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<br>After three decades of use, the UNIX computer operating system from Bell Labs is still regarded as one of the most powerful, versatile, and flexible operating systems (OS) in the computer world. Its popularity is due to many factors, including its ability to run a wide variety of machines, from micros to supercomputers, and its portability -- all of which led to its adoption by many manufacturers.
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<br>The UNIX operating system was designed to let a number of programmers access the computer at the same time and share its resources. While initially meant for medium-sized computers, the system was soon moved to larger, more powerful mainframe computers. As personal computers grew in popularity, versions of UNIX found their way into these boxes, and a number of companies produce UNIX-based machines for the scientific and programming communities.
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<br>A major contribution of the UNIX system was its portability, permitting it to move from one brand of computer to another with a minimum of code changes. At a time when different computer lines of the same vendor didn 't talk to each other -- yet alone machines of multiple vendors -- that meant a great savings in both hardware and software upgrades. It also meant that the operating system could be upgraded without having all the customer 's data inputted again. And new versions of UNIX were backward compatible with older