ACCESS REQUEST CONTROLLER IN DATA PROCESSING SYSTEM

摘要

The access request control apparatus controls access to memory apparatus via access requesting apparatus such as a channel processing unit(CHP) and CPU. A memory contol unit(MCU) determines priority between access requests simultaneously received from the requesting apparatus using a constant priority determination theory. It assigns the priority values and selects only one access request for processing. The MCU starts processing the request but redetermines priority if processing is disabled before completion. It does so by multifying the selected access request and returning it to its initial condition.