Setting Up Paging: Difference between revisions

A page is "not present" is one which is not (intentedintended to be) used. If the MMU finds one, it will Page Fault. Non-present pages are useful for technics such as Lazy Loading. It's also used when a page has been swapped to disk, so the Page Fault is not interpreted as an error by the OS. To the OS, it means someone needs a page it swapped to disk, so it is restored. A page fault over a page that was never swapped is a error by which the OS has a reason to kill the process.