Introduction to Operating Systems


An operating system is a program that acts as an intermediary between a user and the computer hardware. Its purpose is to provide an environment in which a user can conveniently and efficiently run or execute programs.

Basics Of Operating System:

An operating system or OS is a set of system software programs in a computer that regulate the ways application software programs use the computer hardware and the ways that users control the computer.

The job of an operating system is to manage hardware and software resources of the system. Examples of hardware resources includes hard disk, memory, disk space, processor, mouse, keyboard, printers, other peripherals, etc. whereas software resources includes all kinds of system software’s like Windows, Linux, Unix, DOS, BIOS, Device Driver Software’s, Assembler and Compilers, etc. Application software cannot run on itself but is dependent on system software to execute. Examples of application software include MS Word, MS Excel, a console game, a library management system, a spreadsheet system etc.

“An operating system is a software that controls the internal activities of the computer hardware and provides user interface.”

Popular operating systems are Windows XP, Windows Vista, OS/2 and UNIX.

Operating System or OS is primarily concerned with allocating and deallocating computer resources to one or more jobs.

It can be looked as a cover, placed over the hardware. Thus, it is an important part of any computer system.

Operating systems can be classified into four categories:

a. Single User Operating System: Only one user can work at a time. e.g. DOS, Windows XP
b. Multiuser Operating System: Multiple users can work at the same time on a single computer. e.g. Linux, Unix, Windows 2000, etc.
c. Single tasking Operating System: OS that can execute only one job or program at a time. e.g. DOS
d. Multitasking Operating System: Its an operating system that supports execution of more than one job at a time. e.g. Windows 2000, UNIX, LINUX, OS/2, etc.

Functions of operating system:

  • Processor Management
  • Memory Management
  • Input/Output Management
  • File Management
  • Scheduling
  • Timesharing
  • Security Management

We will continue with operating system functions and Windows/Unix/Linux operating systems in coming posts.