Comparing Page Replacement Algorithms: Optimal, LRU, and FIFO

Compare the performance of Optimal, LRU (Least Recently Used), and FIFO (First-In, First-Out) page replacement algorithms using a numerical example. This problem demonstrates how each algorithm handles page replacements and highlights their differences in minimizing page faults.

Comparing Page Replacement Algorithms: A Numerical Example

Problem Statement

This example compares three common page replacement algorithms—Optimal, Least Recently Used (LRU), and First-In, First-Out (FIFO)—to illustrate their differences in terms of page faults. We'll use the reference string 4, 7, 6, 1, 7, 6, 1, 2, 7, 2 and 3 available frames.

Optimal Page Replacement Algorithm

The optimal page replacement algorithm replaces the page that will not be used for the longest time in the future. This is an ideal algorithm, but it is not practical because it requires future knowledge of the reference string.

Number of page faults: 5

LRU Page Replacement Algorithm

The Least Recently Used (LRU) algorithm replaces the page that hasn't been used for the longest time. It's a practical algorithm that doesn't require future knowledge.

Number of page faults: 6

FIFO Page Replacement Algorithm

The First-In, First-Out (FIFO) algorithm replaces the page that has been in memory the longest. It's simple to implement but can be less efficient than other algorithms.

Number of page faults: 6