1. Page replacement algorithms are used in:
A) Contiguous memory allocation
B) Virtual memory systems
C) Disk scheduling
D) File allocation
B) Virtual memory systems
2. Page replacement is required when:
A) Page size is large
B) A page fault occurs and no free frame is available
C) CPU is idle
D) Disk is full
B) A page fault occurs and no free frame is available
3. Which page replacement algorithm replaces the oldest page?
A) LRU
B) Optimal
C) FIFO
D) Clock
C) FIFO
4. Which page replacement algorithm gives the minimum number of page faults?
A) FIFO
B) LRU
C) Optimal
D) Clock
C) Optimal
5. Which algorithm requires future knowledge of page references?
A) FIFO
B) LRU
C) Optimal
D) Clock
C) Optimal
6. LRU replaces the page that:
A) Was used least recently
B) Was loaded first
C) Has smallest page number
D) Is most recently used
A) Was used least recently
7. Which algorithm can be implemented using a stack?
A) FIFO
B) LRU
C) Optimal
D) Random
B) LRU
8. Which page replacement algorithm suffers from Belady’s anomaly?
A) FIFO
B) LRU
C) Optimal
D) Clock
A) FIFO
9. Belady’s anomaly refers to:
A) Increase in frames reduces page faults
B) Increase in frames increases page faults
C) Decrease in frames increases faults
D) No relation to frames
B) Increase in frames increases page faults
10. Which page replacement algorithms are stack algorithms?
A) FIFO and Optimal
B) FIFO and LRU
C) LRU and Optimal
D) Clock and FIFO
C) LRU and Optimal
11. Stack algorithms do NOT suffer from:
A) Page faults
B) Thrashing
C) Belady’s anomaly
D) Page replacement
C) Belady’s anomaly
12. The Clock algorithm is also known as:
A) FIFO
B) Second chance algorithm
C) Optimal algorithm
D) Stack algorithm
B) Second chance algorithm
13. In Clock algorithm, a page is replaced when:
A) Use bit is 0
B) Use bit is 1
C) Page number is highest
D) Page is oldest
A) Use bit is 0
14. Which page replacement algorithm is easiest to implement?
A) Optimal
B) LRU
C) FIFO
D) Clock
C) FIFO
15. Which algorithm is commonly used in real systems as an approximation of LRU?
A) Optimal
B) FIFO
C) Clock
D) Random
C) Clock
16. Page fault frequency is:
A) Number of pages in memory
B) Rate at which page faults occur
C) CPU execution speed
D) Disk access time
B) Rate at which page faults occur
17. Which factor directly affects page fault rate?
A) CPU speed
B) Disk rotation speed
C) Number of frames
D) Instruction size
C) Number of frames
18. Thrashing is most likely when:
A) Page fault rate is low
B) CPU utilization is high
C) Page fault rate is very high
D) Disk is idle
C) Page fault rate is very high
19. Which technique helps control thrashing?
A) FIFO scheduling
B) Working set model
C) Round Robin
D) Disk caching
B) Working set model
20. Working set model is based on:
A) Total pages in memory
B) Recent page references
C) CPU scheduling
D) Disk access time
B) Recent page references
21. Which of the following page replacement algorithms never replaces a heavily used page?
A) FIFO
B) Optimal
C) LRU
D) Random
C) LRU
22. Increasing number of frames usually:
A) Increases page faults always
B) Decreases page faults (except FIFO)
C) Has no effect
D) Stops paging
B) Decreases page faults (except FIFO)
23. Which algorithm is theoretical and not practically implementable?
A) FIFO
B) LRU
C) Optimal
D) Clock
C) Optimal
24. Page replacement decisions are made by:
A) CPU
B) Compiler
C) Operating system
D) MMU only
C) Operating system
25. Which of the following best defines a stack algorithm?
A) Uses stack data structure
B) Pages in memory are always subset with more frames
C) Uses FIFO queue
D) Based on priority
B) Pages in memory are always subset with more frames