Editing MacOS version history (section)

===Development outside Apple===
[[File:Unix history-simple.svg|thumb|400px|A diagram of the relationships between Unix systems including the ancestors of macOS]]
After [[Apple Inc.|Apple]] removed [[Steve Jobs]] from management in 1985, he left the company and attempted to create the "next big thing", with funding from [[Ross Perot]]<ref>{{cite book|last=Isaacson|first=Walter|author-link=Walter Isaacson|year=2011|title=Steve Jobs|url=https://archive.org/details/stevejobs00isaa|url-access=registration|page=[https://archive.org/details/stevejobs00isaa/page/227 227]|publisher=[[Simon & Schuster]]|isbn=978-1-4087-0374-8}}</ref> and himself. The result was the [[NeXT Computer]]. As the first workstation to include a [[digital signal processor]] (DSP) and a high-capacity optical disc drive, NeXT hardware was advanced for its time, but was expensive relative to the rapidly commoditizing workstation market. The hardware was phased out in 1993; however, the company's [[object-oriented operating system]] [[NeXTSTEP]] had a more lasting legacy as it eventually became the basis for Mac OS X.

NeXTSTEP was based on the [[Mach kernel]] developed at CMU (Carnegie Mellon University)<ref>A Practical Guide to Linux Commands, Editors, and Shell Programming, 3rd edition, by Mark G. Sobell, page 2</ref> and [[Berkeley Software Distribution|BSD]], an implementation of [[Unix]] dating back to the 1970s. It featured an [[object-oriented]] programming [[Software framework|framework]] based on the [[Objective-C]] language. This environment is known today in the Mac world as [[Cocoa (API)|Cocoa]]. It also supported the innovative [[Enterprise Objects Framework]] database access layer and [[WebObjects]] application server development environment, among other notable features.{{Citation needed|date=February 2021}}

All but abandoning the idea of an operating system, NeXT managed to maintain a business selling WebObjects and consulting services, only ever making modest profits in its last few quarters as an independent company. NeXTSTEP underwent an evolution into [[OPENSTEP]] which separated the object layers from the operating system below, allowing it to run with less modification on other platforms. OPENSTEP was, for a short time, adopted by [[Sun Microsystems|Sun]] and [[Hewlett-Packard|HP]].

However, by this point, a number of other companies — notably Apple, IBM, Microsoft, and even Sun itself — were claiming they would soon be releasing similar object-oriented operating systems and development tools of their own. Some of these efforts, such as [[Taligent]], did not fully come to fruition; others, like [[Java platform|Java]], gained widespread adoption.{{Citation needed|date=February 2021}}

On February 4, 1997, [[Apple Inc.|Apple Computer]] acquired NeXT for $427 million, and used OPENSTEP as the basis for [[Mac OS X]], as it was called at the time.<ref>{{cite book | title=Apple Confidential: The Real Story of Apple Computer, Inc | url=https://archive.org/details/appleconfidentia00linz | url-access=registration | last=Linzmayer | first=Owen W. | year=1999| publisher=No Starch Press | isbn=9781886411289 }}</ref> Traces of the NeXT software heritage can still be seen in macOS. For example, in the [[Cocoa (API)|Cocoa]] development environment, the [[Objective-C]] library classes have "NS" prefixes, and the HISTORY section of the manual page for the <code>defaults</code> command in macOS straightforwardly states that the command "First appeared in NeXTStep."{{Citation needed|date=February 2021}}