Editing Demand paging (section)

{{Short description|Method of virtual memory management}}
{{No footnotes|date=June 2009}}
In [[computer]] [[operating system]]s, '''demand paging''' (as opposed to [[anticipatory paging]]) is a method of [[virtual memory]] management. In a system that uses demand paging, the operating system copies a disk [[paging|page]] into physical memory only when an attempt is made to access it and that page is not already in memory (''i.e.'', if a [[page fault]] occurs). It follows that a [[process (computing)|process]] begins execution with none of its pages in physical memory, and triggers many page faults until most of its [[working set]] of pages are present in physical memory. This is an example of a [[lazy loading]] technique.