RESEARCH TRIANGLE–IBM Corp. (NYSE:IBM) filed a countersuit against SCO Group Inc. (Nasdaq:SCOX) claiming that SCO violated the general public license agreement under which it accepted and distributed the Linux open source computer operating system.

SCO sued IBM for billions, claiming code from its Unix software is illegally embedded in the free Linux operating system. SCO also threatened 1,500 distributors of the Linux software, including Triangle-based Red Hat, with legal action.

IBM, which filed the countersuit in SCO’s home state of Utah, says SCO
Improperly revoked IBM’s Unix operating system license and infringed on four IBM patents relating to software applications.

CBS Marketwatch reports that Bob Samson, vice president of IBM’s systems group sales force, told sales representatives, “We see no merit in their claims and no supporting facts. SCO will continue to look for ways to create fear, uncertainty and doubt.”

SCO followed IBM’s countersuit announcement with a statement that called it “an effort to distract attention from its flawed Linux business model.”

IBM seeks immediate compensatory and punitive damages, but amounts sought were not disclosed.

IBM employs 13,500 people in the Triangle.

Monday, Red Hat filed a complaint in a Delaware Court asking it to stop SCO from making claims disruptive to its business.

Linux supporters rallied at the Linux World Expo in San Francisco this week, where Red Hat Chief Executive Officer Matthew Szulik was cheered when he announced his company’s response to SCO.

SCO’s shares fell 97 cents, or, 8 percent, Thursday, to close at $11.03, while IBM climbed 94 cents finishing the day at $80.69.