Unix/Linux

What is the connection between these operating systems?

Among technical people and computer programmers, "Unix" describes a family of computer operating systems with common design elements, all patterned on (but not necessarily derivative works of) the ancestral Unix invented at Bell Labs in 1969. As SCO/Caldera observes in its complaint, Unix operating systems dominate serious computing, and have for more than twenty years. There have been hundreds of different Unixes in this sense, exhibiting variations analogous to dialects within a language. [...]

When we wish to be clear that this is the definition we are using, we will refer to "Unix-family" operating systems. [...]

The term "Unix" is sometimes also used (primarily by historians of computing) more strictly, to describe only those Unix-family operating systems which are derivative works of the original Bell Labs Unix. To avoid confusion, we shall call any operating system of this kind a "genetic Unix".

Legally, the term "Unix" has been since 1994 a trademark of The Open Group[2], a technical standards organization, and describes any operating system (whether genetic-Unix or not) that has been verified to conform to the published Unix standard. We will refer to an operating system of this kind as a "trademark Unix". The required attribution is "UNIX is a registered trademark of The Open Group". [3] However, The Open Group's strict construction of the term "Unix" is more honored in the breach than the observance. [...]

The Linux operating system is Unix-family and generally referred to as a Unix, but is neither a genetic Unix nor a trademark Unix. Linux was independently created by Linus Torvalds in 1991[4], and most versions have not been put through the rather expensive process required to verify conformance with The Open Group standards.