Operating Systems600.418Virtual Memory

Table of Contents

Operating Systems600.418Virtual Memory

Virtual Memory

Observations

Virtual Memory

Fetch Policy

Demand Paging

Page Fault

Architecture Support

Performance of Demand Paging

Performance Example

Performance Example (cont).

Page Replacement

Page Replacement Algorithms

First In First Out (FIFO)

First In First Out (FIFO)

First In First Out (FIFO)

First In First Out (FIFO)

The Optimal Algorithm (OPT)

The Optimal Algorithm (OPT)

Least Recently Used (LRU)

LRU Implementations

Stack Algorithms

LRU Apprx.: Second-Chance Algorithm

Enhanced Second-Chance

Page Buffering Algorithm

Frame Allocation

Global versus Local Frame Allocation

I/O Interlock

Thrashing

Thrashing (cont.)

Thrashing (cont.)

Page Fault Frequency Scheme

Page Size Considerations

Program Structure

Program Structure

Email: yairamir@cs.jhu.edu

Home Page: http://www.cs.jhu.edu/~yairamir/cs418/600-418.html

Other information:
Operating Systems (600.418), Lecture 6: Virtual Memory