Paging is a memory management scheme that permits the physical address space of a memory process to be non-contiguous. 

It avoids the problem of fitting memory chunks of varying sizes onto the backing store.

Scope

This article explains paging in detail.

Definition

It is an efficient memory management technique. It is a non-contiguous memory allocation technique. 

• It involves breaking physical memory into fixed-sized blocks called frames and breaking logical memory into blocks of the same size called pages. In paging, the main memory or physical memory is divided into the fixed-size block called a frame, and the logical address space of the user process or user job is divided into a fixed-size block called a page.
• The page size or the frame size should be equal.
• The size of the page and frame is decided by the operating system of the computer.
• The Operating system maintains a data structure called a page table. The information contained in the page table helps in mapping and framing.
• The information included in the page table is allocated frames present in the main memory.
• The page table mainly consists of two fields: page no. and frame no. 
• The address generated by the CPU is divided into two parts:
  Page no. which maintains indexes in the page table.
  Page offset/displacement.

Question: Two jobs are present in a ready queue. The size of Job 1 is 16 kb and Job 2 is 28 kb and the size of the main memory is 76kb. How the memory is allocated for required jobs 1 and 16, frame size = 4 

Given:
Job 1 = 16 kb
Job 2 = 28 kb
Main memory = 76 kb
Frame size = 4

Paging supports:

1. Virtual memory management.
2. Time-sharing system.
3. Code reusability by number of processes 
4. Multiprogramming 

The major drawback of paging is caused by the page break.

We can understand page break with an example: Suppose a job size is 17 kb and we assume that size of the page is 4. We need 5 pages for the job and when we load the job into the main memory we need 5 frames. The last frame allocates 1 kb space and for the rest 4 kb is allocated. In this 3 kb is wasted. This is called page break.

Summary

Paging involves breaking physical memory into fixed-sized blocks called frames and breaking logical memory into blocks of the same size called pages. When a process is to be executed, the pages are loaded into any available memory frames from the backing store.

Special thanks to Ami Jangid for contributing to this article on takeUforward. If you also wish to share your knowledge with the takeUforward fam, please check out this article