SCO Group chief executive Darl McBride has warned that his company may exercise its rights to audit IBM's AIX customers.

SCO has terminated IBM's right to sell its AIX operating system and is seeking $3bn in damages.

It has also filed a permanent injunction requiring IBM to "cease and desist all use and distribution of AIX", and to return all copies of Unix source code to SCO.

The lawsuit claims that IBM broke its contract with SCO by allowing parts of SCO's Unix V source code, licensed to IBM for use in AIX, to be used in the rival Linux operating system kernel.

In an exclusive interview, McBride told vnunet.com that SCO was about to embark on the discovery process of its legal case, when it looks for material related to the case.

"As we move into discovery, this will be very nice for us because now we get to go in and talk to all their people, their customers. We get to really shake things up and get in to find out what really is going on over there," he said.

McBride claimed that SCO has the right to audit IBM's customers. "We have other rights under the contract we are looking at. For example, we can audit IBM customers. SCO has audit rights on its customers," he said.

"The reality is that we are going into discovery right now and that might be the vehicle to be able to investigate what we need there anyway."

McBride indicated that SCO's case against IBM is very strong. "The people that have looked at this, both our legal teams as well as independent people coming from the outside, say: 'These contracts are bullet-proof. This is a very strong contract right you have,'" he said.

IBM has refused to comment further on any of the issues ahead of the lawsuit.

But in a statement last week, the company said: "IBM's Unix licence is irrevocable, perpetual and fully paid up. It cannot be terminated. IBM will defend itself vigorously."

IBM said that it will continue to ship, support and develop AIX and would, as always, stand behind its customers.