Question

A process refers to 5 pages, A, B, C, D, E in the order : A, B, C, D, A, B, E, A, B, C, D, E. If the page replacement algorithm is FIFO, the number of page transfers with an empty internal store of 3 frames is :

a) 8
b) 10
c) 9
d) 7

Answer 1

The number of page transfers with a FIFO page replacement algorithm and an empty internal store of 3 frames is 8.

Step-by-step explanation:

The number of page transfers with a FIFO page replacement algorithm can be determined by tracing the sequence of page requests and keeping track of the pages in the internal store. In this case, the empty internal store has 3 frames. The given page sequence is A, B, C, D, A, B, E, A, B, C, D, E.

Initially, the internal store is empty. As each page is requested, it is checked if it is already in the internal store. If it is not, the oldest page in the internal store is replaced with the requested page.

Tracing through the sequence, the number of page transfers is:

1. Page transfer: A - Internal store: A
2. Page transfer: B - Internal store: A, B
3. Page transfer: C - Internal store: A, B, C
4. Page transfer: D - Internal store: B, C, D
5. Page transfer: A - Internal store: C, D, A
6. No page transfer: B - Internal store: C, D, A
7. Page transfer: E - Internal store: D, A, E
8. Page transfer: A - Internal store: A, E, A
9. No page transfer: B - Internal store: A, E, A
10. Page transfer: C - Internal store: E, A, C
11. Page transfer: D - Internal store: A, C, D
12. Page transfer: E - Internal store: C, D, E

Therefore, the total number of page transfers is 8.