(D) 2 Pages with references.1. Under what circumstances do page faults occur? Describe in detail the actions taken by the operating system when a page fault occurs.2. Consider a system that uses

(D) 2 Pages with references.

1.    Under what circumstances do page faults occur? Describe in detail the actions taken by the operating system when a page fault occurs.

2.    Consider a system that uses pure demand paging.

a.   When a process first starts execution, how would you characterize the page-fault rate?

b.   Once the working set for a process is loaded into memory, how would you characterize the page-fault rate?

c.    Assume that a process changes its locality and the size of the new working set is too large to be stored in available free memory. Identify some options system designers could choose from to handle this situation.