DISK CACHE CONTROL SYSTEM

PURPOSE:To permit even a magnetic disk which does not have a cache function to inexpensively obtain the cache function without providing a private hardware by comparing the contents of a starting parameter with a cache control table when the number of starts is less than a prescribed value. CONSTITUTION:When the number of starts is larger than a prescribed value, regular data transfer is executed, namely, data only for the number of starts are read out of the magnetic disk 4 and they are transferred to the user area of a main storage device 2. When the number of starts is less than the prescribed value, a system shifts to a cache control processing. When data for the number of starts are previously stored in a cache area in a hardware-only area from a start address, data stored in the cache area is transferred and stored in the user area. When it is not stored in the cache area, data for the number of starts are transferred and stored in the user area from the start address, and data only for the number of succeeding starts are transferred and stored in the cache area in the hardware-only area as look-ahead data.