1. This algorithm is a result of discovery by Belady’s Anomaly. 2. This technique replace the page that won’t be in use for longest time. 3. When a page replacement is needed, it looks ahead in the input queue for the page frame which will be referenced only after a long time. 4. The page with the longest reference is swapped. 5. Optimal Page Replacement technique reduces the page faults to the minimum.
Advantages: It has the lowest page fault rate. It never suffers from Belady’s Anomaly.
Disadvantages: This technique is difficult to implement because it needs future knowledge.