Operating Systems · Question 21 · Medium
Operating Systems question 21
A system has 3 page frames, all initially empty. For the page reference string 1, 3, 0, 3, 5, 6, 3, 1, 0, 5, 3, 6, how many page faults occur with the Optimal page-replacement algorithm?
- 7
- 6
- 9
- 10
Answer and explanation
Answer: A. 7
Explanation: 1, 3, 0 fault. 3 hits. 5 faults and replaces 0 (used farthest ahead). 6 faults and replaces 5. 3 and 1 hit. 0 faults and replaces 1 (never used again). 5 faults and replaces 0. 3 and 6 hit. Total = 7.
Previous: In UNIX and Linux, which system call creates a new process that is a copy of… · Next: Process (arrival time, burst time) in ms: P1 (0, 7), P2 (2, 4), P3 (4, 1), P4…
Practise operating systems
Try a fresh set of operating systems questions with an explanation after every answer, free and without signing up: Operating Systems practice. Or sit a full placement mock test.
More operating systems questions
- Which page-replacement algorithm gives the lowest possible number of page…
- Belady's anomaly, where giving a process more page frames can increase its…
- In UNIX and Linux, which system call creates a new process that is a copy of…
- Process (arrival time, burst time) in ms: P1 (0, 7), P2 (2, 4), P3 (4, 1), P4…
- How many times is "A" printed when this C program runs? Assume every fork()…
- A disk has cylinders 0 to 199 and the head is at cylinder 50. The request…
- A system uses 32-bit logical addresses, a page size of 4 KB and 4-byte…
- Process (arrival time, burst time, priority) in ms: P1 (0, 5, 3), P2 (1, 3…
- A system has three resource types. Available = (1, 2, 2). Process | Allocation…
- Memory access time is 200 ns, and servicing a page fault takes 8 ms. If 1 in…
More technical & programming practice
Computer Networks · Software Engineering · Cloud & DevOps · GenAI Basics · Pseudo-code · C Programming · Java · Python
LogicWiz Exams home · All practice topics · Placement mock tests · Daily 10 challenge