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OS Interview Questions and Answers

In this article we have gathered the latest and most asked OS Interview Questions and Answers for both freshers and experienced. If you’re preparing for a job interview in the field of computer science, it’s crucial to have a solid understanding of operating systems. Whether you’re a seasoned computer science professional or just starting out, this guide will provide valuable insights into the world of operating systems and help you prepare for your next job interview with confidence. So, let’s dive in and explore the most important OS interview questions!

An Operating System (OS) is a computer program that manages hardware along with other software applications on a computer system. It provides a platform for system and application software to run and acts as an intermediary between the computer hardware and the user. When you turn on the device the operating system starts running and when you turn off the device it stops running. Some of the most commonly used Operating System in computers and mobile phones are Windows, Linux, Ubuntu, MAC OS X and Android.

OS Interview Questions and Answers

These OS Interview Questions will help job seekers to prepare well for the job interview and cross the panel discussion easily.

So let’s get started :

1. What is an operating system?
2. What is the main purpose of an operating system?
3. What is a real-time system?
4. What is kernel?
5. What is a virtual memory?
6. What do you mean by a process?
7. What is the use of paging in operating system?
8. What is the concept of demand paging?
9. What is a critical section in the operating system?
10. What is deadlock?
11. What are the necessary conditions for deadlock?
12. What is a thread?
13. What is FCFS?
14. What is SMP?
15. What is RAID? What are the different RAID levels?
16. What is fragmentation?
17. What is cache memory?
18. What is spooling?
19. What is Banker’s algorithm in OS?
20. What is a boot partition in OS?

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1. What is an operating system?

An operating system is a software program that allows computer hardware to communicate with and operate computer software. It is the most important part of computer system without OS the computer is like a box.


2. What is the main purpose of an operating system?

Operating systems exist for two main purposes. One is that it is designed to ensure that a computer system performs well by managing its computational activities. The second is that it provides an environment for the development and execution of programs.


3. What is a real-time system?

Real-time systems are used when rigid time requirements have been placed on the operation of a processor. It has well defined and fixed time constraints.


4. What is kernel?

Kernel is the core and most important part of a computer operating system. It connects applications to processing data and manages communication between software and hardware components.


5. What is a virtual memory?

Virtual memory is a very useful memory management technique that enables processes to be executed outside of memory. This technique is especially used when an executing program cannot fit in physical memory.


6. What do you mean by a process?

An executing program is known as a process. There are two types of processes:

  • Operating System Processes
  • User Processes

7. What is the use of paging in operating system?

Paging is used to solve the problem of external fragmentation in operating systems. This technology ensures that the data you need is available at the earliest.


8. What is the concept of demand paging?

Demand paging specifies that if an area of memory is not currently being used, it is moved to disk to make room for what the application needs.


9. What is a critical section in the operating system?

The critical section problem is an important issue to consider when designing an operating system. There are several ways to prevent a critical section problem from occurring. One is that each process must wait until the other has finished its critical section before starting its own. The second is to check the operating system for conflicts and give priority to one process over another.

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10. What is deadlock?

Deadlock is a specific situation or condition where two processes are waiting for each other to complete so that they can start. But this situation becomes the reason for hanging for both.


11. What are the necessary conditions for deadlock?

There are 4 necessary conditions to achieve a deadlock:

  • Mutual Exclusion: Only one process can use a resource at a time.
  • Hold and Wait: A process must be simultaneously holding at least one resource and waiting for at least one resource that is currently being held by some other process.
  • No Preemption: Once a process is holding a resource, then that resource cannot be taken away from that process until the process voluntarily releases it.
  • Circular Wait: A set of processes wait for each other in a circular turn.

12. What is a thread?

A thread is a basic unit of CPU utilization. In general, a thread is composed of a thread ID, program counter, register set, and the stack.


13. What is FCFS?

FCFS stands for first come, first served. It is a type of scheduling algorithm. In this scheme, if a process requests CPU first, it is allocated to CPU first. Its implementation is managed by a FIFO queue.


14. What is SMP?

SMP stands for Symmetric Multi-Processing. This is the most common type of multi-processor system. In this system, each processor runs an identical copy of the operating system, and these copies communicate with each other as needed.


15. What is RAID? What are the different RAID levels?

RAID stands for Redundant Array of Independent Disks. It is used to store the same data redundantly to improve the overall performance.

Following are the different RAID levels:

  • RAID 0 : Stripped Disk Array without fault tolerance
  • RAID 1 : Mirroring and duplexing
  • RAID 2 : Memory-style error-correcting codes
  • RAID 3 : Bit-interleaved Parity
  • RAID 4 : Block-interleaved Parity
  • RAID 5 : Block-interleaved distributed Parity
  • RAID 6 : P+Q Redundancy

16. What is fragmentation?

Fragmentation is a memory wastage. This reduces capacity and performance as space is used inefficiently.

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17. What is cache memory?

Cache memory is a small-sized memory that is volatile. A cache memory is usually much efficient because of its high access speed. Whenever the CPU wants to access any data, it first checks the cache memory. If the data is not there in cache memory, the CPU goes to the main memory.


18. What is spooling?

Spooling is normally associated with printing. When different applications want to send an output to the printer at the same time, spooling takes all of these print jobs into a disk file and queues them accordingly to the printer.


19. What is Banker’s algorithm in OS?

The Banker’s algorithm is a deadlock avoidance algorithm in OS. It was developed by Edsger Dijkstra. It is based on the algorithm in banking system where a bank never runs out of cash because bank does not allocate money in such a way that it can not satisfy the needs of a customer.


20. What is a boot partition in OS?

The boot partition in the OS is also known as the system partition. A boot partition is a disk partition that must exist and be configured correctly for the computer to operate. The boot partition contains the boot loader. It is the software responsible for booting the operating system.


We hope these OS Interview Questions help you in cracking your next Computer Science Interview.

All The Best!

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