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:
Jun. 23, 1992
Filed:
Jun. 29, 1989
Frank L Perazzoli, Jr, Redmond, WA (US);
Digital Equipment Corporation, Maynard, MA (US);
Abstract
A virtual memory management system and method in which the mechanism for swapping in pages of memory in secondary storage replaces the overhead of retrieving pages from secondary storage by swapping logically contiguous clusters of pages each time that a page from secondary memory is needed. To improve the efficiency of in-page clustering, the size of the clusters which are read in are heuristically adjusted. Clustered pages are not entered into the working set until they are accessed by the process. Instead, the cluster of pages read in from secondary memory are initially entered a 'standby list' of pages which are more eligible for reallocation than pages in the working set of the process. If the process does not access a particular cluster page within a relatively short period of time of its entry onto the standby list it is reallocated by the system's memory manager. In this way, in-page cluster pages do not replace potentially more valuable pages in the working set until those pages are actually requested by the process. Depending on whether the cluster pages are used before being reallocated, cluster sizes in corresponding portions of the virtual memory space are increased or decreased.