Segmentation


### more classical method before paging but used in virtual address image
**가변적인 영역인 세그먼트(segment)로**
**내부 단편화 X, 외부 단편화 O**


- like paging - it has segment table also in each process
Logical address consists of a two tuple - <segment-number, offset>
Segment-table base register (STBR), Segment-table length register (STLR) exist
- **has segment number s(identify segment) and d index(of process entry)- Maps two-dimensional physical addresses**each entry has base and limit
![](https://www.notion.so/image/https%3A%2F%2Fs3-us-west-2.amazonaws.com%2Fsecure.notion-static.com%2Fa58476a4-a0c8-4077-aa61-4aa199746880%2FUntitled.png?table=block&id=2c19b285-1a31-4664-8470-b281f9517a36&cache=v2)
Has also relocation, sharing, allocation issue for fragmentation
![](https://www.notion.so/image/https%3A%2F%2Fs3-us-west-2.amazonaws.com%2Fsecure.notion-static.com%2F74859a9e-2904-49ab-80d3-450c8e24a75c%2FUntitled.png?table=block&id=4927863d-e58e-41d0-9615-2fa88e16f7fa&cache=v2)

> [세그먼테이션(segmentation) VS 페이징(paging)](https://blog.naver.com/PostView.nhn?blogId=qbxlvnf11&logNo=221368476938&parentCategoryNo=&categoryNo=&viewDate=&isShowPopularPosts=false&from=postView)




