Research Unix refers to the early versions of theUnix operating system forDEC PDP-7,PDP-11,VAX, andInterdata 7/32 and 8/32 computers, developed in theBell Labs Computing Sciences Research Center (CSRC). The termResearch Unix first appeared in theBell System Technical Journal (Vol. 57, No. 6, Part 2 July/August 1978) to distinguish it from other versions internal to Bell Labs (such asPWB/UNIX andMERT) whose code-base had diverged from the primary CSRC version. However, that term was little-used until Version 8 Unix (1985), but has beenretroactively 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 theUnix code base prior to UnixSystem III, particularly the Research Unix releases prior to and including Version 7 (the base forUNIX/32V as well as later developments ofAT&T Unix).
AT&T 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 themanual 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 "Versionx Unix" or "Vx Unix", wherex is the manual edition. All modern editions of Unix—exceptingUnix-like implementations such asCoherent,Minix, andLinux—derive from the 7th Edition.[2]
Starting with the 8th Edition, versions of Research Unix had a close relationship toBSD. This began by using 4.1cBSD as the basis for the 8th Edition. In aUsenet post from 2000,Dennis Ritchie described these later versions of Research Unix as being closer to BSD than they were toUNIX 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.
| 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. Includesar,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 offsck,reboot, andadb. The system also had aB andFortrancompiler, aBASIC interpreter,device files and functions for managingpunched tape,DECtape, andRK05 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 Addsecho,exit,login, m6macro processor,man,nroff,strip,stty,tmg compiler-compiler and the firstC compiler.[4][5] |
| 3rd Edition | Feb 1973 | Introduced a Cdebugger,pipes,crypt,kill,passwd, size,speak,split,uniq, andyacc. Commands are split between /bin and /usr/bin, requiring asearch 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 introducedcomm,dump,file,grep,nice,nohup,ps,sleep,sync,tr,wait, andprintf(3).[4] Included aSNOBOL interpreter. Number of installations was listed as "above 20". The manual was formatted withtroff for the first time. Version described in Thompson and Ritchie'sCACM paper,[6] the first public exposition of the operating system.[4] |
| 5th Edition | Jun 1974 |  Licensed to selected educational institutions.[1] Introducedcol,dd,diff,eqn,find,lpr,pwd,spell,tee,[4] and thesticky bit. Targeted the PDP-11/40 and other 11 models with 18 bit addresses. Installations "above 50". |
| 6th Edition | May 1975 |  Includesbc,chgrp,cron,newgrp,ptrace(2),ratfor,tbl,units, andwall.[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 |  Includes theBourne shell,ioctl(2),stdio(3), andpcc augmentingDennis Ritchie's C compiler.[4] Addsadb,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 ofUNIX System III and the last release of Research Unix to see widespread external distributions. Merged most of the utilities ofPWB/UNIX with an extensively modified kernel with almost 80% more lines of code than V6. Ported toPDP-11,Interdata 8/32 andVAX (UNIX/32V). 32V was the basis for3BSD. |
| 8th Edition | Feb 1985 [citation needed] | A modified 4.1cBSD[citation needed] for theVAX, with aSystem V shell andsockets replaced[citation needed] byStreams. Used internally, and only licensed for educational use.[7] AddsBerkeley DB,curses(3),cflow,clear,compress,cpio,csh,[8]cut,ksh[citation needed],last,netstat,netnews,seq,telnet,tset,ul,vi,vmstat. TheBlit graphics terminal became the primary user interface.[4] IncludesLisp,Pascal andAltran. Added anetwork file system that allowed accessing remote computers' files as /n/hostname/path, and a regular expression library that introduced an API later mimicked byHenry 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 theStreamsIPC 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 includeSam.[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 graphicstypesetting tools designed to work withtroff, aCinterpreter, animation programs, and several tools later found in Plan 9: theMk build tool and therc shell. V10 was also the basis forDoug 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. |
After the publication of theLions' book, work was undertaken to release earlier versions of thecodebase. SCO first released the code under a limited educational license.[citation needed]
Later, in January 2002,Caldera International (later to becomeSCO Group and made defunct)relicensed (but has not made available) several versions under the four-clauseBSD license, up to and includingVersion 7 Unix (UNIX/32V).[13][14] As of 2022[update], there has been no widespread use of the code, but it can be used on emulator systems, andVersion 5 Unix runs on theNintendoGame Boy Advance using theSIMHPDP-11emulator.[15]Version 6 Unix provides the basis for the MITxv6 teaching system, which is an update of that version to ANSI C and the x86 or RISC-V platform.
TheBSDvitext editor is based on code from theed line editor in those early Unixes. Therefore, "traditional" vi could not be distributed freely, and various work-alikes (such asnvi) were created. Now that the original code is no longer encumbered, the "traditional" vi has been adapted for modernUnix-like operating systems.[16]
SCO Group, Inc. was previously called Caldera International. As a result of theSCO Group, Inc. v. Novell, 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 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]
In 2002,Caldera International released[24] Unix V1, V2, V3, V4, V5,V6,V7 onPDP-11 and Unix 32V onVAX asFOSS under apermissiveBSD-likesoftware license.[25][14][26]
In 2017,The Unix Heritage Society andAlcatel-Lucent USA Inc., on behalf of itself andNokiaBell 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]
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