UNIX is a family of computer operating systems derived from an operating system developed by AT&T in the 1970s.
UNIX, written in all-caps, is the trademarked brand name of an operating system developed at Bell Labs by AT&T in the 1970s. Written without the caps, Unix is the term used to refer to all of the operating systems derived from the original UNIX kernel.
The original UNIX operating system, intended for use within the Bell System, was licensed to a number of vendors, including Microsoft, IBM, and Sun Microsystems, and finally sold outright to Novell in the 1990s. While the original operating system was passed to Novell, the UNIX trademark is owned by The Open Group, which allows the name to be used for any operating system that is certified compliant with the Single UNIX Specification.
Unix-derived operating systems power a large number of workstations, mobile devices, and web servers. The most popular Unix-derived operating system is Apple's OS X, which powers all Apple desktop computers, laptop computers, tablets, and smartphones. Another popular Unix operating system, Solaris by Oracle, bills itself as “the worlds most advanced enterprise operating system”. Variants of Linux, an open-source Unix clone, are the most popular operating system for public web servers.
Frequently Asked Questions
Is Linux based on Unix?
Linux is often referred to as a Unix clone or as being Unix-like. What this means is that Linux was developed to operate much in the same way as Unix. However, Linux does not have the right to use the Unix trademark, has never been certified compliant with the Single UNIX Specification, and, therefore, cannot legally claim any official relationship with the original UNIX operating system. However, it is worth noting that one of the original developers of UNIX, Dennis Ritchie, considers Linux to be a Unix derivative and a continuation of the ideas that inspired the development of UNIX. While Linux may not be an official UNIX-based operating system, it is closer to the original philosophy of the UNIX development team than many official UNIX-based systems.
What is the “Unix philosophy”?
Ken Thompson, one of the original developers of UNIX, set out the Unix philosophy as a philosophical approach for the development of software. The philosophy has been expressed in different ways by a variety of developers familiar with Thompson and his philosophy for software development. It was once summarized by Doug McIlroy as follows: “Write programs that do one thing and do it well. Write programs to work together. Write programs to handle text streams, because that is a universal interface.”
Where can I get a copy of UNIX?
While you can't get a copy of the original operating system developed by AT&T, you can get a taste of the UNIX operating system by installing a free UNIX-based operating system. One of the most popular, best-documented, and easiest to get started with is Free BSD. The software is available as a free download, and there's an extensive handbook to help you get started. If you're new to UNIX and Free BSD, take the time to review the free tutorial available from Free BSD before you do anything else.