Patent attributes
Embodiments of the invention allow cache control optimized for the processing characteristics of application programs, and thus improve data transfer efficiency. In one embodiment, a disk device includes a disk; a cache for temporarily saving data that was read in from the disk, and data that was transferred from a host; and a controller for controlling data transfer between the cache and the host and between the cache and the disk; in which an independent cache area is set for each command type for application programs each different in data-processing policy can be set in the cache, and efficient read-ahead that utilizes the accessibility of the application programs each different in data-processing policy, can be realized by controlling the manner of read-ahead for each command type.