Question

Computer architecture

Question 20 25 pts A program has run out of memory space and needs to evict pages. When looking at the Page Table, what is the presente page reclament Rank the cases. Dirty, Reference-0 (Choose) 1st choice 4th choice 3rd choice 2nd choice Dirtyo, Reference-1 Dirty-1, Reference Choose) Choose) Dirty-1, Reference-1

Answer 1

Answer:

Dirty = 0; Reference = 0 ;; 4th Choice

Dirty = 0; Reference = 1 ;; 2nd Choice

Dirty = 1; Reference = 0 ;; 3rd Choice

Dirty = 1; Reference = 1 ;; 1st Choice

Explanation:

Reference Bits in Page table denotes if the page is recently used or not

If Reference bit is 1: The page was recently referenced.

If Reference bit is 0: The page has not been recently referenced.

And the high priority will be gone to the page which is recently referenced.

Dirty Bit denotes if the page has been clean or dirty. Dirty means something is written worth backing up.

If the Dirty bit is 1: Data is “dirty”, has been written.

If the Dirty bit is 0: Data is “clean”, same as when it was loaded.

Priority will be given to the written case.