Operating environment

In computer software, an operating environment or integrated applications environment is the environment in which users run application software. The environment consists of a user interface provided by an applications manager and usually an application programming interface (API) to the applications manager.

An operating environment is usually not a full operating system but is a form of middleware that rests between the OS and the application. For example, the first version of Microsoft Windows, Windows 1.0, was not a full operating system, but a GUI laid over DOS albeit with an API of its own. Similarly, the IBM U2 system operates on both Unix/Linux and Windows NT. Usually the user interface is text-based or graphical, rather than a command-line interface (e.g., DOS or the Unix shell), which is often the interface of the underlying operating system.

In the mid 1980s, text-based and graphical user interface operating environments such as IBM TopView, Microsoft Windows, Digital Research's GEM Desktop and Quarterdeck Office Systems's DESQview surrounded DOS operating systems with a shell that turned the user's display into a menu-oriented "desktop" for selecting and running PC applications. These programs were more than simple menu systems—as alternate operating environments they were substitutes for integrated programs such as Framework and Symphony, that allowed switching, windowing and cut-and-paste operations among dedicated applications. These operating environment systems gave users much of the convenience of integrated software without locking them into a single package. Alternative operating environments made TSR pop-up utilities such as Borland Sidekick redundant. Windows provided its own version of these utilities, and placing them under central control could eliminate memory conflicts that RAM-resident utilities create. In later versions, Windows evolved from an operating environment into a complete operating system.

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