Demand paging and pager in operating systems

Demand paging and pager in operating systems

In this tutorial, we will try to cover the Demand paging and pager in operating systems.

What are pages?

To load many processes on the main memory at the same time, operating systems(OS) creates different pages for a process.

For example, if we have a process P1, then OS can create the pages like

Page 1, Page 2, Page 3 etc.

Now, it means that if we want to load Process P1 on the main memory, the OS only loads the required pages of the process P1.

What is demand paging?

Demand paging is a memory management technique in which OS only loads the required pages in main memory.

A pager is used to swap in and swap out the pages. Here keep in mind that pager swap in and swap out pages, but in swapper, swaps in, and swaps out the complete processes.  Read More 

demand paging in operating systems
Figure: Demand paging in operating systems

Topic Covered

Demand paging and pager in operating systems.