random or pseudo+random number generator the overhead involved in implementing this policy is an ( additional amount of work per page replacement moreoverthere is no additional overhead for each page requestother than to determine whether page request is in the cache or not stillthis policy makes no attempt to take advantage of any temporal or spatial localities that user' browsing exhibits the fifo strategy is quite simple to implementas it only requires queue to store references to the pages in the cache pages are enqueued in when they are referenced by browserand then are brought into the cache when page needs to be evictedthe computer simply performs dequeue operation on to determine which page to evict thusthis policy also requires ( additional work per page replacement alsothe fifo policy incurs no additional overhead for page requests moreoverit tries to take some advantage of temporal locality the lru strategy goes step further than the fifo strategyfor the lru strategy explicitly takes advantage of temporal locality as much as possibleby always evicting the page that was least+recently used from policy point of viewthis is an excellent approachbut it is costly from an implementation point of view that isits way of optimizing temporal and spatial locality is fairly costly implementing