Page replacement and thrashing
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Discussed different page replacement algorithms and their hardware implementation. Explained the cause of thrashing.
Page replacement and thrashing
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- 4. 3/3/2021 4 7 7 0 7 0 1 2 0 1 2 3 1 2 3 0 4 3 0 4 2 0 4 2 3 0 2 3 0 1 3 0 1 2 7 1 2 7 0 2 7 0 1 7 0 1 2 3 0 4 2 3 0 3 2 1 2 0 1 7 0 1 0 Number of page fault = 15
- 5. 3/3/2021 5 7 7 0 7 0 1 7 0 1 2 3 0 1 2 3 4 1 2 3 4 0 2 3 4 0 1 2 4 0 1 2 7 0 1 7 0 1 2 3 0 4 2 3 0 3 2 1 2 0 1 7 0 1 0 Number of page fault = 10 Page fault decreases with the increase of frame size
- 6. 3/3/2021 6 For some page-replacement algorithms e.g., FIFO, page fault increases with the increase in frame size This weird scenario is known as Belady’s anomaly
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- 9. 3/3/2021 9 7 7 0 7 0 1 2 0 1 2 0 3 2 4 3 2 0 3 2 0 1 7 0 1 7 0 1 2 3 0 4 2 3 0 3 2 1 2 0 1 7 0 1 0 Number of page fault = 9
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- 11. 3/3/2021 11 7 7 0 7 0 1 2 0 1 2 0 3 4 0 3 0 3 2 1 3 2 7 0 1 7 0 1 2 3 0 4 2 3 0 3 2 1 2 0 1 7 0 1 0 Number of page fault = 12 4 0 2 4 3 2 1 0 2
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- 14. 3/3/2021 14 7 0 7 1 0 7 2 1 0 7 0 3 2 1 7 7 0 1 2 0 7 3 3 2 1 0 7 7 0 3 2 1
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