45 Most Asked Operating System Interview Questions (With Sample Answers and Tips)

Table of Contents

1. Most Asked Operating System Interview Questions and Answers
2. Basic Operating System Interview Questions
3. Intermediate Level Operating System Interview Questions
4. Advanced Operating System Interview Questions
5. Operating System Viva Questions
6. Tips to Prepare for Operating System Interview
   
   

Operating System interview questions are common in software and computer science job interviews.

But first, what is an OS?

An operating system (OS) is the software that connects hardware with applications. It keeps your computer running and manages system resources.

The first real OS was GM-NAA I/O. It was developed in 1956 by General Motors and North American Aviation for the IBM 704. This system was built to automate batch processing. Later, operating systems like UNIX and Microsoft Windows became the foundation of modern computing.

Because OS concepts are part of every IT job, knowing them is important. This blog covers the 45 most asked operating system interview questions with sample answers and tips.

Most Asked Operating System Interview Questions and Answers

Here is a list of the most frequently asked Operating System interview questions and answers. These are commonly seen in job interviews and help test your core understanding of OS concepts.

1. What are the main types of operating systems, and where are they used?

They want to check your real-world understanding, not just definitions.

Sample answer

"There are several types of OS.

• Batch operating systems are used for repetitive jobs like payroll processing.
• Real-time OS is used in systems like medical devices where timing is critical.
• Distributed OS runs on networked computers, common in cloud platforms.
• Multiprogramming and time-sharing OS are used in desktops and servers.
• Mobile operating systems like Android and iOS run on smartphones."

Tip – Give 1 to 2 examples for each OS type.

2. What is the difference between multitasking, multithreading, and multiprocessing?

This checks your grasp on system-level performance management.

Sample answer

"Multitasking means switching between tasks so fast it looks like they run at the same time.

Multithreading means a single program runs multiple threads in parallel.

Multiprocessing means multiple CPUs or cores handle multiple tasks at the same time.

While multitasking happens on one CPU, multiprocessing needs more than one."

Tip – Use simple analogies like multiple chefs (multiprocessing) vs. one chef switching tasks (multitasking).

3. What is a process? How does it differ from a thread in real-world applications?

Often asked to test how well you understand execution flow.

Sample answer

"A process is an independent program under execution with its own memory. A thread is a smaller unit within a process that shares memory with other threads. For example, a browser is a process – and each tab runs as a separate thread. Threads are faster and lighter but can cause issues if not managed well."

Tip – Try to relate to applications like web browsers or games that use multiple threads.

4. What is virtual memory, and how does it help with performance?

This tests your understanding of memory management.

Sample answer

"Virtual memory lets the OS use part of the hard drive as additional RAM. When the system runs out of physical memory, it shifts inactive data to disk storage, freeing up space for active tasks. This prevents crashes and lets larger applications run even with limited RAM."

Tip – You can mention the concept of swap space or page file if you are comfortable with it.

5. What causes a deadlock, and how can it be resolved in a system?

Interviewers use this to check how you handle system-level blocks.

Sample answer

"A deadlock occurs when two or more processes are stuck waiting for each other’s resources. It happens when four conditions are met: mutual exclusion, hold and wait, no preemption, and circular wait. It can be resolved by avoiding circular wait, using resource ordering, or detecting and recovering from deadlocks using algorithms."

Tip – You don’t need to list all four conditions unless asked, but knowing them adds depth.

6. What is context switching? How does it affect performance?

Very common question to check your grasp on multitasking and scheduling.

Sample answer

"Context switching is when the CPU stops one process and switches to another. It saves the current process’s state and loads the new one. This lets multiple processes share the CPU. However, frequent context switches add overhead and reduce performance because saving and loading states takes time."

Tip – Mention that it is necessary for multitasking but should be minimized when possible.

7. What is a zombie process, and how do you handle it in production?

This is a favorite in Linux-based interviews.

Sample answer

"A zombie process is one that has finished executing but still has an entry in the process table. It happens when the parent process doesn’t read its exit status. In production, I monitor such processes with ps -ef and use wait() in the parent or re-parent them to init so the system can clean them up."

Tip – You don’t have to go deep unless asked. Just knowing the concept is a good start.

8. Which OS do you prefer working on and why?

This gives insight into your comfort level and preferences.

Sample answer

"I prefer working on Linux because it gives me more control, better performance tools, and scripting flexibility. It is reliable for servers and development work. I have used tools like crontab, systemctl, and journalctl regularly. I am also comfortable with Windows for user applications, but Linux is my go-to for backend and DevOps work."

Tip – Be honest. Don’t say Linux or Windows just to sound smart – share your actual workflow.

Basic Operating System Interview Questions

These are foundational interview questions for OS-related job roles that recruiters ask to test your basic understanding. They are simple but important for building deeper knowledge.

1. What are the key functions of an operating system?
2. What is a kernel, and what does it control?
3. How does the OS handle memory allocation for applications?
4. What is the difference between user mode and kernel mode?
5. What is a file system, and how does an OS manage files?
6. What are device drivers, and why are they important?
7. What is a shell in Linux or UNIX systems?
8. What is the difference between a program and a process?
9. What is IPC (Inter-process Communication), and why is it needed?
   

Intermediate Level Operating System Interview Questions

This section covers operating system interview questions that dig deeper into core concepts. They are commonly asked in technical interviews.

1. What is thrashing, and how can it be minimized?
2. Explain demand paging with an example.
3. How do FIFO, LRU, and Optimal page replacement algorithms differ?
4. What are semaphores, and how do they help prevent race conditions?
5. Explain the difference between internal and external fragmentation.
6. What is process scheduling? Describe Round Robin and SJF.
7. How does the OS manage concurrency in multi-threaded applications?
8. What are signals in Unix/Linux, and how are they handled?
9. What is the difference between paging and segmentation?

Advanced Operating System Interview Questions

Here are complex, scenario-based operating system interview questions focused on system architecture, security, and modern OS features.

1. What is a real-time operating system (RTOS), and where is it used?
2. What is a microkernel? How does it differ from a monolithic kernel?
3. How does an OS manage system security and access control?
4. What is the role of the OS in cloud computing environments?
5. What is a hypervisor, and how is it different from an OS kernel?
6. Explain how containers achieve isolation at the OS level.
7. How does the OS manage disk scheduling in high I/O workloads?
8. What is RAID, and how is it handled by the OS?
9. What is symmetric multiprocessing (SMP), and how is it different from clustering?

Operating System Viva Questions

These concept-based operating system viva questions are commonly asked in academic viva rounds or rapid-fire technical interviews.

1. What is a bootstrap program?
2. What is the difference between logical and physical address?
3. What is a trap, and how is it different from an interrupt?
4. What are overlays in OS?
5. What is the function of the scheduler?
6. Name any two deadlock avoidance techniques.
7. What is context switching in a single-core CPU?
8. What are the necessary conditions for a deadlock?
9. What is the role of a fence register?
10. What is the difference between a soft real-time system and a hard real-time system?
    

Tips to Prepare for Operating System Interview

Now that you have a list of the most commonly asked operating system interview questions, here are a few practical tips to help you prepare more confidently for your interviews.

• Focus on core topics like memory management, process scheduling, and deadlocks.
• Practice explaining OS concepts aloud in simple language.
• Prepare one real example where you solved a performance or system issue.
• Solve previous interview questions for OS and write mock answers.
• Read OS-related articles or blogs to stay updated.
• Review common Linux commands if applying for backend or dev roles.
• Watch short YouTube explainers or visualize using diagrams if you are stuck on concepts.

FAQs

What are the 5 functions of OS?

• Memory Management – Allocating and freeing memory.
• Process Management – Handling running processes and threads.
• File System Management – Organizing data on storage.
• Device Management – Controlling hardware components.
• Security & Access Control – Protecting system data and resources.

Are interview questions for OS tough?

Interview questions for OS can be tricky if you are not clear on the basics. The good news is that most companies focus on core concepts and real-world understanding – not memorization. With practice, they become easier.

What is the average salary for OS-related job roles in India?

There are many roles where strong operating system skills are essential. Here’s a look at some top job titles and their average salaries, based on data from AmbitionBox.

Which top companies are hiring OS specialists?

Many tech companies actively hire professionals with strong operating system skills – especially for backend, infrastructure, and embedded roles. Top recruiters include –

• Google
• Amazon
• Microsoft
• Intel
• AMD
• Cisco
• TCS
• Infosys
• Wipro
• Capgemini

Is learning operating systems still important for modern tech jobs?

Yes, absolutely. Understanding how an operating system works helps you write more efficient code. OS concepts are especially important in backend development, DevOps, system design, embedded systems, and cybersecurity roles.