Thread: Page faults

  1. #1
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    Jun 2011

    Page faults

    Consider the two dimensional array A:
    int A[ ] [ ] = new int [50] [50]
    where A[0] [0] is at location 400, in a paged system with pages of size 400. A small process is in page 0 (locations 0 to 399) for manipulating the matrix; thus, every instruction fetch will be from page 0.
    For three page frames, how many page faults are generated by the following array-initialization loops, using LRU replacement, and assuming page frame 1 has the process in it, and the other two are initially empty:
    for (int j = 0; j < 100; j++)
    for (int i = 0; i < 100; i++)
    A[i][j] = 0;
    My answer:I workout 625 faults for above.Anyone correct me if i am wrong.
    Last edited by jackhuman; 06-25-2011 at 01:45 PM.

  2. #2
    and the hat of int overfl Salem's Avatar
    Join Date
    Aug 2001
    The edge of the known universe
    > int A[ ] [ ] = new int [50] [50]
    > for (int j = 0; j < 100; j++)
    So what about segmentation faults when you access memory outside of your array bounds?

    Are you assuming anything about the size of an integer?
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.

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