STORAGE CONTROLLER COUPLED TO STORAGE APPARATUS

摘要

A storage controller comprises a cache storage used as a cache of an external storage and a control processor coupled to the cache storage. The control processor comprises an internal access function and an external access function. The internal access function transmits a read command to the cache storage. The cache storage determines whether the read target data complying with the read command is stored in a physical storage device or not. If the result of the determination is negative, the external access function is executed while, if the result of the determination is positive, the external access function is not executed because the cache storage transmits the read target data to the internal access function without issuing a request to the external access function.