Page Fault

A page fault (sometimes #pf or pf) is a trap to the software raised by the hardware when a program accesses a page that is mapped in the virtual address space, but not loaded in physical memory. In the typical case the operating system tries to handle the page fault by making the required page accessible at a location in physical memory or kills the program in the case of an illegal access. The hardware that detects a page fault is the memory management unit in a processor. The exception handling software that handles the page fault is generally part of the operating system.

Contrary to what the name 'page fault' might suggest, page faults are not always errors and are common and necessary to increase the amount of memory available to programs in any operating system that utilizes virtual memory, including Microsoft Windows, Unix-like systems (including Mac OS X, Linux, *BSD, Solaris, AIX, and HP-UX), and z/OS. Microsoft uses the term hard fault in more recent versions of the Resource Monitor (e.g., Windows Vista) to mean 'page fault'.

Read more about Page Fault:  Handling Illegal Accesses and Invalid Page Faults, Performance

Other articles related to "page fault, page faults, pages, page, fault, faults":

Page Fault - Performance
... Page faults, by their very nature, degrade the performance of a program or operating system and in the degenerate case can cause thrashing ... to programs and the operating system that reduce the number of page faults improve the performance of the program or even the entire system ... Generally, making more physical memory available also reduces page faults ...
Swapspace - Overview
... of paging are performed when a program tries to access pages that are not currently mapped to physical memory (RAM) ... This situation is known as a page fault ... The operating system must then take control and handle the page fault, in a manner invisible to the program ...
Memory Protection - Methods - Paged Virtual Memory
... In paging, the memory address space is divided into equal, small pieces, called pages ... Using a virtual memory mechanism, each page can be made to reside in any location of the physical memory, or be flagged as being protected ... Most computer architectures based on pages, most notably x86 architecture, also use pages for memory protection ...
Operating System - Components - Kernel - Virtual Memory
... Main article Virtual memory Further information Page fault The use of virtual memory addressing (such as paging or segmentation) means that the kernel can choose what memory each ... UNIX this kind of interrupt is referred to as a page fault ... When the kernel detects a page fault it will generally adjust the virtual memory range of the program which triggered it, granting it access to the memory requested ...
SIGBUS - Segmentation, Page Fault, and Access Violation - Common Causes
... The following are some typical causes of a segmentation fault Attempting to execute a program that does not compile correctly ... A buffer overflow Using uninitialized pointers Generally, segmentation faults occur because a pointer is NULL, or because it points to random memory (probably never initialized to ... any of these variables could cause a segmentation fault ...

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