Original Publication Date: 1987-May-01
Included in the Prior Art Database: 2005-Feb-01
The algorithm described in this article is a modification of the standard clock algorithm found in the Multics system. It is a page replacement algorithm that adapts to the sequential versus localized nature of page references and achieves a greater memory hit ratio than other algorithms. It provides for the management of memory, and decides which data are to be retained for later use, and which are to be discarded to make room for other data. This algorithm is applicable to the management of a processor's main memory, and also to the management of secondary levels of a storage hierarchy (for instance a cache for a set of disk files). The criteria for judging such algorithms are: 1. The proportion of data requests which can be satisfied directly from storage (the hit ratio), and 2.