(IDG News Service) — Didn't do it. That's the clear message IBM Corp. has sent with its reply to The SCO Group's $1 billion lawsuit in which it accuses Big Blue of illegally trying to damage Unix to build up Linux.

IBM categorically declares that it "has not engaged in any wrongdoing" and that, contrary to SCO's allegations, it has not misappropriated any trade secrets, nor engaged in unfair competition, nor interfered with SCO's contracts nor breached any contractual obligations to SCO.

IBM filed its response on Thursday in the U.S. District Court for the District of Utah to SCO's lawsuit from early March. [See: Analysis: SCO's case against IBM stands on shaky ground]

SCO is seeking damages of at least $1 billion for what it says are IBM's efforts to improperly destroy the economic value of Unix, an operating system SCO owns and licenses to other companies, to bolster IBM's efforts around the Linux operating system.

Linux's kernel is developed by a team of volunteers worldwide led by its creator Linus Torvalds. This method of developing software is known as open source. The Linux kernel is freely available and its different versions developed commercially by vendors such as Red Hat Inc. and SuSE Linux AG have gained wide acceptance as an option to desktop and server operating systems such as Microsoft Corp.'s Windows and Unix.

IBM in particular has made huge investments on Linux, to make its hardware and software compatible with it.

In its 18-page response, IBM also strikes back at SCO, accusing it of "improperly seeking to assert proprietary rights over important, widely used technology and impeding the use of that technology by the open source community."

IBM also concedes very little to SCO, describing most of the lawsuit's allegations and statements as untrue or withholding comment due to insufficient information. It appears the extent of the disagreements between the two sides could lead to a long and difficult legal process.

Particularly interesting are IBM's positions regarding SCO's claims of ownership over Unix. For example, IBM claims lack of information to assert as true, among other things:

• That Unix was originally developed by AT&T Corp.'s Bell Laboratories;
• That AT&T used to license Unix to other companies;
• That AT&T licensed Unix to IBM;
• That all commercial Unix flavors in use today are based on SCO's System V Unix technology;
• That SCO owns the rights in and to all underlying, original Unix software code developed by AT&T Bell Laboratories;
• That SCO is the authorized successor in interest to and the owner of all the contractual rights arising from the AT&T Unix agreements

IBM also outright denies that its AIX flavor of Unix is a modification of SCO's licensed Unix.

IBM also contests that the Utah court is the proper venue for the lawsuit, although it doesn't say which venue would be more appropriate.