PURPOSE: To omit a device cross call interface circuit to be connected between adaptors by incorporating a means accumulating control information necessary for reserve/release into a control circuit connected to each peripheral device.

CONSTITUTION: Assign latch circuits 8-1, 9-1, device end latch circuits 8-2, 9-2 and back change latch circuits 8-3, 9-3 are respectively built in logical control circuits 8, 9 connected so as to correspond to a magnetic disc device 5' each other. Various registers such as cylinder address registers, head address registers and difference registers are previously incorporated in the logical control circuits 8, 9 respectively and the status information required for reserve and release are stored in these registers, so that it is unnecessary to connect a device cross call interface circuit between adaptors 3', 4'.