Virtual Memory Essay

Running Head: UNIT 4 PROJECT – VIRTUAL MEMORY









Unit 4 Project – Virtual Memory

Dan Begley
IT320 Operating Systems Concepts
Abdellah Tazi
February 21, 2009

Table of Contents
Cover Page
Table of Contents
Abstract
Virtual Memory (Part 1)
Virtual Memory (Part 2)
References
















Abstract
Using the link http://courses.cs.vt.edu/~csonline/OS/Lessons/VirtualMemory/index.html , to display the simulation, the student was directed to press the “Start” button in order to initiate a sequence of operation in which the 8 processes that take turns referencing memory locations were accesses.   Using the second simulation the student could actually see the effects on FIFO, LRU, LFU, SC and Random in the parameters of number of page faults, total number of page references and page fault rate %.
















Unit 4 Project – Virtual Memory
Part 1.
After pressing the “Start” button, a sequence of operation was initiated in which the 8 processes took turns referencing the memory locations. The boxes then turned dark blue, which indicated that a process was running. When that box would change to light blue, it indicated that the process was ready to be run, but hadn’t started as it was waiting for its turn.   At first the page frames were white; which indicated that the frame was empty. After the start button was pressed and the simulation progress began, the running process chose a specific page.
If a page fault occurred, then the process would change color to red, and the requested page would be put into primary memory. The "new" pages in the page table were green. If a process wrote to a page, then the page would change from green to yellow. This indicated that the contents of the page had changed as well as the fact that it should be copied back to disk before being replaced by another page, (Coutinho, 1996).
Part 2.
The second simulation figure illustrated the behavior of each of the five page...