NeXTSTEP

NeXTSTEP is a discontinued object-oriented, multitaskingoperating system developed by NeXT, the technology company founded by Steve Jobs. Based on the Mach kernel and the UNIX-derived BSD, it was introduced in 1989 for the company's computers before being ported to several other computer architectures. Following NeXT's transition away from hardware, version 4 was released as OPENSTEP for Mach, named after the company's OpenStep application programming interface (API).

Although relatively unsuccessful at the time, NeXTSTEP is notable for its influence on software development and computing history. Tim Berners-Lee developed the first web browser and web server on a NeXTSTEP workstation, while id Software used the operating system during development of Doom and Quake.

In 1996, Apple Computer acquired NeXT and used NeXTSTEP and OPENSTEP as the foundation for Mac OS X (later macOS). Its technologies continue to form the basis of Darwin, the core operating system underlying macOS, iOS, iPadOS, watchOS, and tvOS.