UNIX System III was a version of the Unix

Unix

Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...

 operating system released by AT&T

AT&T

AT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...

's Unix Support Group (USG). It was first released outside of Bell Labs

Bell Labs

Bell Laboratories is the research and development subsidiary of the French-owned Alcatel-Lucent and previously of the American Telephone & Telegraph Company , half-owned through its Western Electric manufacturing subsidiary.Bell Laboratories operates its...

 in 1982. UNIX System III was a mix of various AT&T Unixes: PWB/UNIX

PWB/UNIX

The Programmer's Workbench was an early version of the Unix operating system created in the Bell Labs Computer Science Research Group of AT&T....

 2.0, CB UNIX

CB Unix

Columbus UNIX was, according to Marc Rochkind, a variant of the UNIX operating system internal to Bell Labs. It was developed at the Columbus, Ohio branch and was little-known outside the company...

 3.0, UNIX/TS 3.0.1 and UNIX/32V

UNIX/32V

UNIX/32V was an early version of the Unix operating system from Bell Laboratories, released in June 1979. 32V was a direct port of the PDP-11 Seventh Edition Unix to the DEC VAX architecture....

. System III supported the DEC

Digital Equipment Corporation

Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...

 PDP-11

PDP-11

The PDP-11 was a series of 16-bit minicomputers sold by Digital Equipment Corporation from 1970 into the 1990s, one of a succession of products in the PDP series. The PDP-11 replaced the PDP-8 in many real-time applications, although both product lines lived in parallel for more than 10 years...

 and VAX

VAX

VAX was an instruction set architecture developed by Digital Equipment Corporation in the mid-1970s. A 32-bit complex instruction set computer ISA, it was designed to extend or replace DEC's various Programmed Data Processor ISAs...

 computers.

The system was apparently called System III because it was considered the outside release of UNIX/TS 3.0.1 and CB UNIX 3 which were internally supported Bell Labs Unices. Its documentation calls it UNIX Edition 3.0 and there were no Unix versions called System I or System II. There was no official release of UNIX/TS 4.0 (which would have been System IV) either, so System III was succeeded by System V

UNIX System V

Unix System V, commonly abbreviated SysV , is one of the first commercial versions of the Unix operating system. It was originally developed by American Telephone & Telegraph and first released in 1983. Four major versions of System V were released, termed Releases 1, 2, 3 and 4...

, based on UNIX/TS 5.0.

System III introduced new features such as named pipes, the uname

Uname

uname is a software program in Unix and Unix-like computer operating systems that prints the name, version and other details about the current machine and the operating system running on it...

 system call and command, and the run queue

Run queue

In modern computers many processes run at once. Active processes are placed in an array called a run queue, or runqueue. The run queue may contain priority values for each process, which will be used by the scheduler to determine which process to run next...

. It also combined various improvements to Version 7 by outside organizations. However, it did not include notable improvements made in BSD

Berkeley Software Distribution

Berkeley Software Distribution is a Unix operating system derivative developed and distributed by the Computer Systems Research Group of the University of California, Berkeley, from 1977 to 1995...

 such as the C shell

C shell

The C shell is a Unix shell that was created by Bill Joy while a graduate student at University of California, Berkeley in the late 1970s. It has been distributed widely, beginning with the 2BSD release of the BSD Unix system that Joy began distributing in 1978...

 (csh) and screen editing.

Third-party variants of System III include (early versions of) HP-UX

HP-UX

HP-UX is Hewlett-Packard's proprietary implementation of the Unix operating system, based on UNIX System V and first released in 1984...

, IRIX

IRIX

IRIX is a computer operating system developed by Silicon Graphics, Inc. to run natively on their 32- and 64-bit MIPS architecture workstations and servers. It was based on UNIX System V with BSD extensions. IRIX was the first operating system to include the XFS file system.The last major version...

, IS/3

INTERACTIVE Systems Corporation

INTERACTIVE Systems Corporation was a US-based software company and the first vendor of the Unix operating system outside AT&T, operating from Santa Monica, CA....

, PC-UX

PC-UX

PC-UX was a NEC port of UNIX System III for their APC III and PC-9801 personal computer. It had extensive graphics capability. PC-UX and MS-DOS could reside on the same hard drive. It also had file transfer utilities that allowed files between PC-UX and MS-DOS. There was the PC-UX Softcard which...

, PNX

PERQ

The PERQ, also referred to as the Three Rivers PERQ or ICL PERQ, was a pioneering workstation computer produced in the early 1980s....

, SINIX

SINIX

SINIX was a variant of the Unix operating system from Siemens Nixdorf Informationssysteme. Supersedes SIRM OS and Pyramid Technology's DC/OSx. Its last release under the SINIX name was version 5.43 in 1995...

, Venix

Venix

Venix was a version of the Unix operating system developed by VenturCom.Venix 2.0, based on System III, ran on the DEC PRO-350 microcomputer , the DEC Rainbow 100 as well as PCs . It was released in 1984...

 and Xenix

Xenix

Xenix is a version of the Unix operating system, licensed to Microsoft from AT&T in the late 1970s. The Santa Cruz Operation later acquired exclusive rights to the software, and eventually superseded it with SCO UNIX ....

.

External links

• 20 Years Ago in UNIX by Peter Salus
• [ftp://pdp11.org.ru/pub/unix-archive/PDP-11/Distributions/usdl/SysIII/ System III source code]