Demand paging

In computer operating systems, demand paging is a simple method of implementing virtual memory. In a system that uses demand paging, the operating system copies a page into physical memory only if an attempt is made to access it (i.e., if a page fault occurs). It follows that a process begins execution with none of its pages in physical memory, and many page faults will occur until most of a process's working set of pages is located in physical memory.

For this reason, prepaging , a method of remembering which pages a process used when it last executed and preloading them, is used to improve performance.

See also

• CPU design
• computer
• memory management
• virtual memory

References

• Tanenbaum, Andrew S. Operating Systems: Design and Implementation (Second Edition). New Jersey: Prentice-Hall 1997.