Cache memory data write-back method and disk cache control device

摘要

PURPOSE:To shorten the access time by checking a record within a write range sequentially, and writing back only the record on which a write back flag is set. CONSTITUTION:The write back flag is provided in each of the records R0-R8 stored in cache memory 2a, and a back flag written on the memory 2a is set based on write access from a host device 1. Thereby, the record is managed by setting the minimum number and the maximum number of the record written at every track as the write range. When the write back to a disk device 3 is performed, the record on which the write back flag is set is written back on the disk device 3 by checking the records R0-R8 within the write range sequentially. Then, only the record written on the memory 2a is written back on the disk device 3 by performing the management of the write range with the flag. In such a manner, unrequired write back can be eliminated, and the access time when write on the disk device 3 is performed can be shortened, which enables a processing operation to be efficiently performed.