| 摘要 |
A plurality of controllers are connected to a common bus in turn connected to a central processor. Each of the controllers respectively serves as an interface between the central processor and at least one storage unit for input/output device. In order for the controllers to distinguish between addresses, the addresses sent from the central processor contain identifier segments indicative of the controller to which the address is being sent. Controllers in turn contain programmable comparison means for comparing the identifier segments in addresses to a stored controller identifier indicative of the controller. Because the comparison means are programmable, controller identifiers have to be set up each time the system is turned on. Consequently, the present invention provides such turn on or initialization means including a read-only initialization program stored in one of the storage units: the controller interfacing with this storage unit becomes a master controller; the master controller has apparatus which is selectively activated only during initialization for accepting all addresses irrespective of the identifier segment. The other controllers have apparatus selectively activated only during initialization for disabling the comparison means and such other controllers so that no addresses are accepted by the other controllers during the initialization. In other words, the comparison means in the master controller is completely bypassed during initialization whereby the read-only initialization program is accessed only through the master controller.
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