Sixth Edition Unix, also called Version 6 Unix or just V6, was the first version of the
Unix
Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and ot ...
operating system
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...
to see wide release outside
Bell Labs
Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984),
then AT&T Bell Laboratories (1984–1996)
and Bell Labs Innovations (1996–2007),
is an American industrial research and scientific development company owned by mult ...
. It was released in May 1975 and, like its direct predecessor, targeted the
DEC PDP-11
The PDP-11 is a series of 16-bit minicomputers sold by Digital Equipment Corporation (DEC) from 1970 into the 1990s, one of a set of products in the Programmed Data Processor (PDP) series. In total, around 600,000 PDP-11s of all models were sold, ...
family of
minicomputer
A minicomputer, or colloquially mini, is a class of smaller general purpose computers that developed in the mid-1960s and sold at a much lower price than mainframe and mid-size computers from IBM and its direct competitors. In a 1970 survey, ...
s. It was superseded by
Version 7 Unix
Seventh Edition Unix, also called Version 7 Unix, Version 7 or just V7, was an important early release of the Unix operating system. V7, released in 1979, was the last Bell Laboratories release to see widespread distribution before the commercial ...
in 1978/1979, although V6 systems remained in regular operation until at least 1985.
AT&T Corporation
AT&T Corporation, originally the American Telephone and Telegraph Company, is the subsidiary of AT&T Inc. that provides voice, video, data, and Internet telecommunications and professional services to businesses, consumers, and government agen ...
licensed
Version 5 Unix
The term "Research Unix" refers to early versions of the Unix operating system for PDP-7, DEC PDP-7, PDP-11, VAX and Interdata 7/32 and 8/32 computers, developed in the Bell Labs Computing Sciences Research Center (CSRC).
History
The term ''Re ...
to educational institutions only, but licensed Version 6 also to commercial users for $20,000, and it remained the most widely used version into the 1980s.
An enhanced V6 was the basis of the first ever commercially sold Unix version,
INTERACTIVE
Across the many fields concerned with interactivity, including information science, computer science, human-computer interaction, communication, and industrial design, there is little agreement over the meaning of the term "interactivity", but mo ...
's IS/1. Bell's own
PWB/UNIX
The Programmer's Workbench (PWB/UNIX) is an early, now discontinued, version of the Unix operating system that had been created in the Bell Labs Computer Science Research Group of AT&T. Its stated goal was to provide a time-sharing working envir ...
1.0 was also based on V6, where earlier (unreleased) versions were based on V4 and V5.
Whitesmiths
Whitesmiths Ltd. was a software company founded in New York City by P. J. Plauger, Mark Krieger and Gabriel Pham, and last located in Westford, Massachusetts. It sold a Unix-like operating system called Idris (operating system), Idris, as well as ...
produced and marketed a (binary-compatible) V6 clone under the name
Idris Idris may refer to:
People
* Idris (name), a list of people and fictional characters with the given name or surname
* Idris (prophet), Islamic prophet in the Qur'an, traditionally identified with Enoch, an ancestor of Noah in the Bible
* Idris G ...
.
Source code
![Version 6 Unix SIMH PDP11 Emulation Source](https://upload.wikimedia.org/wikipedia/commons/5/54/Version_6_Unix_SIMH_PDP11_Emulation_Source.png)
V6 Unix was released as a distribution including the full
source code
In computing, source code, or simply code, is any collection of code, with or without comments, written using a human-readable programming language, usually as plain text. The source code of a program is specially designed to facilitate the wo ...
. Since source code was available and the license was not explicit enough to forbid it, V6 was taken up as a teaching tool, notably by the
University of California, Berkeley
The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California) is a public land-grant research university in Berkeley, California. Established in 1868 as the University of California, it is the state's first land-grant u ...
,
Johns Hopkins University
Johns Hopkins University (Johns Hopkins, Hopkins, or JHU) is a private university, private research university in Baltimore, Maryland. Founded in 1876, Johns Hopkins is the oldest research university in the United States and in the western hem ...
and the
University of New South Wales
The University of New South Wales (UNSW), also known as UNSW Sydney, is a public research university based in Sydney, New South Wales, Australia. It is one of the founding members of Group of Eight, a coalition of Australian research-intensive ...
(UNSW).
UC Berkeley distributed a set of add-on programs called the
First Berkeley Software Distribution or 1BSD, which later became a complete operating system distribution.
UNSW professor
John Lions
John Lions (19 January 1937 – 5 December 1998) was an Australian computer scientist. He is best known as the author of ''Lions' Commentary on UNIX 6th Edition, with Source Code'', commonly known as the ''Lions Book''.
Early life
Lions ga ...
' famous
''Commentary on UNIX 6th Edition'' was an edited selection of the main parts of the kernel as implemented for a Digital PDP-11/40, and was the main source of kernel documentation for many early Unix developers. Due to license restrictions on later Unix versions, the book was mainly distributed by ''
samizdat
Samizdat (russian: самиздат, lit=self-publishing, links=no) was a form of dissident activity across the Eastern Bloc in which individuals reproduced censored and underground makeshift publications, often by hand, and passed the document ...
'' photo-copying.
The source code for the original V6 Unix was later made available as
free software
Free software or libre software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, no ...
under a
BSD License
BSD licenses are a family of permissive free software licenses, imposing minimal restrictions on the use and distribution of covered software. This is in contrast to copyleft licenses, which have share-alike requirements. The original BSD lic ...
from the
SCO Group
The SCO Group (often referred to SCO and later called The TSG Group) was an American software company in existence from 2002 to 2012 that became known for owning Unix operating system assets that had belonged to the Santa Cruz Operation (the o ...
.
Portability
Interdata 7/32
In 1977, Richard Miller and Ross Nealon, working under the supervision of professor Juris Reinfelds at
Wollongong University
The University of Wollongong (abbreviated as UOW) is an Australian public university, public research university located in the coastal city of Wollongong, New South Wales, approximately 80 kilometres south of Sydney. As of 2017, the university ...
, completed a port of V6 Unix to the
Interdata 7/32
The Model 7/32 and Model 8/32 were 32-bit minicomputers introduced by Perkin-Elmer after they acquired Interdata, Inc., in 1973. Interdata computers are primarily remembered for being the first 32-bit minicomputers under $10,000. The 8/32 was a m ...
, thus proving the portability of Unix and its new systems programming language
C in practice. Their "Wollongong Interdata UNIX, Level 6" also included utilities developed at Wollongong, and later releases had features of V7, notably its
C compiler
In computing, a compiler is a computer program that translates computer code written in one programming language (the ''source'' language) into another language (the ''target'' language). The name "compiler" is primarily used for programs that ...
. Wollongong Unix was the first ever port to a platform other than the PDP series of computers, proving that portable operating systems were indeed feasible, and that C was the language in which to write them. In 1980, this version was licensed to
The Wollongong Group The Wollongong Group (TWG) was one of the firscompaniesto sell commercial software products based on the Unix operating system. It was founded to market a port of Unix Version 6 developed by researchers at the University of Wollongong, Australia (t ...
in Palo Alto that published it as Edition 7.
Interdata 8/32
Around the same time, a Bell Labs port to the Interdata 8/32 was completed, but not externally released. The goal of this port was to improve the portability of Unix more generally, as well to produce a portable version of the C compiler.
The resulting
Portable C Compiler
The Portable C Compiler (also known as pcc or sometimes pccm - portable C compiler machine) is an early compiler for the C programming language written by Stephen C. Johnson of Bell Labs in the mid-1970s, based in part on ideas proposed by Alan ...
(PCC) was distributed with V7 and many later versions of Unix, and was used to produce the
UNIX/32V
UNIX/32V is an early version of the Unix operating system from Bell Laboratories, released in June 1979. 32V was a direct port of the Seventh Edition Unix to the DEC VAX architecture.
Overview
Before 32V, Unix had primarily run on DEC PDP-11 ...
port to the
VAX
VAX (an acronym for Virtual Address eXtension) is a series of computers featuring a 32-bit instruction set architecture (ISA) and virtual memory that was developed and sold by Digital Equipment Corporation (DEC) in the late 20th century. The VA ...
.
IBM VM/370
A third Unix portability project was completed at
Princeton, NJ
Princeton is a municipality with a borough form of government in Mercer County, in the U.S. state of New Jersey. It was established on January 1, 2013, through the consolidation of the Borough of Princeton and Princeton Township, both of whic ...
in 1976–1977, where the Unix kernel was adapted to run as a guest operating on IBM's
VM/370
VM (often: VM/CMS) is a family of IBM virtual machine operating systems used on IBM mainframes System/370, System/390, zSeries, System z and compatible systems, including the Hercules emulator for personal computers.
The following versions ...
virtualization environment.
This version became the nucleus of Amdahl's first internal UNIX offering. (see
Amdahl UTS
UTS is a discontinued implementation of the UNIX operating system for IBM mainframe (and compatible) computers. Amdahl created the first versions of UTS, and released it in May 1981, with UTS Global acquiring rights to the product in 2002. UTS Gl ...
)
Variants and extensions
Bell Labs developed several variants of V6, including the stripped-down MINI-UNIX for low-end PDP-11 models, LSI-UNIX or LSX for the
LSI-11
The PDP-11 is a series of 16-bit minicomputers sold by Digital Equipment Corporation (DEC) from 1970 into the 1990s, one of a set of products in the Programmed Data Processor (PDP) series. In total, around 600,000 PDP-11s of all models were sold, ...
, and the
real-time operating system
A real-time operating system (RTOS) is an operating system (OS) for real-time applications that processes data and events that have critically defined time constraints. An RTOS is distinct from a time-sharing operating system, such as Unix, which m ...
UNIX/RT, which merged V6 Unix and the earlier
MERT Mert may refer to:
People Given name
* Mert (given name), a Turkish masculine given name.
Surname
* Bahar Mert (born 1975), Turkish volleyball player born in Bulgaria
* Mesut Mert (born 1978), Canadian association football player and coach of ...
hypervisor.
After AT&T decided the distribution by Bell Labs of a number of pre-V7 bug fixes would constitute support (disallowed by an antitrust settlement) a tape with the patchset was slipped to Lou Katz of
USENIX, who distributed them.
The
University of Sydney
The University of Sydney (USYD), also known as Sydney University, or informally Sydney Uni, is a public research university located in Sydney, Australia. Founded in 1850, it is the oldest university in Australia and is one of the country's si ...
released the Australian Unix Share Accounting Method (AUSAM) in November 1979, a V6 variant with improved security and process accounting.
In the
Eastern Bloc
The Eastern Bloc, also known as the Communist Bloc and the Soviet Bloc, was the group of socialist states of Central and Eastern Europe, East Asia, Southeast Asia, Africa, and Latin America under the influence of the Soviet Union that existed du ...
, clones of V6 Unix appeared for local-built PDP-11 clones (
MNOS, later augmented for partial compatibility with BSD Unix) and for the
Elektronika BK
The Electronika BK is a series of 16-bit PDP-11-compatible home computers developed under the Electronika brand by NPO Scientific Center, then the leading microcomputer design team in the Soviet Union. It is also the predecessor of the more power ...
personal computer (
BKUNIX, based on LSX).
V6 was used for teaching at
MIT
The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the mo ...
in 2002 through 2006, and subsequently replaced by a simpler clone called
xv6
xv6 is a modern reimplementation of Sixth Edition Unix in ANSI C for multiprocessor x86 and RISC-V systems. It was created for pedagogical purposes in MIT's Operating System Engineering course in 2006.
Purpose
MIT's Operating System Engineerin ...
.
See also
*
Ancient UNIX
Ancient UNIX is any early release of the Unix code base prior to Unix System III, particularly the Research Unix releases prior to and including Version 7 (the base for UNIX/32V as well as later developments of AT&T Unix).
After the publicati ...
References
External links
V6 source codeWollongong Interdata UNIX source codeUnix V6 Manuals– Web interface to the V6 manual pages.
Unix V6 documents, e.g. C Reference, and man pagesThe First Unix Port Richard Miller's account of porting Unix to the Interdata 7/32
Unix v6 for PDP-11 online emulator
{{Unix-like
Bell Labs Unices
Discontinued operating systems
Unix history
Unix variants
Free software operating systems
1975 software