Assume that a virtual memory is managed using a buffer pool. The buffer pool contains five buffers and each buffer stores one block of data. Memory accesses are by block ID. Assume the following series of memory accesses takes place:

5 2 5 12 3 6 5 9 3 2 4 1 5 9 8 15 3 7 2 5 9 10 4 6 8 5 For each of the following buffer pool replacement strategies, show the contents of the buffer pool at the end of the series, and indicate how many times a block was found in the buffer pool (instead of being read into memory).

Assume that the buffer pool is initially empty.

(a) First-in, first out.

(b) Least frequently used (with counts kept only for blocks currently in memory, counts for a page are lost when that page is removed, and the oldest item with the smallest count is removed when there is a tie).

(c) Least frequently used (with counts kept for all blocks, and the oldest item with the smallest count is removed when there is a tie).

(d) Least recently used.

(e) Most recently used (replace the block that was most recently accessed).