Consider a system with four page frames and a program that uses eight pages. Con

Question

Consider a system with four page frames and a program that uses eight pages. Consider the reference string 0473230177 and assume that all four page frames are initially empty. How many page faults occur assuming: a. FIFO page replacement. b. LRU page replacement. c. Optimal page replacement. In all cases show a diagram (ASCII art recommended) that shows which pages are in which frames throughout time. For instance: would mean that at step 6 page 5 is in frame 0, page 3 is in frame 1, page 2 is in frame 2, page 1 is in frame 3. At step 1 page 0 is in frame 0, and all other three frames are empty. The goal is to fill this table to see what in memory when and thus infer the number of page faults.

Explanation / Answer

a. First-In-First-Out (FIFO) Replacement ---->

So total 8 page faults occur out of 10 page request in FIFO.

b. Least Recently Used (LRU) Replacement----->

So total 8 page faults will occur in LRU.

c. Optimal Replacement ---->

So total 6 page faults will occur in optimal page replacement out of 10 page request.

0 4 7 3 2 3 0 1 7 7 page frame 0 0 0 0 0 2 2 2 2 2 2 page frame 1 4 4 4 4 4 0 0 0 0 page frame 2 7 7 7 7 7 1 1 1 page frame 3 3 3 3 3 3 7 7 page faults * * * * * * * *

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