Principles of Operating Systems (applicable to BSC_IT/BCA/DCA)

Operating System and its Functions

An Operating System can be defined as an interface between user and hardware. It is responsible for the execution of all the processes, Resource Allocation, CPU management, File Management and many other tasks.

In the Computer System (comprises of Hardware and software), Hardware can only understand machine code (in the form of 0 and 1) which doesn't make any sense to a naive user.

We need a system which can act as an intermediary and manage all the processes and resources present in the system.


Here, comes the role of Operating System, which performs all the basic tasks like file management, memory management, process management, handling input and output, and controlling peripheral devices such as disk drives and printers. The purpose of an operating system is to provide an environment in which a user can execute programs in convenient and efficient manner

Examples of some popular Operating Systems are: Linux Operating System, Windows Operating System, VMS, OS/400, AIX, z/OS, etc.

Structure of a Computer System

A Computer System consists of:

Users (people who are using the computer)

  • Application Programs (Compilers, Databases, Games, Video player, Browsers, etc.)
  • System Programs (Shells, Editors, Compilers, etc.)
  • Operating System ( A special program which acts as an interface between user and hardware )
  • Hardware ( CPU, Disks, Memory, etc)

What does an Operating system do?

  1. Process Management
  2. Process Synchronization
  3. Memory Management
  4. CPU Scheduling
  5. File Management
  6. Security
  7. Job Accounting
  8. Device Management


    Check the video for functioning of Operating System:





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