| 摘要 |
PURPOSE:To lighten the burden to a processor and a high rank controller, by providing an active switch and an interface switch on a control part, and switching the control part in accordance with a control state from other interface. CONSTITUTION:An instruction for selecting a controller from high rank controllers 4, 5 is set to selecting circuits 30-33 by receivers 20-23, and the circuits 30-33 set interface switches 34, 35. Also, by the switches 34, 35, realization of selection is reported to the high rank controllers 4, 5 through drivers 36-39. In this case, by an active switch 28, it is stored that one controller has become an active state, and by an active switch 29, it is stored that the other controller has become an inactive state. In this state, the controller is switched in accordance with a control state from other interface, by which the burden to the processor and the high rank controller is lightened. |
