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How many page faults occur in LRU page replacement algorithm for the given reference string, with four-page frames 7, 0, 1, 2, 0, 3, 4, 2, 3, 0, 3, 2, 1, 2, 0, 1

How many page faults occur in LRU page replacement algorithm for the given reference string, with four-page frames 7, 0, 1, 2, 0, 3, 4, 2, 3, 0, 3, 2, 1, 2, 0, 1 Correct Answer 7

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  • Assuming demand paging concept and initially all 4 frames are empty so 7,0,1,2 all are page faults
  • Page number 0 is already present, no page fault
  •  Page number 3 will replace by page number 7 so 3 is a page fault
  • Page number 1 will replace by page number 4 not by page number 0 because 0 page number is used recently and we have to replace by least recently used.
  • Page number 2, 3, 0, 3, 2 are already present, no page fault  
  • Page number 4 will replace by 1 page number, page fault


So total 7 page faults occurred

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