CENTRALIZED REFERENCE AND CHANGE TABLE FOR A MULTIPROCESSOR VIRTUAL MEMORY SYSTEM

摘要

In a multiprocessor virtual memory system (10) a Reference and Change Table (RCT) (36) is located upon a Memory Control Unit (MCU) (25). The RCT is responsive to memory accesses to generate and maintain status bits indicative of the reference and change activity of all page frames of the system memory that are accessible by any of a plurality of CPUs (12A-12n). Each of the CPUs has access to the page frames of the system memory and each is enabled, via privileged instructions, to test (read) and reset (clear) over a system bus (16) the memory page frame status bits that are generated and stored by the RCT. Thus, the RCT provides to multiple data processors a centralized and readily accessible store of status information relating to page frames of the system memory.