working set
<architecture> The set of all pages (in a {paging} {virtual
memory} 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)