Os Memory Management Questions
The least recently used (LRU) page replacement algorithm is a memory management technique used by operating systems to decide which page to replace when there is a page fault (i.e., when a requested page is not present in the main memory).
The LRU algorithm works on the principle that the page that has not been accessed for the longest time is the least likely to be used in the near future. It maintains a record of the order in which pages are accessed and replaces the page that was least recently used.
To implement the LRU algorithm, the operating system keeps track of the access history of each page using a data structure such as a linked list or a stack. Whenever a page is accessed, it is moved to the front of the list or stack, indicating that it is the most recently used page. When a page fault occurs and there is no free space in the main memory, the operating system replaces the page at the end of the list or stack, which represents the least recently used page.
By using the LRU algorithm, the operating system aims to minimize the number of page faults and improve overall system performance by keeping frequently used pages in the main memory. However, implementing the LRU algorithm can be computationally expensive as it requires updating the access history for every memory access.