GATE Overflow | Operating Systems | Test 1 | Question: 16

Question

Determine the number of page faults when references to pages occur in the sequence -$1,2,4,5,2,1,2,4$. Assume that the main memory can accommodate 3 pages and  already has pages 1, 2 with page 1 having been brought earlier than page 2 and LRU being the replacement strategy used.

Answer 1

We have to consider only the page faults occuring after 1,2 as it is the given initial condition 

Comments

I did wrong just because of sequence - 1,2,4......  I took the value -1 instead of 1

Answer 2

Answer is - 4

Comments

I think this is numerical based question, because their was no blank space or options to be marked in the paper.

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how 4? plz explain

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Please remove minus sign from the sequence. I misunderstood it and took 1 as -1.