Lecture 7: Memory Management

Lecture 7: Memory Management

CSE 120: Principles of Opera>ng Systems

UC San Diego: Summer Session I, 2009

Frank Uyeda

Announcements

? PeerWise ques>ons due tomorrow.

? Project 2 is due on Friday.

¨C Milestone on Tuesday night.

? Homework 3 is due next Monday.

2

Goals for Today

? Mo>va>on for Memory Management

? Understand Paging

¨C How to translate from virtual to physical address

¨C Determine size, structure of page tables

3

Memory Management

? Goals of memory management

¨C Provide a convenient abstrac>on for programming

¨C Allocate scarce memory resources among compe>ng

processes

¨C Maximize performance with minimal overhead

? Mechanisms

¨C Physical and virtual addressing

¨C Techniques: Par>>oning, paging, segmenta>on

¨C Page table management, TLBs, VM tricks

? Policies

¨C Page replacement algorithms

4

In the beginning¡­..

Physical Memory

? Batch programmed systems

¨C Programs use physical

addresses directly

¨C OS loads job, runs it, unloads it

¨C Similar to what nachos does

right now

Stack

SP

Heap

Data Segment

(you¡¯ll change this in Project 2)

PC

Text Segment

Opera>ng System

5

 ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download