Lecture 7: Memory Management

Lecture7:MemoryManagement

CSE120:PrinciplesofOpera>ngSystems

UCSanDiego:SummerSessionI,2009 FrankUyeda

Announcements

? PeerWiseques>onsduetomorrow. ? Project2isdueonFriday.

? MilestoneonTuesdaynight.

? Homework3isduenextMonday.

2

GoalsforToday

? Mo>va>onforMemoryManagement ? UnderstandPaging

? Howtotranslatefromvirtualtophysicaladdress ? Determinesize,structureofpagetables

3

MemoryManagement

? Goalsofmemorymanagement

? Provideaconvenientabstrac>onforprogramming ? Allocatescarcememoryresourcesamongcompe>ng

processes ? Maximizeperformancewithminimaloverhead

? Mechanisms

? Physicalandvirtualaddressing ? Techniques:Par>>oning,paging,segmenta>on ? Pagetablemanagement,TLBs,VMtricks

? Policies

? Pagereplacementalgorithms

4

Inthebeginning.....

? Batchprogrammedsystems

? Programsusephysical

SP

addressesdirectly ? OSloadsjob,runsit,unloadsit ? Similartowhatnachosdoes

rightnow

(you'llchangethisinProject2)

PC

PhysicalMemory

Stack

Heap DataSegment TextSegment

Opera>ngSystem

5

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