Wednesday, June 15, 2011

Paging in Windows

Windows uses demand paging algorithm to load pages in the memory. It also use cluster loading so that some of the adjacent pages are also loaded along with it (assuming that the Process would request for them sooner).

Windows have also build up some prefetcher which facilitate preloading various pages which it thinks would be used in the coming time. Prefetcher take this decision based on the usage history it has collected with time. It actually adjust priority of different pages to affect their loading behavior.

When prefetcher instigate loading of pages, the Pages get loaded and added to the Standby list. So whenever later, a Process or the System need to refer those pages, the Pages are transfered to the Working set using an inexpensive Soft page fault.

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