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Commonly Asked Operating System Interview Questions

  • Post last modified:May 13, 2022
  • Reading time:15 mins read
  • Post category:Interview

Operating system is a core subject in computer science courses, When you are giving interview in IT Sector, there are several chances, you may be asked operating system interview questions. In this article I have listed some top operating system questions which is commonly asked.

Operating System

Operating system is an essential part of computer system which is responsible for managing and handling computing resources. It prioritize and co-ordinate all activities across the computer system. It acts as a middleware between computer user and computer hardware.

I have compiled top 30 of most asked interview question which may help you to crack your interview, It covers all questions from basic to advances for freshers as well as experienced professionals.
And we wish you get soon your dream job.

Basic Questions

1. What is an operating system?

Operating System basically a software program that manages and handles all resources of a computer such as hardware and software. It acts as an interface between computer user and hardware.

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

It manages hardware parts of a computer like keyboard, mouse, processor, memory etc.
It manages resources. Resources means printer, scanner, projector etc.

3. What are the 5 operating systems.

The most 5 used operating system is: Windows, MAC, Linux , Apple iOS and Google Android

4. What is kernel?.

Windows, Mac, Linux or Android operating system, has a core program called ‘Kernel‘ , It is heart of operating system. Kernel is just a computer program which controls everything that happens on computer. When you boot your system, it loads first then it manages everything else. It also manages communication between software and hardware.

5. What is virtual memory?

Virtual Memory is memory management technique which enables execution of process in isolated environment outside memory

6. What are real-time systems?

A real-time operating system (RTOS) is a special-purpose operating system used in computers that has strict time constraints for any job to be performed.

7. What is a thread?

A thread is the smallest unit of processing that can be performed in an OS. In most modern operating systems, a thread exists within a process – that is, a single process may contain multiple threads.

8. What are time sharing systems?

In a Time sharing system, the CPU executes multiple jobs by switching among them, also known as multitasking. This process happens so fast that users can actually interact with each program while it is running.

9. Give some benefits of multithreaded programming.

– there is an increased responsiveness to the user
– resource sharing within the process
– economy
– utilization of multiprocessing architecture

10. What is the basic function of paging?

Paging is a storage mechanism that allows OS to retrieve processes from the secondary storage into the main memory in the form of pages. In the Paging method, the main memory is divided into small fixed-size blocks of physical memory, which is called frames. Paging is used for faster access to data, and it is a logical concept.

11. What is a socket?

A socket provides a connection between two applications. Each endpoint of a communication is a socket.

12. What is multitasking?

Multitasking is a logical extension of multiprogramming system that supports multiple programs to run concurrently. In multitasking more than one task are executed at the same time. In this technique the multiple tasks, also known as processes, share common processing resources such as a CPU

13. What is caching?

Caching is storing data in a separate disk (very fast speed disk). The data which is to be used many times results in wastage of time if it is in hard disk, but storing the data in cache reduces this time wastage.

14. What is an Assembler?

An assembler is a type of computer program that interprets software programs written in assembly language into machine language, code and instructions that can be executed by a computer.

15. What is GUI?

GUI stands for Graphical User Interface. It is a visual representation of communication presented to the user for easy interaction with the machine

16. What is piping?

Piping also known as plumbing describe a feature found in operating systems where the output of one program is sent as input to another program. This feature is useful for when a user needs data from one program and does not want to retype all the output.

17. What are the advantages of a multiprocessor system?

A multiprocessor system is a system in which two or more CPU (Central processing systems) are used. In this type of system two or more processes can be processed in parallel i.e. at the same time interval.
Advantage – High Throughput, Less electricity usage, High Reliability, Economical

18. What is booting in OS?

Booting is the process of starting a computer as initiated via hardware such as a button or by a software command

19. What is BIOS?

BIOS(Basic Input/Output System) is the program a computer’s microprocessor uses to start the computer system after it is powered on. It also manages data flow between the computer’s operating system (OS) and attached devices, such as the hard disk, video adapter, keyboard, mouse and printer.

20. Concept of the batched operating systems?

This type of operating system does not interact with the computer directly. There is an operator which takes similar jobs having the same requirement and group them into batches. It is the responsibility of the operator to sort jobs with similar needs.

21. What are components of operating system?

(1.)Process Management (2.)File Management
(3.)Network Management (4.)Main Memory Management (5.)Secondary Storage Management (6.)I/O Device Management (7.)Security Management (8.)Command Interpreter System

22. What are the types of thread in OS?

1.Kernel level thread.
2.User-level thread.

23. Describe Banker’s algorithm?

The Banker algorithm, sometimes referred to as the detection algorithm, is a resource allocation and deadlock avoidance algorithm developed by Edsger Dijkstra that tests for safety by simulating the allocation of predetermined maximum possible amounts of all resources, and then makes an “s-state” check to test for possible deadlock conditions for all other pending activities, before deciding whether allocation should be allowed to continue.

24. What are overlays?

Overlaying is defined as “the process of inserting a block of computer code or other data into internal memory, replacing what is already there.” It is a method that permits applications to be larger than the primary memory.

25. What is fragmentation?

Fragmentation is an unwanted problem in the operating system in which the processes are loaded and unloaded from memory, and free memory space is fragmented. Processes can’t be assigned to memory blocks due to their small size, and the memory blocks stay unused.

26. How Does Swapping Result In Better Memory Management?

During regular intervals that are set by the operating system, processes can be copied from main memory to a backing store, and then copied back later. Swapping allows more processes to be run that can fit into memory at one time.

27. Give An Example Of A Process State.

New State – means a process is being created
Running – means instructions are being executed
Waiting – means a process is waiting for certain conditions or events to occur
Ready – means a process is waiting for an instruction from the main processor
Terminate – means a process is done executing

28. What Are Some Pros And Cons Of A Command Line Interface?

Pros- One of the main advantages of a command line interface is that it allows users to type in commands that can produce immediate results. Those familiar with command-lines find this method quick and simple.
Cons- the main disadvantage of a command-line interface is that users must be familiar with the commands in order to maximize the above advantages. In that sense, there can be a fairly steep learning curve if you’re new to programming.

29. 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.

30. What Is Nos?

A network operating system(NOS) is software that connects multiple devices and computers on the network and allows them to share resources on the network


We have reached to end of operating system interview questions. In simple words, OS is heart of computer, without Operating system a user can not communicate with the system. We have covered the important questions still there is no guarantee that interviewer will be asking exact same questions as detailed in this articles. The purpose of these questions to give you a brief idea about what type of question may be asked.
If you have liked the article or have any suggestion please leave them in the comment section below.

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