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Redundant LRU Encoding for Cache Directories

IP.com Disclosure Number: IPCOM000045995D
Original Publication Date: 1983-May-01
Included in the Prior Art Database: 2005-Feb-07

Publishing Venue

IBM

Related People

Authors:
Doyle, DE [+details]

Abstract

A technique is described for implementing a least recently used (LR replacement algorithm for two-way set associative caches which provides a number of advantages over the conventional method of using a single directory bit to indicate the usage history of each pair of cache lines. (Image Omitted) cache, a MOD bit is set in the directory, and if that line is subsequently displaced from the cache, it is written back to the main store. Cache initialization following power-up requires that each line also have a validity bit in its directory entry.