Virtual Memory and Demand Paging
page 4 of 8
by Joydip Kanjilal
Feedback
Average Rating: 
Views (Total / Last 10 Days): 98008/ 47

Demand Paging

In Virtual Memory Systems the pages are not loaded in the memory until they are "demanded" by a process; hence the name, Demand Paging.  Demand paging allows the various parts of a process to be brought into physical memory as the process needs them to execute.

In virtual memory systems, demand paging is a type of swapping in which pages of data are not copied from disk to RAM until they are needed.  In contrast, some virtual memory systems use anticipatory paging in which the operating system attempts to anticipate which data will be needed next and copies it to RAM before it is actually required.  For a process to execute, all the structures for data, text, and so on have to be set up.  Pages are not loaded in memory until they are "demanded" by a process.  Thus we get the term "demand paging."  Demand paging allows the various parts of a process to be brought into physical memory as the process needs them to execute.


View Entire Article

User Comments

Title: virtual memory and paging concepts   
Name: Suganthi Velusamy
Date: 2006-12-28 1:10:43 AM
Comment:
This is very very useful for me to know about the virtual memory concets and paging concepts clearly. Thanks a lot for you to make me to get a clear idea of what is virtul memory and all of its corresponding operations. Can u please guide me by an article for threading concepts in detailed manner?
Title: Mapping virtual address to physical   
Name: Swetha
Date: 2006-10-15 3:07:27 PM
Comment:
Hello Sir,

The article is very good for beginners like me.But ca you tell me whether can I write a code to map virtual address to physical addres.

Warm Regards
swetha
Title: Suggestion   
Name: Sandeep Acharya
Date: 2006-08-30 12:30:59 PM
Comment:
The article is really good. We all know that covering the paging concept in a small article is very tough. But I guess it could be better if you can throw some more light on the "Pure demand Paging" and how it could "Thrash" an application. I guess a pictorial/graphical explanation could be better. ANyway its a suggestion only. And I am really appriciating the article. Hoping to have some good articles like this in future.

Product Spotlight
Product Spotlight 





Community Advice: ASP | SQL | XML | Regular Expressions | Windows


©Copyright 1998-2024 ASPAlliance.com  |  Page Processed at 2024-07-23 1:43:42 PM  AspAlliance Recent Articles RSS Feed
About ASPAlliance | Newsgroups | Advertise | Authors | Email Lists | Feedback | Link To Us | Privacy | Search