Segmentation in Operating System

In computer memory management, Segmentation is an important technique that efficiently manages memory by dividing a process into its logical parts. The purpose of segmentation is to ensure that different parts of a process (like code, data, stack, etc.) can be stored in different locations in memory and accessed independently. This technique helps to overcome the limitations found in techniques like contiguous allocation and paging.

Segmentation is a memory management scheme in which a process is divided into different logical segments, where each segment has its own name and length. These segments can be stored anywhere in physical memory, but each segment operates independently. For each segment, a Segment Table is created, which stores the base address and the length of that segment.

Each process can be logically divided into the following segments: Code Segment, Data Segment, Stack Segment, and Heap Segment. Each segment can have a different size and length and can be accessed independently.

1. Pure Segmentation: All segments of a process are logically divided and allocated different physical memory blocks.

2. Segmentation with Paging: A hybrid memory management scheme where both segmentation and paging are used. Each segment is divided into smaller pages. This helps solve the problem of external fragmentation.

A segment table is created for each process, containing the base address and limit for each segment. The CPU uses this table to translate a logical address (Segment Number, Offset) into a physical address (`Physical Address = Base Address + Offset`).