| 摘要 |
PURPOSE:To reduce the frequency of I/O access greatly by using a control means which write data only in a disk cache memory and a control means which writes data in both the disk cache memory and a disk device optionally and selectively. CONSTITUTION:A command from a CPU is supplied to a command analyzing part 11, which identifies a READ command, WRITE, command or WRITEx command and actuates one of three processing blocks 13-15. An WRITE command processing block 14 attains I/O access to a disk device 6 for the updata of the corresponding block in prallel to record writing to the disk cache memory 5. The WRITEx command processing block 15 writes a record in the disk cache memory 5, but does not perform update processing for the disk device 6. Two commands are used properly for the purpose to reduce the frequency of I/O access greatly. |
