Blogs (here and here and here) are pointing out the SCO has lost its rights to sue IBM over stolen code in AIX and Linux. It seems the rights that SCO said it had to sue, actually belonged to Novell, who licenses its software to SCO. (Novell would have to do the suing).
Dvorak has a nice timeline (here).
Here is the history of UNIX code, which started at Bell Labs and ended up at Novell.