Page Replacement Algorithms
Optimal Algorithm
Definition – replace the page that will not be used for longest period of time
Requires future knowledge of process page needs
Advantages – improved performance
Drawbacks – difficult to implement
Definition – replace the page that has not been used for the longest period of time; it is an approximation to the optimal algorithm
Advantages – better performance than FIFO; doesn’t suffer from Belady’s anomaly
Drawbacks – suffers from replacing a page that is just about to be used; may require substantial hardware assistance