Types of Page Replacement Methods
Some important Page replacement methods are:-
FIFO Page Replacement
FIFO (First-in-first-out) is a simple implementation method. In this method, memory selects the page for a replacement that has been in the virtual address of the memory for the longest time.
- Whenever a new page loaded, the page recently comes in the memory is removed. So, it is easy to decide which page requires to be removed as its identification number is always at the FIFO stack.
- The oldest page in the main memory is one that should be selected for replacement first.
The optimal page replacement method selects that page for a replacement for which the time to the next reference is the longest.
- Optimal algorithm results in the fewest number of page faults. This algorithm is difficult to implement.
- An optimal page-replacement algorithm method has the lowest page-fault rate of all algorithms. This algorithm exists and which should be called MIN or OPT.
- Replace the page which unlike to use for a longer period of time. It only uses the time when a page needs to be used.
LRU Page Replacement
The full form of LRU is the Least Recently Used page. This method helps OS to find page usage over a short period of time. This algorithm should be implemented by associating a counter with an even- page.
- Page, which has not been used for the longest time in the main memory, is the one that will be selected for replacement.
- Easy to implement, keep a list, replace pages by looking back into time.