Question :

(a) In the demand paging system, when a process tries to access a page that was not brought into memory, a page fault occurs that involves a series of actions. The diagram shows the steps involved in dealing with this situation. Give a clear description of this page fault situation and define the steps numbered 1 to 6.

(b) Consider the following page-reference string:

1,2,3,4,2,1,5,6,2,1,2,3,7,6,3,2,1,2,3,6

If a system consists of 3 frames, how many page faults will occur for the following replacement algorithms?

i) FIFO algorithm
ii) Optimal algorithm
iii) LRU algorithm

(c) Describe whether it is possible to implement the algorithm that results in the lowest page-fault rate from (b)?