Q3. Which is better, optimal page replacement algorithm or FIFO page replacement algorithm?
Ans. Optimal page replacement algorithm is better because this algorithm has the lowest page fault rate of all algorithms and will never suffer from Belady’s Anomaly.
Whereas in FIFO after we replace an active page with a new one, a fault occurs almost immediately to retrieve the active page, some other page will need to be replaced to bring the active page back into memory, so a bad replacement choice increase the page fault rate and slow process execution.
The LRU replacement, the set of pages in memory would be most recently referred pages. If the number of frames is increased these ‘n’ pages will still be the most recently referenced and so will still be in memory.