Abstract: According to one embodiment, a serial ATA interface apparatus having an S-ATA bridge. The S-ATA bridge is to be connected to a host system by a serial ATA bus. The S-ATA bridge has a shadow register and a buffer memory. The shadow register stores commands. The buffer memory can access a HDC. The S-ATA bridge finishes processing the commands before it outputs a response signal to the host system.

Abstract: According to one embodiment, an interface device, which is configured to be mountable in a storage device, includes a first serial interface which executes communication with a host, a second serial interface which executes communication with an external device, a unit which calculates a total storage capacity by adding a storage capacity of the storage device to a storage capacity of the external device, and informs the host of the total storage capacity, an address decoder which determines whether an address value included in an access command from the host belongs to address range which is to be assigned to the storage device, and a unit which sends an access command to a data storage unit within the storage device if the address value belongs to the address range, and transmits the access command to the external device if the address value does not belong to the address range.

Abstract: A disk drive is disclosed which has a copying function to copy data which is recorded on its disk medium onto a copying destination disk drive as an external device. Upon receipt of a copying operation command from an operated switch, a communication link is established to the copying destination disk drive. The disk drive transfers read-out data from the disk medium as well as a write command to the copying destination disk drive.