# Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 33 (Page No. 257)

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Suppose that the $\text{WSClock}$ page replacement algorithm uses a $\tau$ of two ticks, and the system state is the following:

where the three flag bits $V, R,$ and $M$ stand for Valid, Referenced, and Modified, respectively.

1. If a clock interrupt occurs at tick $10,$ show the contents of the new table entries. Explain. (You can omit entries that are unchanged.)
2. Suppose that instead of a clock interrupt, a page fault occurs at tick $10$ due to a read request to page $4.$ Show the contents of the new table entries. Explain. (You can omit entries that are unchanged.)

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