Virtual Memory Computer Science Engineering (CSE) Notes | EduRev

Computer Science Engineering (CSE) : Virtual Memory Computer Science Engineering (CSE) Notes | EduRev

 Page 1


2014/10/20 \course\cpeg323-08F\Topic7e 1 
Virtual Memory 
Page 2


2014/10/20 \course\cpeg323-08F\Topic7e 1 
Virtual Memory 
2014/10/20 \course\cpeg323-08F\Topic7e 2 
Historically, there were two major motivations for virtual 
memory: to allow efficient and safe sharing of memory 
among multiple programs, and to remove the 
programming burden of a small, limited amount of main 
memory. 
     Patt&Henn 04 
 
…a system has been devised to make the core drum 
combination appear to programmer as a single level 
store, the requisite transfers taking place automatically 
     Kilbum et al. 
Virtual Memory:  Motivation 
Page 3


2014/10/20 \course\cpeg323-08F\Topic7e 1 
Virtual Memory 
2014/10/20 \course\cpeg323-08F\Topic7e 2 
Historically, there were two major motivations for virtual 
memory: to allow efficient and safe sharing of memory 
among multiple programs, and to remove the 
programming burden of a small, limited amount of main 
memory. 
     Patt&Henn 04 
 
…a system has been devised to make the core drum 
combination appear to programmer as a single level 
store, the requisite transfers taking place automatically 
     Kilbum et al. 
Virtual Memory:  Motivation 
2014/10/20 \course\cpeg323-08F\Topic7e 3 
• Provide sharing 
• Automatically manage the M hierarchy (as “one-level”) 
• Simplify loading (for relocation) 
MAIN 
PROCESSOR 
MEMORY 
MANAGE- 
MENT 
UNIT 
HIGH- 
SPEED 
CACHE 
MAIN 
MEMORY 
BACKING 
STORE 
LOGICAL 
ADDRESS 
CONTROL 
DATA 
PHYSICAL ADDRESS 
Purpose of Virtual Memory 
Page 4


2014/10/20 \course\cpeg323-08F\Topic7e 1 
Virtual Memory 
2014/10/20 \course\cpeg323-08F\Topic7e 2 
Historically, there were two major motivations for virtual 
memory: to allow efficient and safe sharing of memory 
among multiple programs, and to remove the 
programming burden of a small, limited amount of main 
memory. 
     Patt&Henn 04 
 
…a system has been devised to make the core drum 
combination appear to programmer as a single level 
store, the requisite transfers taking place automatically 
     Kilbum et al. 
Virtual Memory:  Motivation 
2014/10/20 \course\cpeg323-08F\Topic7e 3 
• Provide sharing 
• Automatically manage the M hierarchy (as “one-level”) 
• Simplify loading (for relocation) 
MAIN 
PROCESSOR 
MEMORY 
MANAGE- 
MENT 
UNIT 
HIGH- 
SPEED 
CACHE 
MAIN 
MEMORY 
BACKING 
STORE 
LOGICAL 
ADDRESS 
CONTROL 
DATA 
PHYSICAL ADDRESS 
Purpose of Virtual Memory 
2014/10/20 \course\cpeg323-08F\Topic7e 4 
Structure of Virtual Memory 
Virtual Address 
Address Translator 
Physical Address 
From Processor 
To Memory 
Page fault 
 
Using elaborate 
Software  
page fault 
Handling 
algorithm 
 
Page 5


2014/10/20 \course\cpeg323-08F\Topic7e 1 
Virtual Memory 
2014/10/20 \course\cpeg323-08F\Topic7e 2 
Historically, there were two major motivations for virtual 
memory: to allow efficient and safe sharing of memory 
among multiple programs, and to remove the 
programming burden of a small, limited amount of main 
memory. 
     Patt&Henn 04 
 
…a system has been devised to make the core drum 
combination appear to programmer as a single level 
store, the requisite transfers taking place automatically 
     Kilbum et al. 
Virtual Memory:  Motivation 
2014/10/20 \course\cpeg323-08F\Topic7e 3 
• Provide sharing 
• Automatically manage the M hierarchy (as “one-level”) 
• Simplify loading (for relocation) 
MAIN 
PROCESSOR 
MEMORY 
MANAGE- 
MENT 
UNIT 
HIGH- 
SPEED 
CACHE 
MAIN 
MEMORY 
BACKING 
STORE 
LOGICAL 
ADDRESS 
CONTROL 
DATA 
PHYSICAL ADDRESS 
Purpose of Virtual Memory 
2014/10/20 \course\cpeg323-08F\Topic7e 4 
Structure of Virtual Memory 
Virtual Address 
Address Translator 
Physical Address 
From Processor 
To Memory 
Page fault 
 
Using elaborate 
Software  
page fault 
Handling 
algorithm 
 
2014/10/20 \course\cpeg323-08F\Topic7e 5 
Page 0
Page 1
Page 2
Page 3
Page 4
Page 5
Page 6
Page 7
Page 8
Page 9
Page 10
Page 11
Page 12
Page 13
Page 14
Page 15
0
4096
8192
12288
16384
20480
24576
28672
Page Frame 0
Page Frame 1
Page Frame 2
Page Frame 3
Page Frame 4
Page Frame 5
Page Frame 6
Page Frame 7
} 4K } 4K 
Virtual 
address 
Main 
memory 
address 
0
4096
8192
12288
16384
20480
24576
28672
32768
36864
40960
45056
49152
53248
57344
61440
64K virtual address space      32K main memory 
A Paging System 
Read More
Offer running on EduRev: Apply code STAYHOME200 to get INR 200 off on our premium plan EduRev Infinity!

Related Searches

MCQs

,

Important questions

,

Viva Questions

,

Extra Questions

,

Previous Year Questions with Solutions

,

study material

,

Free

,

ppt

,

shortcuts and tricks

,

Virtual Memory Computer Science Engineering (CSE) Notes | EduRev

,

Objective type Questions

,

past year papers

,

Exam

,

Virtual Memory Computer Science Engineering (CSE) Notes | EduRev

,

Semester Notes

,

Virtual Memory Computer Science Engineering (CSE) Notes | EduRev

,

practice quizzes

,

video lectures

,

Sample Paper

,

pdf

,

Summary

,

mock tests for examination

;