Intermediate
Operating Systems
Q75 / 100
What is the purpose of a "dirty bit" associated with a page table entry?
Correct! Well done.
Incorrect.
The correct answer is B) It records whether a page has been modified since it was loaded, so the OS knows whether it must be written back to disk before being evicted
B
Correct Answer
It records whether a page has been modified since it was loaded, so the OS knows whether it must be written back to disk before being evicted
Explanation
When a page replacement algorithm selects a victim page, the dirty (modified) bit tells the OS whether the page's contents differ from the copy on disk. Clean pages can simply be discarded, while dirty pages must be written back first, which is more costly.
Progress
75/100