Consider the virtual page reference string $$$1,2,3,2,4,1,3,2,4,1$$$
On a demand paged virtual memory system running on a computer system that has main memory size of $$3$$ page frames which are initially empty. Let $$LRU,$$ $$FIFO$$ and $$OPTIMAL$$ denote the number of page faults under the corresponding page replacement policy. Then

Consider a disk system with $$100$$ cylinders. The requests to access the cylinders occur in following sequence:
$$4, 34, 10, 7, 19, 73, 2, 15, 6, 20$$
Assuming that the head is currently at cylinder $$50,$$ what is the time taken to satisfy all requests if it takes $$1$$ $$ms$$ to move from one cylinder to adjacent one and shortest seek time first policy is used?

In which one of the following page replacement policies, Belady’s anomaly may occur?

Consider a system with 4 types of resources R1 (3 units), R2 (2 units), R3 (3 units), R4 (2 units). A non-preemptive resource allocation policy is used. At any given instance, a request is not entertained if it cannot be completely satisfied. Three processes P1, P2, P3 request the sources as follows if executed independently. Which one of the following statements is TRUE if all three processes run concurrently starting at time t = 0?