DaimlerChrysler has responded robustly to SCO's Linux lawsuit. SCO claimed Daimler had refused to provide it with a "certificate of compliance" over its long-term Unix contract. Daimler response? Tough.

The car manufacturer asked a Michigan court to dismiss the lawsuit because there was "no genuine issue of material fact" in it. Daimler says it has no obligation to provide SCO with any such certification, but that it had nevertheless sent it a letter about the situation.

"DaimlerChrysler has provided SCO with the only certification required under the licence demonstrating that DaimlerChrysler is not even using and has not used the licensed software for more than seven years," the response stated.

SCO's head Darl McBride admitted at a press conference in March that the real reason SCO was chasing Daimler was because of its contribution towards and continued work on Linux - the open-source OS that SCO appears to believe it has a property right over.

However, Daimler's filing has revealed that it has sent two letters with regard to the matter. One, written by DaimlerChrysler's senior manager of tech services Norman Powell, was addressed to Unix System Laboratories in North Carolina and certified that DaimlerChrysler is no longer using the software licensed under an 1990 agreement between Chrysler and Unix System Laboratories.

The second was written by DaimlerChrysler CIO Susan Unger and addressed to SCO's director of software licensing Bill Broderick and stated that SCO has no right to seek its certification and that its first letter "should cause SCO to dismiss its suit".

To follow the merry-go-round properly: Novell bought Unix System Laboratories from AT&T in 1993. Some of these rights were later transferred to SCO, and now SCO claims those rights are infringed in Linux. It has thus embarked on a legal crusade against - among others - IBM and Novell, in order to drag money out of them of them for their Linux offerings.

Everyone else begs to differ - including Novell which says it never gave SCO the copyright to the System V code at the centre of the argument in the first place. It hasn't helped SCO's case that it recently emerged Microsoft has been key in getting SCO the financial backing it needed to pursue its case so agressively in the courts. Microsoft is of course deeply worried about the undermining effect that Linux may have on Windows.

The company that provided the backing - BayStar - also asked for its $20 million back this month claiming breach of contract, but the real reason is thought to be BayStar concern that SCO is spreading itself too thin by taking on a different monster company every month.

DaimlerChrysler is one such behemoth. And it is treating SCO with amused disdain. "We were rather puzzled when we saw the lawsuit because we never had any agreement with SCO and never had any knowledge that SCO had assumed the rights to that agreement," said spokeswoman Mary Gauthier.

The car maker has asked the Court to "grant summary disposition in its favour and against SCO, and deny SCO its requested relief." SCO had been seeking damages for what it called "past violations of the DaimlerChrysler Software Agreement."

The fact that DaimlerChrysler has now produced the requested certification is unlikely to end SCO's lawsuit, said Bruce Perens, an open source advocate who has been following the case. "I do not expect SCO to willingly drop any lawsuit, nor do I expect them to willingly allow any lawsuit to complete," he said. "The whole idea is for SCO to have lawsuits in play and for them to deceive people like Baystar into believing that there's a chance of them succeeding," he said.

SCO declined to comment.