The falseness of SCO's allegations is partly cloaked by the fact that their complaint uses the term “Unix” three different ways.
Among technical people and computer programmers, “Unix” describes a family of 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 observes in its complaint, Unix operating systems dominate serious computing, and have for twenty years. When we wish to be clear that this is the definition we are using, we will refer to “Unix-patterned” operating systems. This general sense was common usage long before SCO's acquisition of the historical Unix codebase in 1995; AT&T's lawyers strove against it in vain as far back as the early 1980s.
Read Full Essay re. SCO's pathetic claims at <http://www.opensource.org/sco-vs-ibm.html#id2790793> (as I have said many times in the past, if they had their act together there wouldn't have been a Linux. Most early Linux users were disgruntled SCO developers and users).