Editing Plan 9 from Bell Labs (section)

== History ==
[[File:Plan 9 Fourth Edition installing file system screenshot.png|thumb|Screenshot of Plan 9 installation]]
Plan 9 from Bell Labs was originally developed, starting in the late 1980s,<ref name="9atom-home" /> by members of the Computing Science Research Center at Bell Labs, the same group that originally developed [[Unix]] and the [[C (programming language)|C programming language]].<ref name="creators" /> The Plan 9 team was initially led by [[Rob Pike]], [[Ken Thompson (computer programmer)|Ken Thompson]], Dave Presotto and Phil Winterbottom, with support from [[Dennis Ritchie]] as head of the Computing Techniques Research Department.  Over the years, many notable developers have contributed to the project, including [[Brian Kernighan]], [[Tom Duff]], [[Doug McIlroy]], [[Bjarne Stroustrup]] and Bruce Ellis.<ref name="developers" />

Plan 9 replaced Unix as Bell Labs's primary platform for operating systems research.<ref>{{Cite web |last=Proven |first=Liam |date=2022-03-29 |title=The weird world of non-C operating systems |url=https://www.theregister.com/2022/03/29/non_c_operating_systems/ |access-date=2022-09-01 |website=www.theregister.com |language=en}}</ref> It explored several changes to the original Unix model that facilitate the use and programming of the system, notably in distributed [[multi-user]] environments. After several years of development and internal use, Bell Labs shipped the operating system to universities in 1992. Three years later, Plan 9 was made available for commercial parties by AT&T via the book publisher [[Harcourt Brace]]. With source licenses costing $350, AT&T targeted the embedded systems market rather than the computer market at large. Ritchie commented that the developers did not expect to do "much displacement" given how established other operating systems had become.<ref>{{cite news |newspaper=[[InfoWorld]] |first=Yvonne L. |last=Lee |title=AT&T Bell Labs ships Plan 9 OS for embedded systems |url=https://books.google.com/books?id=3joEAAAAMBAJ&pg=PA16 |date=24 July 1995}}</ref>

By early 1996, the Plan 9 project had been "put on the back burner" by AT&T in favor of [[Inferno (operating system)|Inferno]], intended to be a rival to [[Sun Microsystems]]' [[Java (software platform)|Java platform]].<ref>{{cite news |title=AT&T reveals plans for Java competitor |url=https://books.google.com/books?id=xT4EAAAAMBAJ&pg=PA3 |newspaper=InfoWorld |first=Jason |last=Pontin |date=19 February 1996 |page=3}}</ref>
In the late 1990s, Bell Labs' new owner [[Lucent Technologies]] dropped commercial support for the project and in 2000, a third release was distributed under an [[open-source license]].<ref name=":0">{{Cite web |last= |first= |date=2021-11-14 |title=Bell Labs: A Complete Guide — History, Products, Founding, and More |url=https://history-computer.com/bell-labs-history/ |access-date=2022-09-01 |website=History-Computer |language=en-US}}</ref> A fourth release under a new [[free software]] license occurred in 2002.<ref name="osnews-4th-edition-release" /> In early 2015, the final official release of Plan 9 occurred.<ref name=":0" />

A user and development community, including current and former [[Bell Labs]] personnel, produced minor daily releases in the form of [[ISO image]]s. Bell Labs hosted the development.<ref name="how-to-contribute" /> The development source tree is accessible over the [[9P (protocol)|9P]] and [[Hypertext Transfer Protocol|HTTP]] protocols and is used to update existing installations.<ref name= "staying-up-to-date" /> In addition to the official components of the OS included in the ISOs, Bell Labs also hosts a repository of externally developed applications and tools.<ref>{{cite web|url=https://9p.io/plan9/addons.html|title=Plan 9 — Additional Software|date=2009|access-date=2016-03-06}}</ref>

As [[Bell Labs]] has moved on to later projects in recent years, development of the official Plan 9 system had stopped. On March 23, 2021, development resumed following the transfer of copyright from [[Bell Labs]] to the Plan 9 Foundation.<ref name="plan9 copyright transfer">{{cite web |last1=Sorace |first1=Anthony |title=Transfer of Plan 9 to the Plan 9 Foundation |url=https://marc.info/?l=9fans&m=161650489113326|website=marc.info |access-date=2020-04-14 |archive-date=13 April 2021 |archive-url=https://web.archive.org/web/20210413225220/https://marc.info/?l=9fans&m=161650489113326}}</ref><ref>{{cite web |last1=Weldon |first1=Marcus |title=Plan 9 from Bell Labs in Cyberspace! |url=https://www.bell-labs.com/institute/blog/plan-9-bell-labs-cyberspace/ |website=Nokia Bell Labs |date=23 March 2021 |access-date=23 March 2021}}</ref><ref>{{Cite web|last=Sharwood|first=Simon|title=Bell Labs transfers copyright of influential 'Plan 9' OS to new foundation|url=https://www.theregister.com/2021/03/24/bell_labs_transfers_plan9pto_foundation/|access-date=2021-03-24|website=[[The Register]]|language=en}}</ref> Unofficial development for the system also continues on the 9front fork, where active contributors provide monthly builds and new functionality. So far, the 9front fork has provided the system [[Wi-Fi]] drivers, Audio drivers, [[USB]] support and built-in game emulator, along with other features.<ref>{{Cite web|url=http://fqa.9front.org/fqa1.html|title=FQA 1 - Introduction To 9front|website=fqa.9front.org|access-date=2018-02-15}}</ref><ref>{{Cite web |last=Proven |first=Liam |title=New version of Plan 9 fork 9front released |url=https://www.theregister.com/2022/11/02/plan_9_fork_9front/ |access-date=2022-11-05 |website=[[The Register]] |language=en}}</ref> Other recent Plan 9-inspired operating systems include Harvey OS<ref>{{Cite web|url=https://harvey-os.org/about/|title=Harvey OS|website=harvey-os.org|language=en|access-date=2018-02-15}}</ref> and Jehanne OS.<ref>{{Cite web|url=http://jehanne.h--k.it/pages/overview.html|title=Jehanne|website=jehanne.h--k.it/|access-date=2023-01-08}}</ref>

{| class="wikitable"
|-
! Date
! Release
! Comment
|-
| 1992
| Plan 9 1st edition
| Released by Bell Labs to universities
|-
| 1995
| Plan 9 2nd edition
| Released by Bell Labs for non-commercial purposes<ref name="firstpublic" />
|-
| 2000
| Plan 9 3rd ed. (''Brazil'')
| Released by Lucent Technologies under an open source license
|-
| 2002
| Plan 9 4th edition
| Released by Lucent Technologies under a new free software license
|}