working set

architecture The set of all pages (in a paging virtualmemory system) used by a process during some time interval.

As a result of locality of reference, the working set

frequently consists of a relatively small fraction of a

process's total virtual memory pages. While a process's

entire working set is in physical memory the process will

run without page faults. If the working set is too large

for available physical memory, the process causes frequent

page faults.

In a multitasking environment, information about which pages

are in each process's working set allows the memory management

system to improve CPU efficiency by prepaging (also called

the working set model).

["Modern Operating Systems", Andrew S. Tanenbaum, pub.

Prentice Hall, Inc. 1992].

(1997-04-09)