The LRU Replacement Algorithm
	ä Associates with each page the time when it was last used ä Replace the page that has not been used for the longest time ä Realizable, but not cheap ä Simulating the LRU Algorithm: Aging ä associate a byte with each page in memory ä periodically, shift all the bits to the right and inserts the reference bit into the high-order bit ä the page with the lowest number is the least recently used page