What is Operating System (OS) ?

what is operating system

An operating system is the most critical software that works as an interface between computer hardware and the user. The chief objective of an operating system is the efficient utilisation of computer hardware. It also manages the memory and processes of a computer. It performs the basic tasks such as receiving input from the keyboard, processing the data received and giving output to the screen. In short, without an operating system, a computer is just a box, not a machine.

An operating system is a software which is necessary to run programs and applications. It is stored in the BIOS (basic input/output system), when a user starts the computer then BIOS reads all the instructions necessary for executing the operating system.

Read – Basic components of a computer system

The job of operating system

Operating system (OS) is the backbone of a computer, which manages all of the hardware and software on the computer. It also coordinates and manages the different programs running at a time, ensuring that each program gets to access central processing unit (CPU), memory, and storage when needed.

When you turn on a computer, the first software you see is an operating system. The operating system program is loaded into computer’s main memory when it is switched on. This program is known as the kernel. The kernel, bridge between the shell and hardware, and the shell, bridge between the user and the kernel, are the important parts of the OS that perform essential operations.

An OS perform these functions:

  1. Managing Computer Memory
  2. Process or Task management (single process and multitasking)
  3. Memory allocation of the data (storage management)
  4. Input/output management
  5. Kernel ( used for scheduling)

Types of Operating Systems:

In modern computer operating systems usually come pre-loaded, but it’s possible to change or upgrade them. Operating systems are commonly classified as:

  1. single-user OS (example: Windows 3x and MS-DOS) or multi-user OS (example: UNIX)
  2. single-tasking or multi-tasking (Real-time) OS (example: RTLinux)

Note: A multi-user OS must be multi-tasking like UNIX

Three most common operating systems for personal computers are:

  1. Microsoft Windows
  2. Mac OS X
  3. Linux

Modern operating systems use GUI (graphical user interface), which enables you to communicate with a computer through the use of symbols such as menus, icons, and buttons. With GUI everything is clearly displayed on the screen of the computer using a combination of text and graphics.

The GUI of every operating system has a different look and feel, but most of the basic principles are same in all.

Let’s know a bit more on the 3 most used Operating systems:

Microsoft Windows

Microsoft Windows is an operating system for computers made by American multinational technology company Microsoft Corp. The company created the Windows OS in the mid-1980s. Windows comes pre-loaded on most new computers, which makes it one of the most popular and most used operating system worldwide. Over the years, Microsoft released several versions of Windows, some of the recent ones are:

  1. Windows 10 (released in 2015)
  2. Windows 8 (released in 2012)
  3. Windows 7 (released in 2009)
  4. Windows Vista (released in 2007)

Mac OS X

Mac OS is a line of operating systems made by American multinational technology company Apple Inc. The OS comes pre-loaded on all new Macintosh computers (Macs). All of the recent versions of Mac OS are known as OS X (O-S Ten). Some of the recent specific versions of Mac OS X include:

  1. El Capitan (released in 2015)
  2. Yosemite (released in 2014)
  3. Mavericks (released in 2013)
  4. Mountain Lion (released in 2012)


Linux is the most-used open source operating system, which has been around since the mid-90s. Unlike Windows or Mac OS, which can only be modified by the company that owns it, Linux can be modified and distributed by anyone across the globe.

Being open-source, Linux has some advantages the first is that it is freely available and the second is that there are several versions to choose from. Some of the recent versions of Linux include:

  1. Linux Mint
  2. Arch Linux
  3. Ubuntu
  4. Tails

Today we have different types of OS that act as a middleware between the user and the computer hardware, thus providing easy interactions. To learn more about computers, click http://www.opennaukri.com/basic-components-of-a-computer-system/

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