CMSC412 Solution

Demand paging problems (page replacement algorithms):

1. For the following reference string apply the FIFO page replacement algorithm.

– Option 1 – according to Week 6 – Textbook Readings:
Reference string 2 4 5 6 1 5 3 4 5 2 3 6 5 3 4 7 3 5 6
Physical frame 0 2 2 2 2
Physical frame 1 4 4 4
Physical frame 2 5 5
Physical frame 3 6
Page faults F F F F
Victim frames
OR
– Option 2 – according to Week 6 - Module Readings
Reference string 2 4 5 6 1 5 3 4 5 2 3 6 5 3 4 7 3 5 6
Physical frame 0 2 4 5 6
Physical frame 1 2 4 5
Physical frame 2 2 4
Physical frame 3 2
Page faults F F F F
Victim frames

2. For the following reference string apply the OPT page replacement algorithm.
Reference string 2 4 5 6 1 5 3 4 5 2 3 6 5 3 4 7 3 5 6
Physical frame 0 2 2 2 2
Physical frame 1 4 4 4
Physical frame 2 5 5
Physical frame 3 6
Page faults F F F F
Victim frames

3. For the following reference string apply the LRU page replacement algorithm.
Reference string 2 4 5 6 1 5 3 4 5 2 3 6 5 3 4 7 3 5 6
Physical frame 0 2 2 2 2
Physical frame 1 4 4 4
Physical frame 2 5 5
Physical frame 3 6
Page faults F F F F
Victim frames

4. For the following reference string apply the LFU page replacement algorithm.
Reference string 2 4 5 6 1 5 3 4 5 2 3 6 5 3 4 7 3 5 6
Physical frame 0 2 2 2 2
Physical frame 1 4 4 4
Physical frame 2 5 5
Physical frame 3 6
Page faults F F F F
Victim frames