BPSC TRE – OS: Deadlocks, Memory Management & Virtual Memory

Question 36

MCQ · Single Correct 1 mark

Which page replacement algorithm approximates LRU using a single Reference Bit and a circular queue of pages?

A Clock (Second-Chance) Algorithm B FIFO Algorithm C Optimal Algorithm D More than one of the above E None of the above

Question 37

MCQ · Single Correct 1 mark

What is the Working-Set Model used for in operating systems?

A Preventing Thrashing by defining the set of pages a process actively referenced in recent time window $\delta$ B Calculating network socket bandwidth C Sorting files in file systems D More than one of the above E None of the above

Question 38

MCQ · Single Correct 1 mark

In virtual memory, what is Copy-on-Write (COW)?

A Writing file backups to cloud servers automatically B An optimization technique where parent and child processes initially share the same physical pages upon fork(), copying a page only when modified C Creating duplicate page tables on every read operation D More than one of the above E None of the above

Question 39

MCQ · Single Correct 1 mark

Why is the Least Recently Used (LRU) algorithm immune to Belady's Anomaly?

A Because LRU uses future reference knowledge B Because LRU belongs to the class of Stack Algorithms C Because LRU uses fixed page sizes D More than one of the above E None of the above

Question 40

MCQ · Single Correct 1 mark

Calculate Effective Access Time (EAT) for Demand Paged memory given: Memory Access Time = 200 ns, Page Fault Service Time = 8 ms (8,000,000 ns), Page Fault Rate $p = 0.001$.

A 208 ns B 800 ns C $8,199.8 ns (\approx 8.2 microseconds)$ D More than one of the above E None of the above