An operating system is a set of basic software that allows computers to perform basic tasks for people. It is responsible for displaying the graphics on screen and outputting sound to the speakers, controlling input from the mouse and keyboard, allowing hardware to work properly, interfacing with other computers on a network, and storing and retrieving data. The most common operating systems today are Microsoft Windows, Apple's OS X, and Linux/BSD.
An operating system is defined into a few basic parts:
- The BIOS, which handles all hardware related things. Often a computer has a BIOS integrated within its hardware, though some operating systems such as Linux are independent of this BIOS.
- The Kernel, which handles all software related things and acts as a interpreter between applications and the hardware.
- The shell or User Interface - Software that draws forms, toolbars, menus, main task bar, typing commands for the computer to execute, etc.