Patent ID: 8009378

Claim:
A storage device comprising: a disk storage medium; a cache memory configured to store data read from the disk storage medium; a cache control module configured to determine whether data, which is designated by a media access command from a host device, is stored in the cache memory, and to selectively access the cache memory and the disk storage medium in accordance with a result of the determination; and a power management module configured to have a first mode of stopping rotation of the disk storage medium on condition that a media access command is not received during a predetermined time from last reception of a media access command, and a second mode of stopping the rotation of the disk storage medium on condition that a media access command which causes access to the disk storage medium is not received during a predetermined time from last reception of a media access command which causes access to the disk storage medium, to execute a process of stopping the rotation of the disk storage medium by using one of the first mode and the second mode, which is selected in accordance with a request from the host device, to have a third mode of starting the rotation of the disk storage medium on condition that a media access command is received in a state in which the rotation of the disk storage medium is stopped, and a fourth mode of starting the rotation of the disk storage medium on condition that a media access command which causes access to the disk storage medium is received in a state in which the rotation of the disk storage medium is stopped, and to execute a process of starting the rotation of the disk storage medium by using one of the third mode and the fourth mode, which is selected in accordance with a request from the host device.