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Operating System (BCS401) AKTU previous year questions 2018–2025

Every Operating System question from 6 AKTU papers, tagged by unit, topic and marks. A few recent questions from each unit are listed below; open the page to filter by unit, topic or mark type.

Unit 1: Introduction to Operating Systems – AKTU PYQs

  • What are the primary functions of an operating system? (2 marks, 2025, OS Functions and Structure)
  • Discuss the differences between Batch, Interactive, and Time Sharing Operating Systems with real-world applications. (7 marks, 2025, Classification of Operating Systems)
  • What is the primary function of an operating system? (2 marks, 2024, OS Functions and Structure)
  • Define a batch processing system? (2 marks, 2024, Classification of Operating Systems)
  • Compare and contrast time-sharing and multiprogramming operating system concepts? (7 marks, 2024, Classification of Operating Systems)

Unit 2: Concurrent Processes – AKTU PYQs

  • What is the difference between a process and a program? (2 marks, 2025, Process Concept and Concurrency)
  • In a Producer-Consumer system, the buffer size is 4. If Producer produces 6 items and Consumer consumes 3, find the number of items in the buffer at the end. (2 marks, 2025, Process Concept and Concurrency)
  • A process executes the following code: fork(); fork(); fork(); How many processes are created in total, including the original? (2 marks, 2025, Inter Process Communication)
  • Define the Critical Section Problem and list the conditions that a solution must satisfy. (7 marks, 2025, Mutual Exclusion)
  • Discuss the limitations of Dekker's and Peterson's solutions when applied to modern multiprocessor architectures. (7 marks, 2025, Mutual Exclusion)

Unit 3: CPU Scheduling and Deadlock – AKTU PYQs

  • 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)
  • Explain the process concept in detail with its states and state transition diagram. (7 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)

Unit 4: Memory Management – AKTU PYQs

  • What is the purpose of a page replacement algorithm? (2 marks, 2025, Virtual Memory)
  • In optimal page replacement algorithm, information about all future page references is available to the OS. A modification: OS correctly predicts only up to next 4 page references. A process accesses pages: 1, 3, 2, 4, 2, 3, 1, 2, 4, 3, 1, 4. If the system has three memory frames that are initially empty, find the number of page faults. (7 marks, 2025, Virtual Memory)
  • Discuss multiprogramming with variable partitions and how it improves memory utilization. (7 marks, 2025, Basic Memory Management)
  • Consider a demand paging memory management system with 32-bit logical address, 20-bit physical address, and page size of 2048 bytes. Assuming that the memory is byte addressable, what is the maximum number of entries in the page table? (7 marks, 2025, Virtual Memory)
  • Define a resident monitor? (2 marks, 2024, Basic Memory Management)

Unit 5: I/O Management and File Systems – AKTU PYQs

  • Explain file directories and directory structures in operating systems. (7 marks, 2025, File System)
  • Consider a disk queue with requests for I/O to blocks on cylinders 47, 38, 121, 191, 87, 11, 92, 10. The C-LOOK scheduling algorithm is used. The head is initially at cylinder number 63, moving towards larger cylinder numbers on its servicing pass. The cylinders are numbered from 0 to 199. Calculate the total head movement (in cylinders) required to service these requests. (7 marks, 2025, Disk Scheduling)
  • Discuss RAID 0, RAID 1, and RAID 5 in detail. (7 marks, 2025, Disk Scheduling)
  • Define an I/O subsystem? (2 marks, 2024, I/O Management)
  • Compare and contrast different disk storage technologies, such as HDDs and SSDs? (7 marks, 2024, Disk Scheduling)