Unix (officially trademarked as UNIX) is a multi-tasking, multi-user computer operating system that exists in many variants. The original Unix was developed at AT&T’s Bell Labs research center by Ken Thompson, Dennis Ritchie, and others. From the power user’s or programmer’s perspective, Unix systems are characterized by a modular design that is sometimes called the Unix philosophy, meaning the OS provides a set of simple tools that each perform a limited, well-defined function, with a unified file-system as the main means of communication and a shell scripting and command language to combine the tools to perform complex work-flows.
During the late 1970s and 1980s, Unix developed into a standard operating system for academia. AT&T tried to commercialize it by licensing the OS to third-party vendors, leading to a variety of both academic (e.g., BSD) and commercial variants of Unix (such as Xenix) and eventually to the “Unix wars” between groups of vendors. AT&T finally sold its rights in Unix to Novell in the early 1990s. To view the time history of versions click here. There is a long history dating back to 1969.
The Open Group, an industry standards consortium, now owns the UNIX trademark and allows its use for certified operating systems compliant with its standard, the Single UNIX Specification. Other operating systems that emulate Unix to some extent may be called Unix-like, although the Open Group disapproves of this term. The term Unix is also often used informally to denote any operating system that closely resembles the trademarked system. The most common version of Unix (bearing certification) is Apple’s OS X, while Linux is the most popular non-certified workalike. The current definition of Unix is given here and who currently own the UNIX trademark.
This work was funded by a NERC Postgraduate and Professional Skills Development Award.
Associate Professor in Atmospheric Physics at the University of Leeds with over twenty years of programming experience in a research environment and about a decade of training experience.