Operating system

An operating system (OS) is software that manages computer resources and provides programmers/users with an interface used to access those resources. An operating system processes system data and user input, and responds by allocating and managing tasks and internal system resources as a service to users and programs of the system. An operating system performs basic tasks such as controlling and allocating memory, prioritizing system requests, controlling input and output devices, facilitating computer networking and managing files. Operating systems can be found on almost anything made with integrated circuits, such as personal computers, internet servers, cellphones, music players, routers, switches, wireless access points, network storage, game consoles, digital cameras, sewing machines and telescopes.

In most cases, the operating system is not the first code to run on the computer at startup (boot) time. The initial code executing on the computer is usually loaded from firmware, which is stored in Flash ROM. This is sometimes called the BIOS or boot ROM. The firmware loads and executes the operating system kernel (usually from disk, sometimes over the network), and is usually responsible for the first graphics or text output the user sees on screen.

Common contemporary operating systems include Linux, Mac OS X, Microsoft Windows and Solaris. Microsoft Windows is has a significant majority of market share in the desktop and notebook computer markets, while the server and embedded device markets are split amongst several operating systems. With the exception of Microsoft Windows, the designs of each of the aforementioned operating systems were inspired by, or directly inherited from, the Unix operating system. Unix was developed at Bell Labs beginning in the late 1960s and spawned the development of numerous free and proprietary operating systems.