Editing History of operating systems (section)

==Minicomputers==
Digital Equipment Corporation created several operating systems for its 16-bit [[PDP-11]] machines, including the simple [[RT-11]] system, the time-sharing [[RSTS/E|RSTS]] operating systems, and the [[RSX-11]] family of [[real-time operating system]]s, as well as the [[OpenVMS|VMS]] system for the 32-bit [[VAX]] machines.

Several competitors of Digital Equipment Corporation such as [[Data General]], [[Hewlett-Packard]], and [[Computer Automation]] created their own operating systems. One such, "MAX III", was developed for [[MODCOMP|Modular Computer Systems]] Modcomp II and Modcomp III computers. It was characterised by its target market being the industrial control market. The Fortran libraries included one that enabled access to measurement and control devices.

IBM's key innovation in operating systems in this class (which they call "mid-range"), was their "CPF" for the [[IBM System/38|System/38]]. This had [[capability-based addressing]], used a machine interface architecture to isolate the application software and most of the operating system from hardware dependencies (including even such details as address size and register size) and included an integrated [[Relational database management system|RDBMS]]. The succeeding OS/400 (now known as [[IBM i]]) for the [[IBM AS/400]] and later [[IBM Power Systems]] has no files, only objects of different types and these objects persist in very large, flat virtual memory, called a single-level store.

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The [[Unix]] operating system was developed at AT&T Bell Laboratories in the late 1960s, originally for the [[PDP-7]], and later for the PDP-11. Because it was essentially free in early editions, easily obtainable, and easily modified, it achieved wide acceptance. It also became a requirement within the Bell systems operating companies. Since it was written in the [[C (programming language)|C language]], when that language was ported to a new machine architecture, Unix was also able to be ported. This portability permitted it to become the choice for a second generation of minicomputers and the first generation of [[workstation]]s, and its use became widespread. Unix exemplified the idea of an operating system that was conceptually the same across various hardware platforms. Because of its utility, it inspired many and later became one of the roots of the [[free software]] movement and [[open-source software]]. Numerous operating systems were based upon it including [[Minix]], [[History of Linux|GNU/Linux]], and the [[Berkeley Software Distribution]]. Apple's [[macOS]] is also based on Unix via [[NeXTSTEP]]<ref>{{cite news |url=https://arstechnica.com/apple/2012/12/the-legacy-of-next-lives-on-in-os-x/ |title=The legacy of NeXT lives on in OS X |author=Chris Foresman |date=19 December 2012}}</ref> and [[FreeBSD]].<ref>{{cite magazine |url=https://www.wired.com/2013/08/jordan-hubbard/ |title=Apple's Operating System Guru Goes Back to His Roots |author=Klint Finley |date=8 August 2013 |magazine=[[Wired (magazine)|Wired]]}}</ref>

The [[Pick operating system]] was another operating system available on a wide variety of hardware brands. Commercially released in 1973 its core was a [[BASIC]]-like language called Data/BASIC and a SQL-style database manipulation language called ENGLISH. Licensed to a large variety of manufacturers and vendors, by the early 1980s observers saw the Pick operating system as a strong competitor to Unix.<ref name="fiedler198310">{{cite news | url=https://archive.org/stream/byte-magazine-1983-10/1983_10_BYTE_08-10_UNIX#page/n133/mode/2up | title=The Unix Tutorial / Part 3: Unix in the Microcomputer Marketplace | work=BYTE | date=October 1983 | access-date=30 January 2015 | author=Fiedler, Ryan | pages=132}}</ref>