Operating system 38 page replacement

Page replacement algorithms are used to select victim frames when free frames are not available to map newly requested pages. This is needed because physical memory is limited and processes continually request new pages, eventually using up all available frames. Page replacement algorithms aim to select pages that are not actively being used to evict from memory, in order to reduce the number of future page faults. Common algorithms include first-in, first-out (FIFO) and least recently used (LRU), which try to replace pages that have not been used for the longest time.