Data multiprocessing system having protection against lockout of shared data

摘要

A data multiprocessing system has use-status word control circuitry for managing the exclusive use by individual processors one at a time of the common data resources of a shared main memory unit. To avoid the "system down" that occurs when a processor having exclusive use of such a common resource becomes inoperative, the control circuits of a still operative processor seeking to use that common resource will set the use-status words associated with the common resource back to a usable state thereby permitting that resource to be used by the operative processor.