Os Memory Management Questions Medium
The Most Recently Used (MRU) page replacement algorithm is a memory management technique used by operating systems to determine which page to replace when a page fault occurs. It is based on the principle that the page that has been most recently used is likely to be used again in the near future.
When a page fault occurs, the operating system checks the page table to determine if the required page is present in the main memory or if it has been swapped out to the secondary storage. If the page is not present in the main memory, a page replacement is required.
In the MRU algorithm, the operating system selects the page that has been most recently used for replacement. This is determined by keeping track of the access time of each page. Whenever a page is accessed, its access time is updated to the current time. When a page fault occurs, the operating system scans through the page table to find the page with the highest access time, indicating that it has been most recently used.
Once the page to be replaced is identified, the operating system swaps it out from the main memory and brings in the required page from the secondary storage. The page table is updated accordingly to reflect the new page mapping.
The MRU algorithm is relatively simple to implement and can be effective in certain scenarios. It tends to work well when there is a high degree of temporal locality, meaning that recently accessed pages are likely to be accessed again in the near future. However, it may not perform optimally in situations where there is a high degree of spatial locality, where pages that are physically close to each other are likely to be accessed together.
Overall, the MRU page replacement algorithm aims to maximize the utilization of the main memory by keeping the most recently used pages in it. By replacing the least recently used pages, it helps to minimize the number of page faults and improve the overall system performance.