Question:

In a page virtual storage system, each process has 4 memory allocation memory block. When the process begins executing, data area is empty. If now it calls the pages in the program with this sequence:

5,3,6,4,3,5,1,4,2,5,6,4,2,5,1

Write down the number of page faults when using FIFO page-replacement algorithm and draw the Page trend graph.

Answer:

There are total 10 page faults.

5  3  6  4  3  5  1  4  2  5  6  4  2  5  1

5  3  6  4  4  4  1  1  2  5  6  4  4  4  1

    5  3  6  6  6  4  4  1  2  5  6  6  6  4

        5  3  3  3  6  6  4  1  2  5  5  5  6

            5  5  5  3  3  6  4  1  2  2  2  5

f   f   f  f            f       f   f   f   f            f