GATE CS 2014 Set 3 — Question 30

NAT+1 / -0EasyPage Replacement AlgorithmsMemory ManagementOperating System

Operating System → Memory Management → Page Replacement Algorithms

Last updated 5 September 2026

Question

4, 7, 6, 1, 7, 6, 1, 2, 7, 2

Correct answer 6 to 6 Solution We have 3 page frames and use the LRU policy. The reference string is: 4, 7, 6, 1, 7, 6, 1, 2, 7, 2. 1. Ref 4 : Miss. Frames: [4, -, -]. Faults: 1. 2. Ref 7 : Miss. Frames: [4, 7, -]. Faults: 2. 3. Ref 6 : Miss. Frames: [4, 7, 6]. Faults: 3. 4. Ref 1 : Miss. Replace LRU (4). Frames: [1, 7, 6]. Faults: 4. 5. Ref 7 : Hit. Update LRU. Frames: [1, 6, 7] (7 is MRU). Faults: 4. 6. Ref 6 : Hit. Update LRU. Frames: [1, 7, 6] (6 is MRU). Faults: 4. 7. Ref 1 : Hit. Update LRU. Frames: [7, 6, 1] (1 is MRU). Faults: 4. 8. Ref 2 : Miss. Replace LRU (7). Frames: [2, 6, 1]. Faults: 5. 9. Ref 7 : Miss. Replace LRU (6). Frames: [2, 7, 1]. Faults: 6. 10. Ref 2 : Hit. Update LRU. Frames: [7, 1, 2] (2 is MRU). Faults: 6. Total page faults = 6. Turn this into a strength. Explore AI-powered practice and doubt support with Success Tracker.

Review answer and solution without JavaScript

Interactive answer checking needs JavaScript. The published solution is available below.

Correct answer 6 to 6 Solution We have 3 page frames and use the LRU policy. The reference string is: 4, 7, 6, 1, 7, 6, 1, 2, 7, 2. 1. Ref 4 : Miss. Frames: [4, -, -]. Faults: 1. 2. Ref 7 : Miss. Frames: [4, 7, -]. Faults: 2. 3. Ref 6 : Miss. Frames: [4, 7, 6]. Faults: 3. 4. Ref 1 : Miss. Replace LRU (4). Frames: [1, 7, 6]. Faults: 4. 5. Ref 7 : Hit. Update LRU. Frames: [1, 6, 7] (7 is MRU). Faults: 4. 6. Ref 6 : Hit. Update LRU. Frames: [1, 7, 6] (6 is MRU). Faults: 4. 7. Ref 1 : Hit. Update LRU. Frames: [7, 6, 1] (1 is MRU). Faults: 4. 8. Ref 2 : Miss. Replace LRU (7). Frames: [2, 6, 1]. Faults: 5. 9. Ref 7 : Miss. Replace LRU (6). Frames: [2, 7, 1]. Faults: 6. 10. Ref 2 : Hit. Update LRU. Frames: [7, 1, 2] (2 is MRU). Faults: 6. Total page faults = 6.

Continue learning with Success Tracker

Use Success Tracker to ask about the reasoning, then try another GATE CS question to check your understanding.

AI-powered practice· Unlimited practice on eligible plans

PYQs with solutions: Attempt available previous-year questions, then compare your reasoning with the worked solution. Coverage varies by stream.
Practice that adapts: Choose a topic, work on weaker areas and bookmark questions to revisit. Your attempts feed your progress tracking.
AI doubt support: Ask follow-up questions about a step or concept while practising, instead of stopping at the final answer.

Unlimited practice is available on eligible plans. Free practice and AI usage have limits; check the current plan allowances before choosing.

This page stays readable without an account. AI responses can be wrong; check them against the solution and source material.