OS Unit 2 : Concurrent Processes Previous Year Questions

On this page, you will find all the most important and most asked questions from unit 2 of the Operating System subject. 

Topic : Intro to DST (Key Note and Questions)

Key Note:

  • Data Structure is a way to organize data so that we can perform any operation on it efficiently.
  • Data type describes which type of value a variable can store. Means if a variable is of int data type it means that, that particular variable can store only integer data.
  • Built-in data type is also known as predefined data type which can be directly used by any programmer to a variable types and assign value in it.
  • Some example of built-in data type are int, char, float, double, short, long etc.


  1. What is process and process model?
  2. Explain the various states of process.
  3. What do you understand by context switching? Explain with the help of diagram.

Topic : Algorithm (Key Note and Questions)

Key Note:

  • Algorithm can be defined as a step by step approach  to solve a problem in finite steps and time. It is a human-readable solution.
  • Efficiency of an Algorithm shows the quality of algorithm. Here the parameter for quality is algorithm should take less time and space to solve any problem. 
  • Time complexity shows time taken by an algorithm to solve a problem.
  • Space complexity show space/memory taken by an algorithm to solve a problem.
  1. What do you understand by process control block? Write the various type of information contain by PCB.
  2. Write the difference between long term, middles term and short term schedulers.
  3. What is Interprocess communication? Discuss its two models.
  4. What is thread? Write the difference between user level and kernel level thread. write its advantage and disadvantage.

Key Note:

  • Asymptotic notation helps to measure the complexity of an algorithm. It is of 5 types Big-Oh, Omega, Theta, Little Oh and Little Omega.
  • An Abstract datatype is a datatype, whose behavior is defined by a set of values and set of operations. for example stack and queue is a perfect example of ADT.
  1. What is the goal of CPU scheduling algorithm?
  2. Describe dispatcher.
  3. What is concurrency? Write its principle.
  4. What do you understand by critical section. Explain.
  5. What are the requirements of critical section problem.
  6. What is race condition? Explain with the help of producer and consumer problem.
  7. What is mutual exclusion. Write its four condition and explain it.
  8. Write and explain the Peterson solution to the critical section problem.
  9. What is semaphore? Explain.
  10. Discuss the classical problem of synchronization.
  11. Write an algorithm for producer-consumer problem.
  12. Describe the reader-writer problem.
  13. Describe the Dining-philosopher problem.
  14. Write the sleeping barber problem of synchronization.