Dirty bit Vs. Valid bit?

Question

Please clarify the difference between the DIRTY BIT and the VALID BIT in virtual memory?

Comments

Here is a similar question on caches, that might be helpful.

Answer 1

valid / invalid bit is used to identify that particular page is in memory or not . and

dirty bit tells status of page means it is modified by processor or not.

Comments

any1 knows some thing extra on these bits let me know .