[1969]] on the computer architecture of the PDP-7 and PDP-9's DEC. Its principal authors were Ken Thompson and Dennis Ritchie. The initial goal of creating a new operating system has been achieved and the authors began work on a second version of the PDP-11. This version was launched in 1971. At that time, appeared in Unix Programmer's Manual, which was de facto description of the then Unix. The second edition of Unix came in 1972, which introduced the concept of stream between processes. Minicomputers PDP-11 gained great popularity, and with them also Unix. Therefore, shortly written a third version of the operating system Unix.
The authors opted to write the system in assembler and moved all the code developed by Dennis Ritchie higher level language C, which resulted in portability system.
In 1974, Ritchie and Thompson, published an article about Unix in the Communications of the Association for Computing Machinery. It describes the structure and its operation. In 1978 he issued a special edition of the Bell System Technical Journal on Unix
1975 - UNIX Sixth Edition of - different version Sixth - distributed free of charge to universities for academic use. This has contributed to the rapid development of the system, the emergence of outside AT & T extension and software. The legend of this period became written by a professor at the University of New South Wales in Australia, by John Lions so. Lions book contains the complete code V.6, together with a commentary line after line.
Unix quickly appear to be settled at the University of California, Berkeley, where he was transferred to replace the PDP-11 architecture VAX. The first version released on mini computers, VAX was available as part of the Third Berkeley Software Distribution, or 3bsd.
In 1978 he released version 7 (Version 7) - was the first widely available, although AT & T does not provide support and service. Its range of features and programs were until the appearance of the IEEE and POSIX main base unifying emerging varieties of Unix.
One of the most important events in the early history of Unix was the project DARPA's adoption of a single operating system on all computers ARPANET. DARPA decided that this system will be version of Berkeley Unix. Under the first contract, which lasted from 1981-1982, was a system 4BSD and 4.1BSD. Success led to another two-year contract, which the fruit was 4.2BSD, which is the first operating system includes support for TCP / IP.

At the start of the 80s, AT & T decided to commercialize Unix. In 1980, the license to develop the code was sold to Santa Cruz Operations, who on behalf of Microsoft, was to prepare Xenix, its version of Unix. In 1983 he released the first commercial version of Unix from AT & T System V
Along with the commercialization of the AT & T no longer share the source code of the system outside the licensed commercial. This has led to protests among many engineers, university (UCB, MIT), who so far have written their own extensions of the system and participated in its development (vide: BSD). Blockade imposed on the code has become a cause of that on the basis of community members and independent creators of Unix free software movement. Founded in 1983 by Richard Stallman of MIT Free Software Foundation's objective is to develop a free Unix-like system with no code from AT & T.
Within the 80s created a lot of commercial versions of the system, the ambition of most IT firms has become a possession of their own varieties of Unix. Most of these projects was based on the code of the AT & T (SCO Xenix, SGI IRIX, DEC Ultrix et al.), Others have developed, based on freely available code of the BSD (SunOS, NEXTSTEP) or other projects, academics, for example, Mach (NEXTSTEP), some tied features the two branches or has evolved from one to the other (respectively IBM AIX and HP-UX). At that time, the University of Berkeley in the studios of CSRG constantly developed BSD.

Fragmentation of the different editions of isolation and development teams quickly led to problems with compatibility of different varieties, which resulted in efforts to standardize practices, views and functions. Demand is trying to meet a consortium of X / Open Company, which carries out the newly created concept of open systems.
In 1988 Sun and AT & T initiated a relationship that resulted in the first creation of a consortium of Unix International and the standard of SVR4, which combined the advantages of SysV or BSD - then based on it formed a new Unix Sun's Solaris (1991) and subsequent versions of the SCO, m . al. Xeniksa. Competing against duumwiratu producers formed the Open Software Foundation (OSF), under the auspices of which appeared with a time of ecumenical OSF / 1, strongly based on BSD. In 1988 he published the specification of POSIX.1 - forms the basis of what is called Unix.

Soon the early 90's warring factions facing based on the Internet rapid development of free Unix-type systems. In 1991, Linus Torvalds zaanonsował work on a kernel called Linux, which in combination with the tools of GNU FSF created a complete Unix-like operating system. AT & T and then Novell, which bought (22 December 1992) the rights to Unix, tried using the trial (1992-1994) to stop the development of systems written based on the constant a free code from CSRG Berkeley. Action stopped the development branch BSD, leading indirectly to the withdrawal of CSRG with further work on the code and the abandonment built on the open project 386BSD. However, for 1993, is emerging based on the latest release BSD4.4 and abandoned code 386BSD two new, free projects, FreeBSD and NetBSD. (More: History of BSD)
Novell has failed to combine two successful projects, their network services and Unix. In 1993 he appeared in the latest version of SysV, known as SVR4.2MP, before the company gave the right to allocate the brand Unix and regulating the Single UNIX Specification (SUS), the organization of X / Open, which two years later began a program of standardization, UNIX, 95 In the same year, Novell has decided to sell the code UnixWare - exact name sold System V - for the SCO and the old Bell Labs, Hewlett-Packardowi.
In 1996, a combination of OSF and X / Open formed the Open Group, which grants the right to use the name Unix for computer systems and takes care of the SUS.
In 1997 he released a second version of SUS - the first publicly available (introduced 64-bitowość, threads), and 2001 thirds integrating the POSIX extensions industry.
The turn of millennia and the 30th anniversary of Unix is a rapid development of content systems and displacement by non-commercial versions of the applications niche. Many manufacturers and sellers of Unix introduced to his offer of service and their own variety Linux or included in a development based on these technologies (BSDI, HP, IBM, SCO, Sun, Yahoo).