Seventh Edition Unix, also called Version 7 Unix, Version 7 or just V7, was an important early release 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 ...

. V7, released in 1979, was the last

Bell Laboratories 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 ...

release to see widespread distribution before the commercialization of Unix by

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 ...

in the early 1980s. V7 was originally developed for

Digital Equipment Corporation Digital Equipment Corporation (DEC ), using the trademark Digital, was a major American company in the computer industry from the 1960s to the 1990s. The company was co-founded by Ken Olsen and Harlan Anderson in 1957. Olsen was president unt ...

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, ...

minicomputers and was later ported to other platforms.

Overview

Unix versions from Bell Labs were designated by the edition of the user's manual with which they were accompanied. Released in 1979, the Seventh Edition was preceded by Sixth Edition, which was the first version licensed to commercial users. Development of the

Research Unix The term "Research Unix" refers to early versions of the Unix operating system for 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 ''Research ...

line continued with the Eighth Edition, which incorporated development from 4.1BSD, through the Tenth Edition, after which the Bell Labs researchers concentrated on developing Plan 9. V7 was the first readily

portable Portable may refer to: General * Portable building, a manufactured structure that is built off site and moved in upon completion of site and utility work * Portable classroom, a temporary building installed on the grounds of a school to provide ...

version of Unix. As this was the era 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, with their many architectural variations, and also the beginning of the market for 16-bit microprocessors, many ports were completed within the first few years of its release. The first

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

workstations (then based on the

Motorola 68000 The Motorola 68000 (sometimes shortened to Motorola 68k or m68k and usually pronounced "sixty-eight-thousand") is a 16/32-bit complex instruction set computer (CISC) microprocessor, introduced in 1979 by Motorola Semiconductor Products Sector ...

) ran a V7 port by

UniSoft UniSoft Corporation is an American software developer established in 1981, originally focused on the development of Unix ports for various computer architectures. Based in Millbrae, California, it now builds standardization and conformance test ...

; the first version of

Xenix Xenix is a discontinued version of the Unix operating system for various microcomputer platforms, licensed by Microsoft from AT&T Corporation in the late 1970s. The Santa Cruz Operation (SCO) later acquired exclusive rights to the software, and ...

for the

Intel 8086 The 8086 (also called iAPX 86) is a 16-bit microprocessor chip designed by Intel between early 1976 and June 8, 1978, when it was released. The Intel 8088, released July 1, 1979, is a slightly modified chip with an external 8-bit data bus (allowi ...

was derived from V7 and

Onyx Systems Onyx primarily refers to the parallel banded variety of chalcedony, a silicate mineral. Agate and onyx are both varieties of layered chalcedony that differ only in the form of the bands: agate has curved bands and onyx has parallel bands. The c ...

soon produced a

Zilog Zilog, Inc. is an American manufacturer of microprocessors and 8-bit and 16-bit microcontrollers. It is also a supplier of application-specific embedded system-on-chip (SoC) products. Its most famous product is the Z80 series of 8-bit microp ...

Z8000 computer running V7. 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 V ...

port of V7, called

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 ...

, was the direct ancestor of the popular 4BSD family of Unix systems. The group at the

University of Wollongong The University of Wollongong (abbreviated as UOW) is an Australian public research university located in the coastal city of Wollongong, New South Wales, approximately 80 kilometres south of Sydney. As of 2017, the university had an enrolment of ...

that had ported V6 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 ...

ported V7 to that machine as well.

Interdata Interdata, Inc., was a computer company, founded in 1966 by a former Electronic Associates engineer, Daniel Sinnott, and was based in Oceanport, New Jersey. The company produced a line of 16- and 32-bit minicomputers that were loosely based on t ...

sold the port as Edition VII, making it the first commercial UNIX offering. DEC distributed their own PDP-11 version of V7, called V7M (for modified). V7M, developed by DEC's original Unix Engineering Group (UEG), contained many enhancements to the kernel for the PDP-11 line of computers including significantly improved hardware error recovery and many additional device drivers. UEG evolved into the group that later developed

Ultrix Ultrix (officially all-caps ULTRIX) is the brand name of Digital Equipment Corporation's (DEC) discontinued native Unix operating systems for the PDP-11, VAX, MicroVAX and DECstations. History The initial development of Unix occurred on DEC equip ...

Reception

Due to its power yet elegant simplicity, many old-time Unix users remember V7 as the pinnacle of Unix development and have dubbed it "the last true Unix", an improvement over all preceding and following Unices. At the time of its release, though, its greatly extended feature set came at the expense of a decrease in performance compared to V6, which was to be corrected largely by the user community. The number of

system call In computing, a system call (commonly abbreviated to syscall) is the programmatic way in which a computer program requests a service from the operating system on which it is executed. This may include hardware-related services (for example, acc ...

s in Version 7 was only around 50, while later Unix and Unix-like systems continued to add many more:

Released as free software

In 2002,

Caldera International Caldera International, Inc., earlier Caldera Systems, was an American software company that existed from 1998 to 2002 and developed and sold Linux- and Unix-based operating system products. Caldera Systems was created in August 1998 as a spinoff ...

released V7 as

FOSS Fos or FOSS may refer to: Companies * Foss A/S, a Danish analytical instrument company *Foss Brewery, a former brewery in Oslo, Norway * Foss Maritime, a tugboat and shipping company Historic houses * Foss House (New Brighton, Minnesota), Unite ...

under a

permissive {{about, , the 1970 British film, Permissive (film), the grammatical mode, Permissive mood, the flavor of software license, permissive free software licence A permissive cell or host is one that allows a virus to circumvent its defenses and replica ...

BSD-like

software license A software license is a legal instrument (usually by way of contract law, with or without printed material) governing the use or redistribution of software. Under United States copyright law, all software is copyright protected, in both source ...

. Bootable images for V7 can still b
downloaded
today, and can be run on modern hosts using PDP-11 emulators such as

SIMH SIMH is a free and open source, multi-platform multi-system emulator. It is maintained by Bob Supnik, a former DEC engineer and DEC vice president, and has been in development in one form or another since the 1960s. History SIMH was based on ...

. An

x86 x86 (also known as 80x86 or the 8086 family) is a family of complex instruction set computer (CISC) instruction set architectures initially developed by Intel based on the Intel 8086 microprocessor and its 8088 variant. The 8086 was introd ...

port has been developed by Nordier & Associates.

Paul Allen Paul Gardner Allen (January 21, 1953 – October 15, 2018) was an American business magnate, computer programmer, researcher, investor, and philanthropist. He co-founded Microsoft Corporation with childhood friend Bill Gates in 1975, which h ...

maintained several publicly accessible historic computer systems, including a PDP-11/70 running Unix Version 7.

New features in Version 7

Many new features were introduced in Version 7. *Programming tools:

lex Lex or LEX may refer to: Arts and entertainment * ''Lex'', a daily featured column in the ''Financial Times'' Games * Lex, the mascot of the word-forming puzzle video game ''Bookworm'' * Lex, the protagonist of the word-forming puzzle video ga ...

, lint, and

make Make or MAKE may refer to: * Make (magazine), a tech DIY periodical *Make (software), a software build tool *Make, Botswana, in the Kalahari Desert *Make Architects Make Architects is an international architecture practice headquartered in Londo ...

The

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 provided along with the earlier, PDP-11-specific, C compiler by Ritchie.

These first appeared in the Research Unix lineage in Version 7, although early versions of some of them had already been picked up by

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 ...

. *New commands: the

Bourne shell The Bourne shell (sh) is a Shell (computing), shell Command-line interface#Command-line interpreter, command-line interpreter for computer operating systems. The Bourne shell was the default Unix shell, shell for Version 7 Unix. Unix-like syste ...

, at,

awk AWK (''awk'') is a domain-specific language designed for text processing and typically used as a data extraction and reporting tool. Like sed and grep, it is a filter, and is a standard feature of most Unix-like operating systems. The AWK lang ...

, calendar, f77,

fortune Fortune may refer to: General * Fortuna or Fortune, the Roman goddess of luck * Luck * Wealth * Fortune, a prediction made in fortune-telling * Fortune, in a fortune cookie Arts and entertainment Film and television * ''The Fortune'' (1931 film) ...

tar Tar is a dark brown or black viscous liquid of hydrocarbons and free carbon, obtained from a wide variety of organic materials through destructive distillation. Tar can be produced from coal, wood, petroleum, or peat. "a dark brown or black bit ...

(replacing the tp command), touch *Networking support, in the form of

uucp UUCP is an acronym of Unix-to-Unix Copy. The term generally refers to a suite of computer programs and protocols allowing remote execution of commands and transfer of files, email and netnews between computers. A command named is one of the prog ...

and

Datakit Datakit is a virtual circuit switch which was developed by Sandy Fraser at Bell Labs for both local-area and wide-area networks, and in widespread deployment by the Regional Bell Operating Companies (RBOCs). Datakit uses a cell relay protocol simi ...

*New

s: access, acct, alarm,

chroot A chroot on Unix and Unix-like operating systems is an operation that changes the apparent root directory for the current running process and its children. A program that is run in such a modified environment cannot name (and therefore normall ...

(originally used to test the V7 distribution during preparation), exece,

ioctl In computing, ioctl (an abbreviation of input/output control) is a system call for device-specific input/output operations and other operations which cannot be expressed by regular system calls. It takes a parameter specifying a request code; th ...

, lseek (previously only 24-bit offsets were available),

umask In computing, umask is a command (computing), command that determines the settings of a Mask (computing), mask that controls how file permissions are set for newly created files. It may also affect how the file permissions are changed explicitly. ...

, utime *New library calls: The new

stdio The C programming language provides many standard library functions for file input and output. These functions make up the bulk of the C standard library header . The functionality descends from a "portable I/O package" written by Mike Lesk at ...

routines,

malloc C dynamic memory allocation refers to performing manual memory management for dynamic memory allocation in the C programming language via a group of functions in the C standard library, namely , , , and . The C++ programming language includes ...

, getenv, popen/system *

Environment variable An environment variable is a dynamic-named value that can affect the way running processes will behave on a computer. They are part of the environment in which a process runs. For example, a running process can query the value of the TEMP envi ...

s *A maximum file size of just over one

gigabyte The gigabyte () is a multiple of the unit byte for digital information. The prefix ''giga'' means 109 in the International System of Units (SI). Therefore, one gigabyte is one billion bytes. The unit symbol for the gigabyte is GB. This defini ...

, through a system of indirect addressing

Multiplexed files

A feature that did not survive long was a second way (besides pipes) to do

inter-process communication In computer science, inter-process communication or interprocess communication (IPC) refers specifically to the mechanisms an operating system provides to allow the processes to manage shared data. Typically, applications can use IPC, categori ...

: multiplexed files. A process could create a special type of file with the mpx system call; other processes could then open this file to get a "channel", denoted by a

file descriptor In Unix and Unix-like computer operating systems, a file descriptor (FD, less frequently fildes) is a process-unique identifier (handle) for a file or other input/output resource, such as a pipe or network socket. File descriptors typically have ...

, which could be used to communicate with the process that created the multiplexed file. Mpx files were considered experimental, not enabled in the default kernel, and disappeared from later versions, which offered sockets (BSD) or CB UNIX's IPC facilities (System V) instead (although mpx files were still present in 4.1BSD).

References

External links

Unix Seventh Edition manual
(Bell Labs)
Browsable source code

PDP Unix Preservation Society
{{Unix-like Bell Labs Unices Berkeley Software Distribution Discontinued operating systems Free software operating systems 1979 software