1 Project: Page Replacement Algorithms Lubomir Bic

2 Project Description Objective: compare performance of different page replacement algorithms A page replacement algorithm: –At page fault, determines which currently resident page must be evicted and replaced by a new page –Main goal: minimize number of page faults over a period of time Global page replacement: –All resident pages are considered, regardless of who caused the page fault

Project Description To compare performance of different algorithms, we use reference string, RS: r 1 r 2 … r T –each r i is an integer –it represents the page accessed at time i Operating Systems 3

Project Description Assignment: implement and compare –FIFO, LRU, Second Chance Algorithm You will be given a RS in the form of a file Your program must determine (for each algorithm): –number of page faults –the times of their occurrence Output format: N t 1 t 2 … t N –N: total number of page faults for the given RS –each t i represents the time of a page fault Operating Systems 4

Protocol for Testing  See lab assistant due date  Bring your own laptop (or use a lab computer)  Your program must be able to –read text files (.txt extension) from a USB memory –write text files to the same memory stick Operating Systems 5

Protocol for Testing  During test: –create a PM consisting of 16 page frames –initialize PM such that frame i contains the page i –for each algorithm: read RS from file input.txt on memory stick output results into a file nnn.txt, where nnn is your matriculation number, to the same memory stick –output file should contain 3 separate lines of the form N t 1 t 2 … t N – Operating Systems 6

Example Input file: … Output file: … 1 4 … … Operating Systems 7