What is an operating system?
An operating system is the most important software that runs on a computer. It manages the computer's memory, processes, and all of its software and hardware. It also allows you to communicate with the computer without knowing how to speak the computer's "language." Without an operating system, a computer is useless.
Watch the video to learn about operating systems.
The operating system's job
Your computer's operating system (OS) manages all of the software and hardware on the computer. Most of the time, there are many different computer programs running at the same time, and they all need to access your computer's central processing unit (CPU), memory, and storage. The operating system coordinates all of this to make sure each program gets what it needs.
Types of operating systems
Operating systems usually come preloaded on any computer that you buy. Most people use the operating system that comes with their computer, but it is possible to upgrade or even change operating systems.
The three most common operating systems for personal computers are Microsoft Windows, Apple Mac OS X, and Linux.
Modern operating systems use a Graphical User Interface, or GUI (pronounced "gooey"). A GUI lets you use your mouse to click on icons, buttons, and menus, and everything is clearly displayed on the screen using a combination of graphics and text.
Each operating system's GUI has a different look and feel, so if you switch to a different operating system it may seem unfamiliar at first. However, modern operating systems are designed to be easy to use, and most of the basic principles are the same.
Before GUIs, computers had a command-line interface, which meant the user had to type every single command to the computer, and the computer would only display text.