Question

The implementation of the LFU and the MFU algorithm is very uncommon because :

a) they are too complicated
b) they are optimal
c) they are expensive
d) All of the mentioned

Answer 1

LFU and MFU algorithms are uncommon due to the expense of their computational overhead, which involves tracking the frequency of item accesses and can be costly for large caches.

Step-by-step explanation:

The LFU (Least Frequently Used) and the MFU (Most Frequently Used) algorithms are caching algorithms that are not commonly implemented. The rarity of their implementation can be attributed to their expense in terms of computational overhead.

Unlike simpler algorithms like LRU (Least Recently Used), LFU and MFU require tracking the frequency of accesses to each item in the cache, which can become costly with a large number of items. Moreover, in some scenarios, these algorithms may not offer a significant performance improvement over simpler or more commonly used algorithms. Therefore, the correct answer to why the implementation of LFU and MFU is uncommon is that they are expensive.

Answer 2

The implementation of the LFU and the MFU algorithm is very uncommon because they are expensive (Option C).

Step-by-step explanation:

The implementation of the Least Frequently Used (LFU) and the Most Frequently Used (MFU) algorithms is very uncommon because they are considered expensive in terms of computational resources. Both of these caching algorithms require keeping track of the frequency of access for the items stored in the cache, which can be resource-intensive. LFU removes the item that has been accessed least frequently when making room for new content, while MFU removes the one accessed most frequently, under the assumption that an item accessed frequently in the past will not be accessed again in the near future.

The computational overhead for maintaining access counters and constantly sorting items based on these counters can hinder the performance and scalability of systems employing the LFU or MFU page replacement algorithms as compared to simpler methods such as Least Recently Used (LRU).

Thus, the correct choice from the options is c) they are expensive.