Os Memory Management Questions Medium
The LFU-K (Least Frequently Used with K bits) page replacement algorithm is a variation of the LFU (Least Frequently Used) algorithm that takes into account both the frequency and recency of page accesses. It aims to replace the page that has been accessed the least frequently, considering the last K bits of the reference string.
Here is a step-by-step description of how the LFU-K algorithm works:
1. Initialize a counter for each page in memory to keep track of its frequency of access.
2. Whenever a page is referenced, increment its counter by 1.
3. When a page needs to be replaced, select the page with the lowest frequency count. If there are multiple pages with the same lowest frequency count, use the K bits of the reference string to determine the least recently used page.
4. If the K bits of the reference string are all 0s or all 1s, the algorithm behaves like the LFU algorithm, selecting the page with the lowest frequency count.
5. If the K bits of the reference string are a mix of 0s and 1s, the algorithm considers the recency of page accesses. It selects the page with the lowest frequency count among the pages that have been accessed recently.
6. After replacing a page, reset its frequency count to 0 and update the reference string accordingly.
7. Continue this process for subsequent page references.
The LFU-K algorithm aims to strike a balance between considering the frequency and recency of page accesses. By incorporating the K bits of the reference string, it can adapt to different access patterns and make more informed decisions when selecting pages for replacement.