area, and the succeeding readout data is stored in the buffer area from the middle point to the end position. The requested data stored in the buffer memory is sequentially transferred to the host system. In the area extending from the start address, set in the buffer management data portion, to the end position, an area from which data is transferred to the host system is recognized as a free area, and succeeding data is sequentially stored therein by the HDC.
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