What is main purpose of operating system? Discuss different types


  • An operating system is a user interface i.e. a program that acts as an interface between the user and the computer hardware.
  • It is a program that controls the execution of application programs 
  • It is an interface between application and hardware
  • Different types of operating systems are Single-tasking, Multiprogramming, Multitasking, Multithreading, Multiprocessing, and Multiuser. 


The article explains the main purpose of an operating system and also discusses its different types.


An operating system acts as an intermediary between the user of a computer and the computer hardware.

There are three different reasons why an operating system is used:

  1. Abstraction: There is no need to write assembly or binary code for basic hardware operations.
  2. Resource Management: Based on the priorities of the processes, the operating system decides which process should be loaded to RAM to run. 
  3. Protection: the operating system ensures that one application does not impact the other. 

Based on the functionality operating system is classified as

  1. Single-tasking: In a single-tasking system only one process other than the operating system can exist in RAM at a time. Example MS-DOS.
  2. Multiprogramming and multitasking: In multiprogramming, multiple processes are run concurrently using a single CPU. Multitasking is an extension of multiprogramming. In multitasking, a specific time slot is given to each process to run. This increases responsiveness. 
  3. Multithreading: In multithreading, multiple threads run within a process in an interleaved fashion. A thread is the smallest unit of CPU utilization. Multiple threading increases the responsiveness and CPU utilization. In multithreading switching from one thread to another within the process is less costly as compared to switching between the processes. 
  4. Multiprocessing: Multiprocessing is an operating system that supports multiple processors. It makes the computer run faster because all the programs are distributed to various processors.
  5. Multi-User: A multiuser operating system allows multiple users to access a single system with one operating system on it 


  • An operating system is an interface between the user and the computer hardware. 
  • The three different reasons why we use operating systems are abstraction, resource management, and protection.
  • The operating system is classified as Single-tasking, Multiprogramming, Multitasking, Multithreading, Multiprocessing, and Multiuser.

Special thanks to Avaneet Kaur Saluja for contributing to this article on takeUforward. If you also wish to share your knowledge with the takeUforward fam, please check out this article