The suit, filed in a Texas state court by intellectual property firm IP Innovation LLC, claims that the Linux vendors are infringing on its U.S. Patent No. 5,072,412. The patent, originally issued Dec. 10, 1991, describes a "User Interface with Multiple Workspaces for Sharing Display System Objects."
"Red Hat's and Novell's infringement, contributory infringement and inducement to infringe has injured plaintiffs and plaintiffs are entitled to recover damages adequate to compensate them for such infringement but in no event less than a reasonable royalty," IP Innovation LLC's said in its filing.
Novell and Red Hat said they were reviewing their options.
"Obviously, we'll defend our interests," Novell spokesman Bruce Lowry said. "But it's too early at this stage to talk about specifics on this case, including whether there might be a role for a joint approach with Red Hat."
A Red Hat spokesperson likewise told InternetNews.com that the company is assessing the suit.
Both companies have indemnification programs in place for their enterprise users, which are designed to protect customers from the threat of patent-related litigation. Nevertheless, the lawsuit represents the first time that Linux has been tested in court over patent infringement.
Originally granted to Xerox in 1991 and since sold to IP Innovation, the patent in question includes references that date back to 1984, when IBM received U.S. Patent No. 4484302. That patent protected a "Single screen display system with multiple virtual display having prioritized service programs and dedicated memory stacks."
IBM spokespeople were not immediately available for comment.
The filing was first reported earlier this week in the Patent Troll Tracker blog. The site also claims that IP Innovation is a subsidiary of Acacia, a firm well known in patent circles for its business of buying patents -- such as the one-time Xerox patent now at the heart of this week's filing -- then aggressively asserting them.
According to Patent Troll Tracker, Acacia has sued hundreds of defendants in 213 different patent lawsuits brought by 36 different Acacia subsidiaries.
Acacia spokespeople did not return requests for comment by press time.
The IP Innovation lawsuit comes hot on the heels of Microsoft CEO Steve Ballmer's revival of allegations that Linux users need to pay it for its use of Microsoft intellectual property.
Though Microsoft itself apparently is uninvolved with IP Innovation or Acacia, there is an indirect connection -- on Oct. 1st, Acacia announced in a press release that Brad Brunell, Microsoft's former general manager of intellectual property licensing, joined the management team at Acacia.
This article was first published on InternetNews.com.