The problem with Paging

Paging causes the internal fragmentation which occurs because not every memory region is an exact multiple of the page size. Imagine a program of size 101, it would still need three pages of size 50, so it would occupy 49 bytes more than needed. There are 3 algorithms of paging

First In First Out (FIFO)

This is the simplest page replacement algorithm. In this algorithm, the operating system keeps track of all pages in the memory in a queue, the oldest page is in the front of the queue. When a page needs to be replaced, the page in the front of the queue is selected for removal.

Least Recently Used (LRU) :

In this algorithm, the pages which will be replaced are those which are the least recently used.

Optimal Page replacement :

In this algorithm, the pages which will be replaced are those which will not be used for the longest duration of time in the future.

Index page

Algorithms of paging