CHANGER

Prior to the control of disk transportation, from each of plural incorporated disk drives, a changer controller acquires an identifier peculiar to the disk drive via a local bus line, and recognizes correspondence relationships between element addresses and the disk drives. In response to arrival of a first request command, the recognized correspondence relationships are sent to a computer system serving as the request source. Furthermore, in response to arrival of a second command, also each of the disk drives sends the identifier to the computer system serving as the request source via the SCSI controller.