NeXTSTEP is a discontinued object-oriented, multitasking operating system based on the Mach kernel and the UNIX-derived BSD. It was developed by NeXT Computer in the late 1980s and early 1990s and was initially used for its range of proprietary workstation computers such as the NeXTcube. It was later ported to several other computer architectures. Although relatively unsuccessful at the time, it attracted interest from computer scientists and researchers. It hosted the original development of the Electronic AppWrapper, the first commercial electronic software distribution catalog to collectively manage encryption and provide digital rights for application software and digital media, a forerunner of the modern "app store" concept. It is the platform on which Tim Berners-Lee created the first web browser, and on which id Software developed the video games Doom and Quake. In 1996, NeXT was acquired by Apple Computer to succeed the classic Mac OS, by merging NeXTSTEP and OpenStep with Apple's user environment to become Mac OS X, renamed macOS. This powers all of Apple's platforms, including iOS. Overview NeXTSTEP (also stylized as NeXTstep, NeXTStep, and NEXTSTEP) is a combination of several parts: a Unix operating system based on the Mach kernel, plus BSD Display PostScript and a proprietary windowing engine the Objective-C language and runtime an object-oriented (OO) application layer, including several "kits" development tools for the OO layers. NeXTSTEP is a preeminent implementation of the last three items. The toolkits are the canonical development system for all of the software on the system. It introduced the idea of the Dock (carried through OpenStep and into macOS) and the Shelf. NeXTSTEP originated or innovated a large number of other GUI concepts which became common in other operating systems: 3D chiseled widgets, large full-color icons, system-wide drag and drop of a wide range of objects beyond file icons, system-wide piped services, real-time scrolling and window dragging, properties dialog boxes called "inspectors", and window modification notices (such as the saved status of a file). The system is among the first general-purpose user interfaces to handle publishing color standards, transparency, sophisticated sound and music processing (through a Motorola 56000 DSP), advanced graphics primitives, internationalization, and modern typography, in a consistent manner across all applications. Additional kits were added to the product line. These include Portable Distributed Objects (PDO), which allow easy remote invocation, and Enterprise Objects Framework, an object-relational database system. The kits made the system particularly interesting to custom application