# Research Unix

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Original Unix operating system from Bell Labs

**Research Unix** refers to the early versions of the [Unix](/source/Unix) operating system for [DEC PDP-7](/source/PDP-7), [PDP-11](/source/PDP-11), [VAX](/source/VAX), and [Interdata 7/32 and 8/32](/source/Interdata_7%2F32_and_8%2F32) computers, developed in the [Bell Labs](/source/Bell_Labs) Computing Sciences Research Center (CSRC). The term *Research Unix* first appeared in the [Bell System Technical Journal](/source/Bell_System_Technical_Journal) (Vol. 57, No. 6, Part 2 July/August 1978) to distinguish it from other versions internal to Bell Labs (such as [PWB/UNIX](/source/PWB%2FUNIX) and [MERT](/source/Multi-Environment_Real-Time)) whose code-base had diverged from the primary CSRC version. However, that term was little-used until Version 8 Unix (1985), but has been [retroactively](/source/Retroactive_continuity) applied to earlier versions as well. Prior to V8, the operating system was most commonly called simply UNIX (in caps) or the UNIX Time-Sharing System.

**Ancient UNIX** is any early release of the [Unix](/source/Unix) code base prior to Unix [System III](/source/System_III), particularly the Research Unix releases prior to and including Version 7 (the base for [UNIX/32V](/source/UNIX%2F32V) as well as later developments of [AT&T Unix](/source/AT%26T_Unix)).

## History

[AT&T](/source/AT%26T) licensed Version 5 to educational institutions, and Version 6 also to commercial sites. Schools paid $200 and others $20,000, discouraging most commercial use, but Version 6 was the most widely used version into the 1980s. Research Unix versions are often referred to by the edition of the [manual](/source/Man_page) that describes them,[1] because early versions and the last few were never officially released outside of Bell Labs, and grew organically. So, the first Research Unix would be the First Edition, and the last the Tenth Edition. Another common way of referring to them is as "Version *x* Unix" or "V*x* Unix", where *x* is the manual edition. All modern editions of Unix—excepting [Unix-like](/source/Unix-like) implementations such as [Coherent](/source/Coherent_(operating_system)), [Minix](/source/Minix), and [Linux](/source/Linux)—derive from the 7th Edition.[2]

Starting with the 8th Edition, versions of Research Unix had a close relationship to [BSD](/source/Berkeley_Software_Distribution). This began by using 4.1cBSD as the basis for the 8th Edition. In a [Usenet](/source/Usenet) post from 2000, [Dennis Ritchie](/source/Dennis_Ritchie) described these later versions of Research Unix as being closer to BSD than they were to [UNIX System V](/source/UNIX_System_V),[3] which also included some BSD code:[1]

Research Unix 8th Edition started from (I think) BSD 4.1c, but with enormous amounts scooped out and replaced by our own stuff. This continued with 9th and 10th. The ordinary user command-set was, I guess, a bit more BSD-flavored than SysVish, but it was pretty eclectic.

## Versions

Manual Edition Release date Description 1st Edition Nov 3, 1971 First edition of the Unix manual, based on the version that ran on the PDP-11 at the time. The operating system was two years old,[4] having been ported from the PDP-7 to the PDP-11/20 in 1970. Includes ar, as, bcd, cal, cat, chdir, chmod, chown, cmp, cp, date, dc, df, du, ed, glob, init, ld, ln, ls, mail, mesg, mkdir, mkfs, mount, mv, nm, od, pr, rm, rmdir, roff, sh, sort, stat, strip, su, sum, tty, umount, wc, who, write; also precursors of fsck, reboot, and adb. The system also had a B and Fortran compiler, a BASIC interpreter, device files and functions for managing punched tape, DECtape, and RK05 disks. 2nd Edition Jun 12, 1972 Total number of installations at the time was 10, "with more expected", according to the preface of the manual.[5]: ii Adds echo, exit, login, m6 macro processor, man, nroff, strip, stty, tmg compiler-compiler and the first C compiler.[4][5] 3rd Edition Feb 1973 Introduced a C debugger, pipes, crypt, kill, passwd, size, speak, split, uniq, and yacc. Commands are split between /bin and /usr/bin, requiring a search path[4] (/usr was the mount point for a second hard disk). Total number of installations was 16. 4th Edition Nov 1973 First version written in C. Also introduced comm, dump, file, grep, nice, nohup, ps, sleep, sync, tr, wait, and printf(3).[4] Included a SNOBOL interpreter. Number of installations was listed as "above 20". The manual was formatted with troff for the first time. Version described in Thompson and Ritchie's CACM paper,[6] the first public exposition of the operating system.[4] 5th Edition Jun 1974 Version 5 Unix for the PDP-11, running on SIMH Licensed to selected educational institutions.[1] Introduced col, dd, diff, eqn, find, lpr, pwd, spell, tee, [4] and the sticky bit. Targeted the PDP-11/40 and other 11 models with 18 bit addresses. Installations "above 50". 6th Edition May 1975 Version 6 Unix for the PDP-11, running in SIMH Includes bc, chgrp, cron, newgrp, ptrace(2), ratfor, tbl, units, and wall.[4] First version widely available outside of Bell Laboratories, licensed to commercial users,[1] and to be ported to non-PDP hardware (Interdata 7/32). May 1977 saw the release of MINI-UNIX, a "cut down" v6 for the low-end PDP-11/10. 7th Edition Jan 1979 Version 7 Unix for the PDP-11, running in SIMH Includes the Bourne shell, ioctl(2), stdio(3), and pcc augmenting Dennis Ritchie's C compiler.[4] Adds adb, at, awk, banner, basename, cu, diff3, expr, f77, factor, fortune, iostat, join, lex, lint, look, m4, make, rev, sed, tabs, tail, tar, test, touch, true, false, tsort, uucp, uux. The ancestor of UNIX System III and the last release of Research Unix to see widespread external distributions. Merged most of the utilities of PWB/UNIX with an extensively modified kernel with almost 80% more lines of code than V6. Ported to PDP-11, Interdata 8/32 and VAX (UNIX/32V). 32V was the basis for 3BSD. 8th Edition Feb 1985 [citation needed] A modified 4.1cBSD[citation needed] for the VAX, with a System V shell and sockets replaced[citation needed] by Streams. Used internally, and only licensed for educational use.[7] Adds Berkeley DB, curses(3), cflow, clear, compress, cpio, csh,[8] cut, ksh[citation needed], last, netstat, netnews, seq, telnet, tset, ul, vi, vmstat. The Blit graphics terminal became the primary user interface.[4] Includes Lisp, Pascal and Altran. Added a network file system that allowed accessing remote computers' files as /n/hostname/path, and a regular expression library that introduced an API later mimicked by Henry Spencer's reimplementation.[9] First version with no assembly in the documentation.[4] 9th Edition Sep 1986 Incorporated code from 4.3BSD; used internally. Featured a generalized version of the Streams IPC mechanism introduced in V8. The mount system call was extended to connect a stream to a file, the other end of which could be connected to a (user-level) program. This mechanism was used to implement network connection code in user space.[10] Other innovations include Sam.[4] According to Dennis Ritchie, V9 and V10 were "conceptual": manuals existed, but no OS distributions "in complete and coherent form".[7] 10th Edition Oct 1989 Last Research Unix. Although the manual was published outside of AT&T by Saunders College Publishing,[11] there was no full distribution of the system itself.[7] Novelties included graphics typesetting tools designed to work with troff, a C interpreter, animation programs, and several tools later found in Plan 9: the Mk build tool and the rc shell. V10 was also the basis for Doug McIlroy and James A. Reeds' multilevel-secure operating system IX.[12] Plan 9 1992 Plan 9 was a successor operating system to Research Unix developed by Bell Laboratories Computing Science Research Center (CSRC). Inferno 1997 Inferno is a descendant of Plan 9, and shares many design concepts and even source code in the kernel, particularly around devices and the Styx/9P2000 protocol. It shares with Plan 9 the Unix heritage from Bell Labs and the Unix philosophy.

## Licensing

After the publication of the [Lions' book](/source/A_Commentary_on_the_UNIX_Operating_System), work was undertaken to release earlier versions of the [codebase](/source/Codebase). SCO first released the code under a limited educational license.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*]

Later, in January 2002, [Caldera International](/source/Caldera_International) (later to become [SCO Group](/source/SCO_Group) and made defunct) [relicensed](/source/Software_relicensing) (but has not made available) several versions under the four-clause [BSD license](/source/BSD_license), up to and including [Version 7 Unix](/source/Version_7_Unix) ([UNIX/32V](/source/UNIX%2F32V)).[13][14] As of 2022[\[update\]](https://en.wikipedia.org/w/index.php?title=Research_Unix&action=edit), there has been no widespread use of the code, but it can be used on emulator systems, and *Version 5 Unix* runs on the [Nintendo](/source/Nintendo) [Game Boy Advance](/source/Game_Boy_Advance) using the [SIMH](/source/SIMH) [PDP-11](/source/PDP-11) [emulator](/source/Emulator).[15] *Version 6 Unix* provides the basis for the MIT [xv6](/source/Xv6) teaching system, which is an update of that version to ANSI C and the x86 or RISC-V platform.

The [BSD](/source/Berkeley_Software_Distribution) [vi](/source/Vi_(text_editor)) [text editor](/source/Text_editor) is based on code from the [ed](/source/Ed_(text_editor)) line editor in those early Unixes. Therefore, "traditional" vi could not be distributed freely, and various work-alikes (such as [nvi](/source/Nvi)) were created. Now that the original code is no longer encumbered, the "traditional" vi has been adapted for modern [Unix-like](/source/Unix-like) operating systems.[16]

SCO Group, Inc. was previously called Caldera International. As a result of the *[SCO Group, Inc. v. Novell, Inc.](/source/SCO_Group%2C_Inc._v._Novell%2C_Inc.)* case, Novell, Inc. was found not to have transferred the copyrights of UNIX to SCO Group, Inc.[17] Concerns have been raised regarding the validity of the Caldera license.[18][19]

## The Unix Heritage Society

*The Unix Heritage Society* was founded by Warren Toomey.[20][21] First edition Unix was restored to a usable state by a restoration team from the Unix Heritage Society in 2008. The restoration process started with paper listings of the source code which were in PDP-11 assembly language.[22][23]

## Legacy

In 2002, [Caldera International](/source/Caldera_International) released[24] Unix V1, V2, V3, V4, V5, [V6](/source/Version_6_Unix), [V7](/source/Version_7_Unix) on [PDP-11](/source/PDP-11) and Unix 32V on [VAX](/source/VAX) as [FOSS](/source/Free_and_open_source_software) under a [permissive](/source/Permissive_license) [BSD-like](/source/BSD-license) [software license](/source/Software_license).[25][14][26]

In 2017, [The Unix Heritage Society](/source/The_Unix_Heritage_Society) and [Alcatel-Lucent](/source/Alcatel-Lucent) USA Inc., on behalf of itself and [Nokia](/source/Nokia) [Bell Laboratories](/source/Bell_Laboratories), released V8, V9, and V10 under the condition that only non-commercial use was allowed, and that they would not assert copyright claims against such use.[27]

## See also

- [History of Unix](/source/History_of_Unix)

- [List of Unix systems](/source/List_of_Unix_systems)

## References

1. ^ [***a***](#cite_ref-fiedler198310_1-0) [***b***](#cite_ref-fiedler198310_1-1) [***c***](#cite_ref-fiedler198310_1-2) [***d***](#cite_ref-fiedler198310_1-3) Fiedler, Ryan (October 1983). ["The Unix Tutorial / Part 3: Unix in the Microcomputer Marketplace"](https://archive.org/stream/byte-magazine-1983-10/1983_10_BYTE_08-10_UNIX#page/n133/mode/2up). *BYTE*. p. 132. Retrieved 30 January 2015.

1. **[^](#cite_ref-2)** Siebenmann, Chris (Nov 21, 2021). ["Why V7 Unix Matters So Much"](https://utcc.utoronto.ca/~cks/space/blog/unix/V7WhyItMattersSoMuch). *CSpace*. [Archived](https://web.archive.org/web/20250729074012/https://utcc.utoronto.ca/~cks/space/blog/unix/V7WhyItMattersSoMuch) from the original on July 29, 2025. Retrieved October 18, 2025.

1. **[^](#cite_ref-3)** Ritchie, Dennis (26 October 2000). ["alt.folklore.computers: BSD (Dennis Ritchie)"](http://yarchive.net/comp/bsd.html). [Archived](https://web.archive.org/web/20140714222327/http://yarchive.net/comp/bsd.html) from the original on 14 July 2014. Retrieved 3 July 2014.

1. ^ [***a***](#cite_ref-reader_4-0) [***b***](#cite_ref-reader_4-1) [***c***](#cite_ref-reader_4-2) [***d***](#cite_ref-reader_4-3) [***e***](#cite_ref-reader_4-4) [***f***](#cite_ref-reader_4-5) [***g***](#cite_ref-reader_4-6) [***h***](#cite_ref-reader_4-7) [***i***](#cite_ref-reader_4-8) [***j***](#cite_ref-reader_4-9) [***k***](#cite_ref-reader_4-10) [McIlroy, M. D.](/source/Doug_McIlroy) (1987). [*A Research Unix reader: annotated excerpts from the Programmer's Manual, 1971–1986*](http://www.cs.dartmouth.edu/~doug/reader.pdf) (PDF) (Technical report). CSTR. Bell Labs. 139.

1. ^ [***a***](#cite_ref-V2_5-0) [***b***](#cite_ref-V2_5-1) Thompson, Ken; Ritchie, Dennis M. (June 12, 1972). [*UNIX Programmer's Manual, Second Edition*](https://web.archive.org/web/20161006034736/http://sunsite.icm.edu.pl/pub/unix/UnixArchive/PDP-11/Distributions/research/1972_stuff/unix_2nd_edition_manual.pdf) (PDF). Bell Telephone Laboratories. Archived from [the original](http://sunsite.icm.edu.pl/pub/unix/UnixArchive/PDP-11/Distributions/research/1972_stuff/unix_2nd_edition_manual.pdf) (PDF) on 2016-10-06.

1. **[^](#cite_ref-6)** Ritchie, D. M.; Thompson, K. (1974). ["The UNIX Time-Sharing System"](https://www.bell-labs.com/usr/dmr/www/cacm.html). *Communications of the ACM*. **17** (7): 365–375. [doi](/source/Doi_(identifier)):[10.1145/361011.361061](https://doi.org/10.1145%2F361011.361061). [S2CID](/source/S2CID_(identifier)) [53235982](https://api.semanticscholar.org/CorpusID:53235982). [Archived](https://web.archive.org/web/20170218050938/http://www.bell-labs.com/usr/dmr/www/cacm.html) from the original on 2017-02-18. Retrieved 2017-03-04.

1. ^ [***a***](#cite_ref-dmrV8910_7-0) [***b***](#cite_ref-dmrV8910_7-1) [***c***](#cite_ref-dmrV8910_7-2) [Ritchie, Dennis](/source/Dennis_Ritchie) (27 June 2003). ["\[TUHS\] Re: V7 UNIX on VAX 11/750"](https://web.archive.org/web/20170305042336/http://minnie.tuhs.org/pipermail/tuhs/2003-June/002195.html). *minnie.tuhs.org*. Archived from [the original](http://minnie.tuhs.org/pipermail/tuhs/2003-June/002195.html) on 2017-03-05. Retrieved 9 April 2014.

1. **[^](#cite_ref-8)** ["csh"](https://minnie.tuhs.org/cgi-bin/utree.pl?file=V8/usr/src/cmd/csh). *[The Unix Heritage Society](/source/The_Unix_Heritage_Society)*. n.d. [Archived](https://web.archive.org/web/20221220030733/https://minnie.tuhs.org/cgi-bin/utree.pl?file=V8/usr/src/cmd/csh) from the original on December 20, 2022. Retrieved December 19, 2022.

1. **[^](#cite_ref-9)** Spencer, Henry (1986-01-19). ["regexp(3)"](https://groups.google.com/forum/#!original/mod.sources/OqVZYQNSmDs/G_T2jHu5QI8J). [Newsgroup](/source/Usenet_newsgroup): [mod.sources](news:mod.sources). [Usenet:](/source/Usenet_(identifier)) [1316@panda.UUCP](news:1316@panda.UUCP). [Archived](https://web.archive.org/web/20250915161221/https://groups.google.com/forum/#!original/mod.sources/OqVZYQNSmDs/G_T2jHu5QI8J) from the original on 2025-09-15. Retrieved 9 January 2013.

1. **[^](#cite_ref-10)** Presotto, David L.; Ritchie, Dennis M. (1990). ["Interprocess Communication in the Ninth Edition Unix System"](https://www.bell-labs.com/usr/dmr/www/ipcpaper.html). *[Software: Practice and Experience](https://en.wikipedia.org/w/index.php?title=Software:_Practice_and_Experience&action=edit&redlink=1)*. **19**. [Archived](https://web.archive.org/web/20170403063718/https://www.bell-labs.com/usr/dmr/www/ipcpaper.html) from the original on 2017-04-03. Retrieved 2017-03-04.

1. **[^](#cite_ref-11)** ["Unix Tenth Edition Manual"](https://web.archive.org/web/20150203070035/http://www.cs.bell-labs.com/10thEdMan/). [Bell Labs](/source/Bell_Labs). Archived from [the original](http://www.cs.bell-labs.com/10thEdMan) on 3 February 2015. Retrieved 25 December 2013.

1. **[^](#cite_ref-12)** ["The IX Multilevel-Secure UNIX System"](http://www.cs.dartmouth.edu/~doug/IX/). [Archived](https://web.archive.org/web/20150923211409/http://www.cs.dartmouth.edu/~doug/IX/) from the original on 2015-09-23. Retrieved 2013-12-25.

1. **[^](#cite_ref-13)** Johnson II, Dion L. (2002-01-24). ["Liberal license for ancient UNIX sources"](http://www.lemis.com/grog/UNIX/). [Archived](https://web.archive.org/web/20220305150312/http://www.lemis.com/grog/UNIX/) from the original on 2022-03-05. Retrieved 2017-03-30.

1. ^ [***a***](#cite_ref-Caldera-license.pdf_14-0) [***b***](#cite_ref-Caldera-license.pdf_14-1) Broderick, Bill (January 23, 2002). ["Dear Unix enthusiasts"](https://web.archive.org/web/20090219220353/http://www.tuhs.org/Archive/Caldera-license.pdf) (PDF). [Caldera International](/source/Caldera_International). Archived from [the original](http://www.tuhs.org/Archive/Caldera-license.pdf) (PDF) on 19 February 2009.

1. **[^](#cite_ref-gbaunix_15-0)** Singh, Amit (August 2004). ["UNIX® on the Game Boy Advance"](https://web.archive.org/web/20060831141959/http://www.kernelthread.com/publications/gbaunix/). Archived from [the original](http://www.kernelthread.com/publications/gbaunix/) on 2006-08-31. Retrieved 2009-10-22.

1. **[^](#cite_ref-16)** ["The Traditional Vi"](https://ex-vi.sourceforge.net/). [Archived](https://web.archive.org/web/20250813052344/https://ex-vi.sourceforge.net/) from the original on 2025-08-13. Retrieved 2025-08-11.

1. **[^](#cite_ref-17)** ["10th Circuit Court of Appeals Decision"](https://web.archive.org/web/20110926220558/http://www.groklaw.net/pdf3/SCOvNovell10-4122.pdf) (PDF). Archived from the original on September 26, 2011.

1. **[^](#cite_ref-18)** Warren Toomey. ["The Push to Get Free Unix Licenses"](https://wiki.tuhs.org//doku.php?id=events:free_licenses). [Archived](https://web.archive.org/web/20250520232649/https://wiki.tuhs.org/doku.php?id=events:free_licenses) from the original on 2025-05-20. Retrieved 2025-06-15.

1. **[^](#cite_ref-19)** ["Why BSD/OS is the best candidate for being the only tested legally open UNIX"](https://virtuallyfun.com/wordpress/2018/11/26/why-bsd-os-is-the-best-candidate-for-being-the-only-tested-legally-open-unix/). 26 November 2018. [Archived](https://web.archive.org/web/20250615084518/https://virtuallyfun.com/wordpress/2018/11/26/why-bsd-os-is-the-best-candidate-for-being-the-only-tested-legally-open-unix/) from the original on 15 June 2025. Retrieved 15 June 2025.

1. **[^](#cite_ref-lwn.net/725297_20-0)** Davis, A. Jesse Jiryu (June 14, 2017). ["Assembling the history of Unix"](https://lwn.net/Articles/725297/). *LWN.net*. [Archived](https://web.archive.org/web/20230615220253/https://lwn.net/Articles/725297/) from the original on 15 June 2023. Retrieved 15 June 2023.

1. **[^](#cite_ref-bsdnow.tv/476_21-0)** Jude, Allan (October 13, 2022). ["Warren Toomey interview"](https://www.bsdnow.tv/476). *BSD Now*. [Archived](https://web.archive.org/web/20230615220257/https://www.bsdnow.tv/476) from the original on 15 June 2023. Retrieved 15 June 2023. [MP3 44:34](https://aphid.fireside.fm/d/1437767933/c91b88f1-e824-4815-bcb8-5227818d6010/64bc3a0c-43cf-4e97-af97-b31d799c1154.mp3)

1. **[^](#cite_ref-22)** Toomey, Warren (July 2010). "First Edition Unix: Its Creation and Restoration". *IEEE Annals of the History of Computing*. **32** (3): 74–82. [Bibcode](/source/Bibcode_(identifier)):[2010IAHC...32c..74T](https://ui.adsabs.harvard.edu/abs/2010IAHC...32c..74T). [doi](/source/Doi_(identifier)):[10.1109/MAHC.2009.55](https://doi.org/10.1109%2FMAHC.2009.55). [S2CID](/source/S2CID_(identifier)) [18586380](https://api.semanticscholar.org/CorpusID:18586380).

1. **[^](#cite_ref-23)** ["The Restoration of Early UNIX Artifacts"](https://www.usenix.org/legacy/events/usenix09/tech/full_papers/toomey/toomey.pdf) (PDF). [Archived](https://web.archive.org/web/20250627095821/https://www.usenix.org/legacy/events/usenix09/tech/full_papers/toomey/toomey.pdf) (PDF) from the original on 2025-06-27. Retrieved 2025-06-15.

1. **[^](#cite_ref-24)** [Caldera releases original unices under BSD license](http://slashdot.org/articles/02/01/24/0146248.shtml) [Archived](https://web.archive.org/web/20081012193225/http://slashdot.org/articles/02/01/24/0146248.shtml) 2008-10-12 at the [Wayback Machine](/source/Wayback_Machine) on [slashdot.org](/source/Slashdot.org) (2002)

1. **[^](#cite_ref-25)** ["UNIX is free!"](http://www.lemis.com/grog/UNIX/). lemis.com. 2002-01-24. [Archived](https://web.archive.org/web/20220305150312/http://www.lemis.com/grog/UNIX/) from the original on 2022-03-05. Retrieved 2017-03-30.

1. **[^](#cite_ref-26)** Darwin, Ian F. (2002-02-03). ["Why Caldera Released Unix: A Brief History"](https://web.archive.org/web/20040601025000/http://www.linuxdevcenter.com/pub/a/linux/2002/02/28/caldera.html). *Linuxdevcenter*. [O'Reilly Media](/source/O'Reilly_Media). Archived from [the original](http://www.linuxdevcenter.com/pub/a/linux/2002/02/28/caldera.html) on 2004-06-01. Retrieved 2022-01-18.

1. **[^](#cite_ref-27)** Chirgwin, Richard (30 March 2017). ["Samizdat no more: Old Unix source code opened for study"](https://www.theregister.co.uk/2017/03/30/old_unix_source_code_opened_for_study/). *[The Register](/source/The_Register)*. [Archived](https://web.archive.org/web/20170330134247/https://www.theregister.co.uk/2017/03/30/old_unix_source_code_opened_for_study/) from the original on 30 March 2017. Retrieved 30 March 2017.

## External links

Wikimedia Commons has media related to [Research Unix](https://commons.wikimedia.org/wiki/Category:Research_Unix).

- [UNIX Evolution](http://www.collyer.net/who/geoff/history.html) ([PostScript](http://www.collyer.net/who/geoff/history.ps)) by Ian F. Darwin and Geoffrey Collyer

- [Unix heritage](http://www.tuhs.org/) - More links and source code for some Research Unix versions

- [The Evolution of the Unix Time-sharing System](https://www.bell-labs.com/usr/dmr/www/hist.html) by [Dennis M. Ritchie](/source/Dennis_M._Ritchie)

- [The Restoration of Early UNIX Artifacts](http://www.usenix.org/events/usenix09/tech/full_papers/toomey/toomey.pdf) by Warren Toomey, School of IT, Bond University

- [Full Manual Pages documentation for Research Unix 8th Edition](http://man.cat-v.org/unix_8th/).

- [List of new features in Research Unix 9th Edition](https://groups.google.com/forum/#!original/comp.unix.wizards/9iC6Z3LboDA/AVjXvtLxpcMJ).

- [Emulator for running UNIX v9](https://github.com/ambiamber/Run-UNIX-v9).

- [Pamela Jones](/source/Pamela_Jones) (August 23, 2003) [Ancient UNIX Released Under What Terms?](https://www.tech-insider.org/internet/research/2003/0823.html), [Groklaw](/source/Groklaw)

- [The Unix Heritage Society (TUHS)](https://www.tuhs.org/), for the preservation and maintenance of historical UNIX systems - [code, disk images, and related](https://minnie.tuhs.org/UnixTree/) at TUHS

- [Unix First Edition Manual Pages](http://man.cat-v.org/unix-1st/)

- [Restoration of 1st Edition UNIX kernel sources from Bell Laboratories](https://github.com/jserv/unix-v1)

v t e Unix by Bell Labs Research Version 6 Unix (1975) Version 7 Unix (1979) UNIX/32V (1979) Internal CB UNIX (c. 1975) PWB/UNIX (1977) MERT/DMERT/UNIX-RT Commercial UNIX System III (1982) UNIX System V (1983) People Stephen R. Bourne Lorinda Cherry Tom Duff Stuart Feldman Brian Kernighan David Korn Mike Lesk John Mashey Douglas McIlroy Lee E. McMahon Joe Ossanna Rob Pike Dennis Ritchie Ken Thompson Companies AT&T Computer Systems Unix System Laboratories Category

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Adapted from the Wikipedia article [Research Unix](https://en.wikipedia.org/wiki/Research_Unix) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Research_Unix?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.