GATE - 2007 | OS | A virtual memory system uses First In First Out (FIFO) page replacement

GATE - 2007 [Operating System]

Question:

A virtual memory system uses First In First Out (FIFO) page replacement policy and allocates a fixed number of frames to a process. Consider the following statements:

P: Increasing the number of page frames allocated to a

   process sometimes increases the page fault rate.

Q: Some programs do not exhibit locality of reference.

Which one of the following is TRUE?

A	Both P and Q are true, and Q is the reason for P
B	Both P and Q are true, but Q is not the reason for P
C	P is false, but Q is true
D	Both P and Q are false

   

Solution:

Option (B) is Correct.

Statement P,

FIFO suffers from Belady anomaly. Belady anomaly states that when number of page frames increases no. of page fault increases.

Statement Q,

Locality of reference also known as the principle of locality, is the tendency of a processor to accesses the same set of memory locations respectively over a short period of time.

And yes some programs do not exhibit locality of reference.

Hence, both P and Q are true. But Q is not the reason for P.

Thank You