30 Most Important Viva Questions for Operating System (BCA 2nd Semester)

If you are a BCA 2nd semester student preparing for Operating System (OS) practical viva, this post is for you. Below are 30 most commonly asked viva questions with clear, exam-oriented answers based on the Kurukshetra University (KUK) syllabus. These questions cover Process Management, CPU Scheduling, Deadlocks, Memory Management, and File Systems.

🔹 Basic Concepts

1. What is an Operating System?

An Operating System is system software that acts as an interface between the user and computer hardware. It manages hardware resources and provides services to application programs.

2. What are the main functions of an Operating System?

Main functions include process management, memory management, file management, device management, and security.

3. What is a process?

A process is a program in execution. It includes the program code, current activity, and allocated resources.

4. What is the difference between process and program?

A program is a passive set of instructions stored on disk, while a process is an active instance of a program currently being executed.

5. What is a thread?

A thread is the smallest unit of execution within a process. Multiple threads can exist within the same process and share resources.

🔹 CPU Scheduling

6. What is CPU scheduling?

CPU scheduling is the method used by the operating system to decide which process in the ready queue will be allocated the CPU next.

7. What is FCFS scheduling?

First Come First Serve (FCFS) is a non-preemptive scheduling algorithm where the process that arrives first gets executed first.

8. What is Round Robin scheduling?

Round Robin is a preemptive scheduling algorithm where each process gets a fixed time slice called time quantum in a cyclic order.

9. What is time quantum?

Time quantum is the fixed amount of CPU time allocated to each process in Round Robin scheduling.

10. What is context switching?

Context switching is the process of saving the state of a currently running process and loading the state of the next scheduled process.

🔹 Deadlocks

11. What is a deadlock?

A deadlock is a situation where two or more processes are blocked forever because each process is holding a resource and waiting for another resource.

12. What are the four necessary conditions for deadlock?

The four conditions are Mutual Exclusion, Hold and Wait, No Preemption, and Circular Wait.

13. What is deadlock prevention?

Deadlock prevention ensures that at least one of the necessary conditions for deadlock never holds true.

14. What is deadlock avoidance?

Deadlock avoidance dynamically checks resource allocation states to ensure that the system never enters an unsafe state.

15. What is Banker's Algorithm?

Banker’s Algorithm is a deadlock avoidance algorithm that checks whether granting a resource request keeps the system in a safe state.

🔹 Memory Management

16. What is memory management?

Memory management is the function of an OS that manages primary memory and controls allocation and deallocation of memory blocks.

17. What is paging?

Paging is a memory management technique where physical memory is divided into fixed-size frames and logical memory into pages.

18. What is fragmentation?

Fragmentation is memory wastage that occurs when free memory is broken into small pieces. It can be internal or external.

19. What is virtual memory?

Virtual memory allows execution of processes that may not be completely in main memory by using disk space as an extension of RAM.

20. What is a page fault?

A page fault occurs when a program tries to access a page that is not currently present in main memory.

🔹 File System & I/O

21. What is a file system?

A file system is a method used by the OS to store, organize, and manage files on storage devices.

22. What is a directory?

A directory is a structure that stores information about files such as file name, location, size, and type.

23. What is disk scheduling?

Disk scheduling is the method of deciding the order in which disk I/O requests are serviced.

24. What is FCFS disk scheduling?

In FCFS disk scheduling, disk requests are served in the order they arrive.

25. What is seek time?

Seek time is the time taken by the disk arm to move the read/write head to the required track.

🔹 Miscellaneous

26. What is multitasking?

Multitasking is the ability of an OS to execute multiple processes concurrently by rapidly switching between them.

27. What is multiprogramming?

Multiprogramming is the technique of keeping multiple programs in memory to maximize CPU utilization.

28. What is spooling?

Spooling is a process of temporarily holding data in a buffer or disk before sending it to an I/O device like a printer.

29. What is a semaphore?

A semaphore is a synchronization tool used to control access to shared resources in a multi-process environment.

30. What is the difference between preemptive and non-preemptive scheduling?

In preemptive scheduling, the OS can interrupt a running process, whereas in non-preemptive scheduling, a process runs until it finishes or blocks.

📌 Tip: Practice explaining these answers in your own words during viva. For PYQs, notes, and practical files, visit: PyQHub – Previous Year Questions Hub