A peripheral device in which many optical disks (usually in cartridges) are stored in slots in a storage rack. The device contains one or more optical disk drives; any disk can be taken from its slot and loaded into a drive by a picker mechanism, at the command of the host computer. The picker can also return a disk to its slot, turn a disk over (if the drive can only read one side), and move a disk to or from a drawer where it can be reached by the operator. Standard disks and cartridges are used.