Consider the reference string: 0 1 2 3 0 1 4 0 1 2 3 4 If FIFO page replacement algorithm is used, then the number of page faults with three page frames and…
Consider the reference string: 0 1 2 3 0 1 4 0 1 2 3 4 If FIFO page replacement algorithm is used, then the number of page faults with three page frames and four page frames are _______ and _______ respectively.
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Correct answer: (D) 9, 10
Explanation
Given reference string: 0, 1, 2, 3, 0, 1, 4, 0, 1, 2, 3, 4. (i) FIFO with 3 page frames: faults occur at 0, 1, 2, 3, 0, 1, 4, 2, 3 (hits at the 2nd 0 and 1 after 4). Total page faults = 9. (ii) FIFO with 4 page frames: faults occur at 0, 1, 2, 3, 4, 0, 1, 2, 3, 4 (hits at 0 and 1 before 4 is loaded). Total page faults = 10. This is Belady's anomaly.