Operating system technical interview questions and answers help students and job seekers understand core computing concepts that are essential for technical interviews. The operating system acts as a bridge between hardware and software, making it one of the fundamental subjects tested in campus placement interviews. Recruiters frequently ask questions about process management, memory allocation, deadlocks, scheduling algorithms, threads, file systems, and OS architecture. These OS interview questions appear repeatedly in companies like TCS, Wipro, Infosys, Cognizant, Capgemini, and Accenture. This guide explains the most commonly asked OS interview questions with easy-to-understand answers, practical examples, and simple definitions. Whether you are preparing for your first job, a technical round, or a written placement test, understanding OS concepts will help you perform confidently. You can also practice mock questions or download PDFs to strengthen your preparation.
Showing 10 of 137 questions
71. What are a virtual machines and site their advantages?
It is the concept by which an operating system can create an illusion that a process has its own processor with its own (virtual) memory. The operating system implements virtual machine concept by using CPU scheduling and virtual memory.
1. The basic advantage is it provides robust level of security as each virtual machine is isolated from all other VM. Hence the system resources are completely protected.
2. Another advantage is that system development can be done without disrupting normal o
72. What is a process?
A program in execution is called a process. Or it may also be called a unit of work. A process needs some system resources as CPU time, memory, files, and i/o devices to accomplish the task. Each process is represented in the operating system by a process control block or task control block (PCB).Processes are of two types:
1. Operating system processes
2. User processes
73. What are the states of a process?
1. New
2. Running
3. Waiting
4. Ready
5. Terminated
74. What are various scheduling queues?
1. Job queue
2. Ready queue
3. Device queue
75. What is a job queue?
When a process enters the system it is placed in the job queue.
76. What is a ready queue?
The processes that are residing in the main memory and are ready and waiting to execute are kept on a list called the ready queue.
77. What is a device queue?
A list of processes waiting for a particular I/O device is called device queue.
78. What is a long term scheduler & short term schedulers?
Long term schedulers are the job schedulers that select processes from the job queue and load them into memory for execution. The short term schedulers are the CPU schedulers that select a process form the ready queue and allocate the CPU to one of them.
79. What is context switching?
Transferring the control from one process to other process requires saving the state of the old process and loading the saved state for new process. This task is known as context switching.
80. What are the disadvantages of context switching?
Time taken for switching from one process to other is pure over head. Because the system does no useful work while switching. So one of the solutions is to go for threading when ever possible.