UNIX
Pronounced yoo-niks, a popular multi-user, multitasking operating system developed at Bell Labs in the early 1970s. Created by just a handful of programmers, UNIX was designed to be a small, flexible system used exclusively by programmers. Although it has matured considerably over the years, UNIX still betrays its origins by its cryptic command names and its general lack of user-friendliness. This is changing, however, with graphical user interfaces such as MOTIF.
UNIX was one of the first operating systems to be written in a high-level programming language, namely C. This meant that it could installed on virtually any computer for which a C compiler existed. This natural portability combined with its low price made it a popular choice among universities. (It was inexpensive because antitrust regulations prohibited Bell Labs from marketing it as a full-scale product.)
Bell Labs distributed the operating system in its source language form, so anyone who obtained a copy could modify and customize it for his own purposes. By the end of the 1970s, dozens of different versions of UNIX were running at various sites.
After its breakup in 1982, AT&T began to market UNIX in earnest. It also began the long and difficult process of defining a standard version of UNIX. To date, there are two main dialects of UNIX; one produced by AT&T known as System V and one developed at Berkeley University and known as BSD4.x, x being a number from 1 to 3.
Due to its portability, flexibility, and power, UNIX has become the leading operating system for workstations. Historically, it has been less popular in the personal computer market, but the emergence of a new version called Linux is revitalizing UNIX across all platforms.