The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 13, 1992
Filed:
Jan. 11, 1990
Robert P Ryan, Marlborough, MA (US);
Kin L Cheung, North Andover, MA (US);
Wang Laboratories, Inc., Lowell, MA (US);
Abstract
In a multi-processor virtual memory system 10 a Reference and Change Table (RCT) 36 is located upon a Memory Control Unit (MCU) 25. The RCT 36 is responsive to accesses to any of the Memory Modules (MMs) 24-26 and generates and maintains status bits indicative of the reference and change activity of all of page frames of the system memory that are accessible by any of the CPUs 12A-12n. In that each of the CPUs 12A-12n has access to the page frames of the system memory each of the CPUs 12A-12n is further 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 36. As such, the RCT provides to multiple data processors a centralized and readily accessible store of status information relating to page frames of the system memory.