Operating System - FIFO (First-In-First-Out) Page Replacement Algorithm

Definition:
FIFO is one of the simplest page replacement algorithms used in virtual memory management. It works on the principle of replacing the oldest page in memory — the one that was loaded first.

How It Works:

• Pages are stored in a queue.

• When a new page needs to be loaded:

  • If there’s space, it's simply added.

  • If memory is full, the oldest page (front of the queue) is removed and the new page is added to the end.

Example

Pros:

• Simple and easy to implement.

Cons:

• Doesn’t consider page usage frequency.

• Can suffer from Belady’s anomaly (more frames can lead to more faults!