Question

Consider the following page reference string: A, B, C, D, B, A, E, F, B, A, B, C, G, F, C, B, A, B, C, F Assuming demand paging with seven frames, how many page faults would oxcur when using Optimal (MIN) replacement algorithm?

Answer 1

Using the Optimal Page Replacement algorithm with seven frames on the given reference string results in a total of 11 page faults.

Step-by-step explanation:

The subject of the question is the Optimal Page Replacement algorithm, which is part of Operating Systems, a sub-discipline of Computers and Technology. The question is asked at the College level, dealing with demand paging in memory management.

The page reference string given is: A, B, C, D, B, A, E, F, B, A, B, C, G, F, C, B, A, B, C, F. Assuming there are seven frames available and using the Optimal Page Replacement algorithm, we want to calculate the number of page faults. The Optimal algorithm replaces the page that will not be used for the longest period of time in the future.

Following the Optimal Page Replacement steps through the reference string, the page faults occur as follows:

1. Load A - Fault
2. Load B - Fault
3. Load C - Fault
4. Load D - Fault
5. Load E - Fault
6. Load F - Fault
7. Replace A with G (A is not needed until farthest) - Fault
8. Replace B with A (B is needed after C) - Fault
9. Replace D with B - Fault
10. Replace E with C - Fault
11. Replace G with F - Fault

Therefore, applying the Optimal algorithm to this reference string with seven frames results in 11 page faults.