-Consider the following page reference string: (6 pts)

7, 2, 3, 1, 2, 5, 3, 4, 6, 7, 7, 1, 0, 5, 4, 6, 2, 3, 0 ,1.

Assuming demand paging with three frames, how many page faults would occur for the following replacement algorithms?

LRU replacement

FIFO replacement

Optimal replacement

-What is the cause of thrashing? How does the system detect thrashing? Once it detects thrashing, what can the system do to eliminate this problem? (5 pts)

-Consider a demand-paging system with the following time-measured utilizations:

(10 pts)

CPU utilization 20%

Paging disk 97.7%

Other I/O devices 5%

For each of the following, indicate whether it will (or is likely to) improve

CPU utilization. Explain your answers.

Install a faster CPU.

Install a bigger paging disk.

Increase the degree of multiprogramming.

Decrease the degree of multiprogramming.

Install more main memory.