Question

What is validity fault?

Answer 1

Validity fault is the result of non setting of valid bits in main memory at the time of refererring a page by a process. This happens when the pages are available outside the virtual address space of a process or the pages are the part of the virtual address space where the physical address space is assigned to it.

The setting the valid bit of the page is the process of handling validity fault by the way of clearing the modify bit and reclaculating the process priority.