STORAGE CONTROLLER

PURPOSE:To improve the throughput of a host computer by increasing the hit rate of a cache while performing data transfer between a disk storage device such as an HDD and the host computer at a high speed. CONSTITUTION:The storage controller 1 which is interposed between the host computer 100 and disk storage device 200 and controls the data transfer between the both is provided with a 1st buffer memory 4 which stores transfer data in the unit of sector and a 2nd buffer memory 7 which forms the cache memory. Consequently, while a large amount of data are transferred between the external storage device 200 such as the HDD and the host 100 at a high speed, the hit rate of the cache is increased to improve the throughput of the host 100.