Importance

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Abstract

A central sub-system of a data processing system, including an operator console controlling a service processor, is divided into several sub-units, functioning separately from each other. The sub-units include processors that are connected together and to a common controller for a common memory unit by data, address and control buses. Each sub-unit includes a configuration device that stores an appurtenance indicator derived from the service processor in response to sub-unit initialization, and enables its associated sub-unit to exchange data with the memory unit. The sub-unit having the highest priority of the sub-units attempting to access the memory units is connected to the memory unit by the controller. A single configuration memory stores an indication of the sub-units in service in the central sub-system. The configuration memory is addressed each time the memory unit is addressed by a signal indicative of the appurtenance indicator derived from the selected sub-unit. The configuration memory derives an authorization signal that commands performance of memory cycles by the selected unit when the configuration memory contains an indication that the selected sub-unit is in service in the sub-system. The controller includes memorization means for storing the highest priority sub-unit trying to access the memory unit. The memorization means derives an output that is coupled to the data address and control buses to transmit a signal indicative of the number of the sub-unit with data to be exchanged with the memory unit to each of the authorizing means, thereby to establish data transmission between the sub-unit having the highest priority and the memory unit.

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First Claim