Consider a main memory with five page frames and the following sequence of…
2015
Consider a main memory with five page frames and the following sequence of page references: 3, 8, 2, 3, 9, 1, 6, 3, 8, 9, 3, 6, 2, 1, 3. Which one of the following is true with respect to page replacement policies First In First Out (FIFO) and Least Recently Used (LRU)?
Answer: A. Both incur the same number of page faults — Answer: Both FIFO and LRU incur 9 page faults for the given reference string with five frames. FIFO — 9 page faults. The first five unique references (3, 8,…
- A.
Both incur the same number of page faults
- B.
FIFO incurs 2 more page faults than LRU
- C.
LRU incurs 2 more page faults than FIFO
- D.
FIFO incurs 1 more page faults than LRU
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Correct answer: A
Answer: Both FIFO and LRU incur 9 page faults for the given reference string with five frames.
FIFO — 9 page faults. The first five unique references (3, 8, 2, 9, 1) fill the frames (5 faults). Subsequent faults occur when 6, 3, 8 and 2 are referenced and are not in frames, adding 4 more faults, for a total of 9.
LRU — 9 page faults. Similarly, the first five unique references cause 5 faults to fill frames. Later references that are not present cause 4 additional faults (6, 8, 2, 1 in the simulation), giving a total of 9.
Conclusion: Since both policies produce the same total number of page faults (9), the statement "Both incur the same number of page faults" is correct; the other numeric difference claims are incorrect.
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