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The system is a Unix operating system multiuser, multitasking, which means that it allows a single or multiple computers to run multiple programs by one or more users. It has one or more command interpreters (shell) and a large number of commands and many utilities (assemblers, compilers for many languages, word processing, email, ...). Moreover, it has a great portability, which means it is possible to implement a Unix system on virtually all hardware platforms.

Nowadays Unix systems are very much present in the professionals and academics with their stability, their high level of safety and compliance with major standards, particularly in terms of network.

The history of UNIX systems

The first "Unix" system has been developed by Ken Thompson in the Bell Labs AT & T in Murray Hill, New Jersey in the United States from 1965. The purpose of Ken Thompson was to develop an operating system simple interactive, called Multics (Multiplexed Information and Computing System) in order to turn a game he had created (space travel, a simulation of the solar system) .

A consortium consisting of MIT (Massassuchetts Institute of Technology), General Electric Co. And Bell Lab formed itself around and Multics.

In April 1969 laboratories AT & T decided to use the system GECOS (General Electric Comprehensive Operating System) in place of Multics. But Ken Thompson and Dennis Ritchie, who joined the team eûrent need to run the game space travel on a smaller machine (a DEC PDP-7, Programmed Data Processor with only 4K of memory to run programs by users), c That is why it réécrirent the system to create a scaled-down version of Multics called UNICS (UNiplexed Information and Computing Service), quickly entered into Unix.

The date of 1 January 1970 is considered as the date of birth of the Unix system, which explains why all system clocks of Unix operating systems start from that time.

Along with these activities, D. Ritchie greatly contributed to the definition of the C language (since it is regarded as one of its creators with BWKernighan), and the whole system was completely rewritten in C language in 1973 and baptized Unix Time - Sharing System (TSS).
When the system switched to version 7 in 1979, the evolution accompanied by many changes, such as:

The abolition of clamping linked to the size of the files,
Improved portability of the system (operating on many hardware platforms)
The addition of many utilities.
A decree dating back to 1956 prevented the company ATT, which depended Bell Labs, market anything other than telephone or telegraph equipment, which is why the decision was taken in 1973 to distribute UNIX sources in universities for educational purposes.

Since late 1977 researchers from the University of California redéveloppèrent a version of Unix from sources provided by AT & T to run the system on their VAX platforms and named for Berkeley BSD Software Development.

Thus two branches of development of sources were born:

The branch of AT & T would become of System V UNIX System Labs (USL)
BSD (Berkeley Software Development) developed by the University of California
In 1977 AT & T mit sources UNIX available to other companies, so that a large number of UNIX-like system was developed:

AIX, Unix-based commercial System V developed in February 1990 by IBM
Sun Solaris, Unix-based commercial System V and BSD developed by Sun Microsystems
HP-UX, Unix-based commercial BSD developed from 1986 by Hewlett Packard
Ultrix, commercial Unix developed by DEC
IRIX, commercial Unix developed by IMS
Unixware, commercial Unix developed by Novell
SCO Unix, Unix-based commercial System V developed in 1979 by Santa Cruz Operations and Hewlett Packard
Tru64 UNIX, Unix commercial developed by Compaq
In 1983 AT & T had the right to sell its Unix, which marked the emergence of UNIX System V, the commercial version of its Unix system.

In 1985 a Dutch professor named Andrew Tannenbaum, developed a minimal operating system called Minix to teach programming system for its students.
In 1991 a student from Finland, Linus Torvalds, decided to design, modeled after Minix, an operating system capable of operating on the type architectures 386.
He named this operating system "Linux" and posted the following message on the comp.os.minix newsgroup:


Nowadays Unix systems are very much present in the professionals and academics with their stability, their high level of safety and compliance with major standards, particularly in terms of network.