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:
Mar. 08, 1994
Filed:
Apr. 19, 1991
Feng-Hsien W Shih, Yorktown Heights, NY (US);
James F Macon, Jr, Boynton Beach, FL (US);
Shauchi Ong, Pleasantville, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A least recently used cache replacement system in which the data cache is logically partitioned into two separate sections, demand and prefetch. A cache directory table and a least recently used table are used to maintain the cache. When a new demand data page is added to the cache, a most recently used (MRU) pointer is updated and points to this new page. When a prefetch page is added to the cache, the least recently used pointer of the demand section is updated with its backward pointer pointing to this new page. A cache hit on a demand of prefetch page moves that page to the top of the least recently used table. When a free page is needed in the cache, it is selected from the demand or prefetch sections of the memory based on a comparison of the demand hit density and the prefetch hit density so to maintain a balance between these two hit densities.