GATE Overflow Test Series | Operating Systems | Test 2 | Question: 7

Question

Which of the following page replacement algorithms exhibit Belady's anomaly? (Mark all the appropriate choices)

• A. Optimal page replacement
• B. First in First out (FIFO)
• C. Least recently used (LRU)
• D. Random page replacement

Answer 1

A page replacement algorithm suffers from Belady's anomaly when it is not a stack algorithm.

• FIFO suffers Belady's anomaly, but not always.
• Random page replacement, it may choose a page to replace in a FIFO manner or in a manner that does not satisfy the stack algorithm. This means it could suffer from Belady's anomaly.

So, the correct answer is $B;D.$