What is an operating system?

In computing, an operating system (OS) is system software that manages computer hardware and software resources and provides common services for computer programs.

Operating systems are found on many devices that contain a computer such as personal computers, servers, smartphones, and tablet computers. Examples of popular desktop operating systems include Microsoft Windows, macOS, and Linux. Mobile operating systems include Android, iOS, and Windows 10 Mobile.

The defining feature of an operating system is that it provides a platform on which applications can run. Applications are programs that allow users to perform specific tasks on their devices. For example, a web browser allows users to browse the internet, while a word processor allows users to create documents.

Most modern operating systems provide multitasking, allowing one device to behave as multiple virtual devices. For example, a laptop can be seen by users as four virtual machines: one for each of its logical CPUs and physical RAM. System calls such as inter-process communication let applications synchronize with other parts of the operating system.

Operating systems are typically found on embedded devices such as video game consoles and personal digital assistants (PDAs). In contrast to these systems, servers perform tasks that are more traditional in a desktop environment, acting as the central point for all interactions between client computers and any specialised computer hardware connected to a network.