1) Describe the thrashing phenomenon and how the locality model can be used to overcome thrashing.

2) Assume a physical memory of 4 page frames and initially all frames are empty. Given the reference string 4, 5, 1, 0, 1, 5, 2, 4, 2, 5, 0, 1, 2, 1, 4, show the page replacement procedures and give the number of page faults for the following page replacement policies:

1. OPT
2. LRU
3. Second Chance