Editing Operating system (section)

==History==
{{Main|History of operating systems}}
[[File:IBM system 360-50 console - MfK Bern.jpg|thumb|IBM System/360 Model 50 operator's console and CPU; the operator's console is a [[computer terminal|terminal]] used by the operating system to communicate with the operator.]]

The first computers in the late 1940s and 1950s were directly programmed either with [[plugboard]]s or with [[machine code]] inputted on media such as [[punch card]]s, without [[programming language]]s or operating systems.{{sfn|Tanenbaum|Bos|2023|p=8}} After the introduction of the [[transistor]] in the mid-1950s, [[mainframe]]s began to be built. These still needed professional operators{{sfn|Tanenbaum|Bos|2023|p=8}} who manually do what a modern operating system would do, such as scheduling programs to run,<ref name="OSTEP book">{{cite book |last1=Arpaci-Dusseau |first1=Remzi |last2=Arpaci-Dusseau |first2=Andrea |year=2015 |url=http://pages.cs.wisc.edu/~remzi/OSTEP/ |title=Operating Systems: Three Easy Pieces |access-date=25 July 2016 |archive-date=25 July 2016 |archive-url=https://web.archive.org/web/20160725012948/http://pages.cs.wisc.edu/~remzi/OSTEP/ |url-status=live }}</ref> but mainframes still had rudimentary operating systems such as [[Fortran Monitor System]] (FMS) and [[IBSYS]].{{sfn|Tanenbaum|Bos|2023|p=10}} In the 1960s, [[IBM]] introduced the first series of intercompatible computers ([[System/360]]). All of them ran the same operating system—[[OS/360]]—which consisted of millions of lines of [[assembly language]] that had thousands of [[Software bug|bug]]s. The OS/360 also was the first popular operating system to support [[multiprogramming]], such that the CPU could be put to use on one job while another was waiting on [[input/output]] (I/O). Holding multiple jobs in [[memory (computing)|memory]] necessitated memory partitioning and safeguards against one job accessing the memory allocated to a different one.{{sfn|Tanenbaum|Bos|2023|pp=11–12}}

Around the same time, [[teleprinter]]s began to be used as [[computer terminal|terminal]]s so multiple users could access the computer simultaneously. The operating system [[MULTICS]] was intended to allow hundreds of users to access a large computer. Despite its limited adoption, it can be considered the precursor to [[cloud computing]]. The [[UNIX]] operating system originated as a development of MULTICS for a single user.{{sfn|Tanenbaum|Bos|2023|pp=13–14}} Because UNIX's [[source code]] was available, it became the basis of other, incompatible operating systems, of which the most successful were [[AT&T]]'s [[System V]] and the [[University of California]]'s [[Berkeley Software Distribution]] (BSD).{{sfn|Tanenbaum|Bos|2023|pp=14–15}} To increase compatibility, the [[IEEE]] released the [[POSIX]] standard for operating system [[application programming interface]]s (APIs), which is supported by most UNIX systems. [[MINIX]] was a stripped-down version of UNIX, developed in 1987 for educational uses, that inspired the commercially available, [[free software]] [[Linux]]. Since 2008, MINIX is used in controllers of most [[Intel]] [[microchips]], while Linux is widespread in [[data center]]s and [[Android (operating system)|Android]] smartphones.{{sfn|Tanenbaum|Bos|2023|p=15}}

===Microcomputers===
[[File:MS-Dos screenshot.png|thumb|[[Command-line interface]] of the [[MS-DOS]] operating system]]
[[File:System 1 File Edit.png|thumb|[[Graphical user interface]] of a [[Macintosh]]]]
The invention of [[large scale integration]] enabled the production of [[personal computer]]s (initially called [[microcomputer]]s) from around 1980.{{sfn|Tanenbaum|Bos|2023|pp=15–16}} For around five years, the [[CP/M]] (Control Program for Microcomputers) was the most popular operating system for microcomputers.{{sfn|Tanenbaum|Bos|2023|p=16}} Later, IBM bought the [[DOS]] (Disk Operating System) from [[Microsoft]]. After modifications requested by IBM, the resulting system was called [[MS-DOS]] ({{not a typo|Micro|Soft}} Disk Operating System) and was widely used on IBM microcomputers. Later versions increased their sophistication, in part by borrowing features from UNIX.{{sfn|Tanenbaum|Bos|2023|p=16}}

[[Apple Inc.|Apple]]'s [[Macintosh]] was the first popular computer to use a [[graphical user interface]] (GUI). The GUI proved much more [[user friendly]] than the text-only [[command-line interface]] earlier operating systems had used. Following the success of Macintosh, MS-DOS was updated with a GUI overlay called [[Windows]]. Windows later was rewritten as a stand-alone operating system, borrowing so many features from another ([[VAX VMS]]) that a large [[legal settlement]] was paid.{{sfn|Tanenbaum|Bos|2023|p=17}} In the twenty-first century, Windows continues to be popular on personal computers but has less [[market share]] of servers. UNIX operating systems, especially Linux, are the most popular on [[enterprise system]]s and servers but are also used on [[mobile device]]s and many other computer systems.{{sfn|Tanenbaum|Bos|2023|p=18}}

On mobile devices, [[Symbian OS]] was dominant at first, being usurped by [[BlackBerry OS]] (introduced 2002) and [[iOS]] for [[iPhone]]s (from 2007). Later on, the open-source [[Android (operating system)|Android]] operating system (introduced 2008), with a Linux kernel and a C library ([[Bionic (software)|Bionic]]) partially based on BSD code, became most popular.{{sfn|Tanenbaum|Bos|2023|pp=19–20}}