Two companies The SCO Group targeted with lawsuits earlier this year have fired back questioning the very foundation of SCO's allegations.
Car maker, DaimlerChrysler, and auto parts retailer, AutoZone, filed court documents last month responding to SCO's charges.
In a lawsuit filed in March, SCO accused DaimlerChrysler of violating a 14-year-old Unix licensing agreement by not providing "certification of compliance."
In court documents, DaimlerChrysler said it had provided SCO with appropriate certification and that it in fact was not and had not used the licensed software for more than seven years.
AutoZone responded to allegations that it was violating SCO copyrights by running Linux by arguing that questions regarding whether Linux indeed violated any SCO copyrights and whether SCO owned those copyrights to begin with must first be decided in several other pending lawsuits.
IBM, Red Hat and Novell are currently in legal battles with SCO over Unix copyrights.