Question

Which of the following Page Replacement Algorithm suffers from the belady's anomaly?
1. LRU
2. Optimal Page Replacement 
3. FIFO
4. Both LRU and FIFO

Answer 1

Correct Answer - Option 3 : FIFO

Concepts:

Belady’s anomaly is that the page-fault rate may increase as the number of allocated frames increases.

Explanation:

In FIFO Page Replacement Algorithm, page fault rate may increase as the number of allocated frames increase. Hence its suffer from the belady's anomaly

Example:

For this let us consider an example of FIFO case, if we consider the reference string 3  2 1 0 3 2 4 3 2 1 0 4 and 3 frame slots, in this we get 9 page fault but if we increase slots to 4, then we get 10-page faults