| 摘要 |
PURPOSE:To attain a reliable data write without giving a burden to a host device by comparing write data read out from a buffer means and a disk storage medium and rewriting the write data stored in the buffer means into the disk storage medium when these read data do not coincide. CONSTITUTION:The first read data DMDB from a buffer memory 6 is set in a register 82 for the standby. Read data RD by one byte stored in a shift register 92 at an FDC9 is transferred to a buffer register 91 and a DMAC7 transfers it to a register 81 of a comparator circuit 8. Then the read data RD by a prescribed byte number and a write data stored in the buffer memory 6 are compared, and when they are coincident (when CERF is at low level), the end of normal write is informed to the host side and when dissidence takes place, whether or not the write retrial for a prescribed number of times is executed is discriminated. When the number of times is not reached, the preceding step is resored and when the retrial number of times, is reached, the generation of write error is informed to the host side.
|
