CONTROL SYSTEM FOR DISK CACHE SUBSYSTEM

PURPOSE:To recover a reading error with no intervention of an operating system by writing the same copied data into a cache memory and retrying the retrieval of the data by reading after setting the reproduction output of the data at a normal level via a magnetic disk. CONSTITUTION:When an error occurs, a copy of the information held in a cache memory is written into a magnetic disk and the search of the information is retried. For instance, a magnetic disk device 205 has such a constant reading error like the demagnetization of a magnetic disk which records magnetically data. Even in such a case, the same copied data is written into a cache memory 206 and reproduction output of the data is set at a normal level via the magnetic disk. Then the data retrieval is retried by reading. As a result, such a reading error that is not easily recovered just with the retry of a command can be recovered with no intervention of an operating system.