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Operating System Unit 3 – CPU Scheduling and Deadlock: important questions for AKTU

Unit 3 (CPU Scheduling and Deadlock) questions that AKTU repeats most often. This unit carries about 36 marks per paper. Start with the repeated questions, then the most asked topics.

Most repeated Unit 3 questions

  • A system shares 9 tape drives. Current allocation and maximum requirement: P1(alloc=3, max=7), P2(alloc=1, max=6), P3(alloc=3, max=5). Which of the following best describes current state: 1. Safe, Deadlocked 2. Safe, Not Deadlocked 3. Not Safe, Deadlocked 4. Not Safe, Not deadlocked. Explain. (7 marks, 2025, Deadlock) – also asked in 2018, 2019, 2022, 2023, 2024
  • Explain the process concept in detail with its states and state transition diagram. (7 marks, 2025, CPU Scheduling) – also asked in 2019, 2022, 2023, 2024
  • Two semaphores S1 and S2 are both initialized to 1. Process P1 executes wait(S1); wait(S2); and P2 executes wait(S2); wait(S1);. Explain how a deadlock may occur and under what sequence. (7 marks, 2025, Deadlock) – also asked in 2018, 2022, 2023, 2024

Most important Unit 3 topic

  • CPU Scheduling (Unit 3: CPU Scheduling and Deadlock) – asked 22 times in 2018, 2019, 2022, 2023, 2024, 2025

Most asked Unit 3 topics

  • CPU Scheduling – asked 22 times
  • Deadlock – asked 14 times
  • Threads and Management – asked 1 times

More Unit 3 previous year questions

  • A system has 3 processors and 5 programs ready for execution. In how many ways can the processors be assigned to the programs assuming each processor executes one program at a time? (2 marks, 2025, CPU Scheduling)
  • List three components stored in a PCB. (2 marks, 2025, CPU Scheduling)
  • Consider the set of processes with arrival time (in milliseconds), CPU burst time (in milliseconds), and priority (0 is the highest priority) shown below. P1(AT=0,BT=11,Pri=2), P2(AT=5,BT=28,Pri=0), P3(AT=12,BT=2,Pri=3), P4(AT=2,BT=10,Pri=1), P5(AT=9,BT=16,Pri=4). Draw the Gantt chart and find average waiting time using preemptive priority scheduling algorithm. (7 marks, 2025, CPU Scheduling)
  • Compare and contrast FCFS, SJF, and Round Robin scheduling algorithms. (7 marks, 2025, CPU Scheduling)
  • Define a process state? (2 marks, 2024, CPU Scheduling)

Unit 3 syllabus topics

  • CPU Scheduling
  • Threads and Management
  • Deadlock