Editing OpenStep (section)

==Implementations==
{{Unsourced section|date=March 2023}}
=== OPENSTEP for Mach ===
NeXT's first operating system was [[NeXTSTEP]], a sophisticated Mach-UNIX based operating system that originally ran only on NeXT's [[Motorola 68000 family|Motorola 68k]]-based workstations and that was then ported to run on [[IA-32|32-bit Intel x86]]-based [[IBM PC compatible|"IBM-compatible" personal computers]], [[PA-RISC]]-based workstations from [[Hewlett-Packard]], and [[SPARC]]-based workstations from [[Sun Microsystems]].

NeXT completed an implementation of OpenStep on their existing Mach-based OS and called it '''OPENSTEP for Mach''' 4.0 (July, 1996), 4.1 (December, 1996), and 4.2 (January, 1997). It was, for all intents, NeXTSTEP 4.0, and still retained flagship NeXTSTEP technologies (such as [[Display PostScript|DPS]], UNIX underpinnings, user interface characteristics like the [[Dock (computing)|Dock]] and [[Shelf (computing)|Shelf]], and so on), and retained the classic NeXTSTEP user interface and styles. OPENSTEP for Mach was further improved, in comparison to NeXTSTEP 3.3, with vastly improved driver support &ndash; however the environment to actually write drivers was changed with the introduction of the object-oriented DriverKit.

OPENSTEP for Mach supported Intel x86-based PC's, Sun's SPARC workstations, and NeXT's own 68k-based architectures, while the HP PA-RISC version was dropped. These versions continued to run on the underlying Mach-based OS used in NeXTSTEP. OPENSTEP for Mach became NeXT's primary OS from 1995 on, and was used mainly on the Intel platform. In addition to being a complete OpenStep implementation, the system was delivered with a complete set of NeXTSTEP libraries for backward compatibility. This was an easy thing to do in OpenStep due to library versioning, and OPENSTEP did not suffer in bloat because of it.

===Solaris OpenStep===
In addition to the OPENSTEP for Mach port for SPARC, Sun and NeXT developed an OpenStep compliant set of frameworks to run on Sun's [[Solaris (operating system)|Solaris]] operating system. After developing Solaris OpenStep, Sun lost interest in OpenStep and shifted its attention toward Java. As a virtual machine development environment, Java served as a direct competitor to OpenStep. Unlike other versions, Solaris OpenStep had Interface Builder and Project Builder sold in a separate package called Workshop OpenStep.<ref>{{cite web |title=OpenStep Development Tools - 1 Introduction |url=http://docs.sun.com/app/docs/doc/802-2110/6i63kq4s7?a=view |website=docs.sun.com |access-date=21 May 2023 |archive-url=https://web.archive.org/web/20050427180415/http://docs.sun.com/app/docs/doc/802-2110/6i63kq4s7?a=view |archive-date=27 Apr 2005 |url-status=dead}}</ref><ref name="openstep-solaris-pr" />

===OPENSTEP Enterprise===
NeXT also delivered an implementation running on top of [[Windows NT 4.0]] called '''OPENSTEP Enterprise''' (often abbreviated OSE). This was an unintentional demonstration on the true nature of the portability of programs created under the OpenStep specification. Programs for OPENSTEP for Mach could be ported to OSE with little difficulty. This allowed their existing customer base to continue using their tools and applications, but running them on Windows, to which many of them were in the process of switching. Never a clean match from the UI perspective, probably due to OPENSTEP's routing of window graphics through the Display Postscript server&mdash;which was also ported to Windows&mdash;OSE nevertheless managed to work fairly well and extended OpenStep's commercial lifespan.

OPENSTEP and OSE had two revisions (and one major one that was never released) before NeXT was purchased by Apple in 1997.

===Rhapsody, Mac OS X Server 1.0===
{{Main|Rhapsody (operating system)|Mac OS X Server 1.0|Cocoa (API)}}
After acquiring NeXT, Apple intended to ship [[Rhapsody (operating system)|Rhapsody]] as a reworked version of OPENSTEP for Mach for both the Mac and standard PCs. Rhapsody was OPENSTEP for Mach with a [[Copland (operating system)|Copland]] appearance from [[Mac OS 8]] and support for Java and Apple's own technologies, including [[ColorSync]] and [[QuickTime]]; it could be regarded as OPENSTEP 5. Two developer versions of Rhapsody were released, known as Developer Preview 1 and 2; these ran on a limited subset of both Intel and PowerPC hardware.  [[Mac OS X Server 1.0]] was the first commercial release of this operating system, and was delivered exclusively for PowerPC Mac hardware.

===Darwin, Mac OS X 10.0 and later===
{{Main|Darwin (operating system)|macOS}}
After replacing the Display Postscript WindowServer with [[Quartz (graphics layer)|Quartz]], and responding to developers by including better backward compatibility for classic Mac OS applications through the addition of [[Carbon (API)|Carbon]], Apple released [[Mac OS X]] and [[Mac OS X Server]], starting at version 10.0; Mac OS X is now named macOS.

macOS's primary programming environment is essentially OpenStep (with certain additions such as XML property lists and URL classes for Internet connections) with macOS ports of the development libraries and tools, now called [[Cocoa (API)|Cocoa]].

macOS has since become the single most popular desktop Unix-like operating system in the world, although macOS is no longer an OpenStep compliant operating system.{{citation needed|date=May 2013}}

===GNUstep===
{{Main|GNUstep}}

GNUstep, a [[free software]] implementation of the [[NeXT]] libraries, began at the time of NeXTSTEP, predating OPENSTEP. While OPENSTEP and OSE were purchased by Apple, who effectively ended the commercial development of implementing OpenStep for other platforms, GNUstep is an ongoing open source project aiming to create a portable, free software implementation of the Cocoa/OPENSTEP libraries.

GNUstep also features a fully functional development environment, reimplementations of some of the newer innovations from macOS's [[Cocoa (API)|Cocoa]] framework, as well as its own extensions to the API.