Re: Obligatory Linux angle
> the entity holding the copyright for Unix would be able to shut Linux down. It is not entirely clear who that is at the moment - either Micro Focus International, or our old friends SCO.
You are quite wrong about that on many levels.
The SCO versus Novell case found that Novell did not pass any copyrights to SCO.
Whether Novell holds _any_ protectable copyrights in Unix has not been tested. Some versions of Unix were never registered when this was a requirement. Some versions of Unix were released to the public domain (v32). Much of the Unix code was developed by third parties who may, or may not, retain copyright over their own code, many of whom are probably not contactable.
And mainly: there is no Unix code in Linux.
As for the POSIX API, this is explicity allowed to be used, so no action there is possible.