Red Hat’s Linux system and Novell’s SuSe Linux Enterprise Desktop and Enterprise Server allegedly infringe on three patents relating to user interfaces within multiple windows, according to the suit filed by two US patent houses.

Enterprise users of these products are protected by indemnification clauses in their contracts that should shield them from intellectual-property litigation.

Novell spokesperson Bruce Lowry said the company was assessing the lawsuit. Obviously, we’ll defend our interests, he 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.

The suit jointly filed by Texas-based IP Innovation and Nevada-based Technology Licensing Corp. They are seeking unspecified damages and royalty fees.

According to the Patent Troll Tracker blog, IP Innovation is a subsidiary of Acacia, which has been aggressively enforcing streaming media patents against small webmasters and others. Acacia has been accused of being a patent troll, which is a company that does not make or sell any products but files aggressive patent lawsuits against those that do.

Coincidentally, Novell in May joined the Electronic Frontier Foundation’s Patent Busting initiative that aims to invalidate bogus US patents by seeking out evidence of prior art — earlier inventions that preclude patentability. The program was launched in response to companies like Acacia Research, which has filed 213 different patent lawsuits via 36 separate subsidiaries, according to Patent Troll Tracker.

Ironically, in late August Acacia’s Disc Link subsidiary announced a license deal with Novell covering its patents related to portable storage devices with links.

The three US patents in the Linux suit are entitled User Interface with Multiple Workspaces for Sharing Display System Objects. They were issued in late-1991, early-1995 and mid-1996. The first was initially granted to Xerox and then sold to IP Innovation.

Our View

Given the current state patent litigation in the US, the lawsuit against the Linux vendors is hardly surprising. It is curious, however, that other open-source vendors are not named, such as IBM.

There has been much speculation that Microsoft is somehow behind this lawsuit, in light of CEO Steve Ballmer’s recent comments that Red Hat infringes on Microsoft IP. People who use Red Hat, at least with respect to our intellectual property, in a sense have an obligation to compensate use, were Ballmer’s words during an online-services brief in the UK. But there is no proof or obvious motivation for Microsoft to drag Red Hat into the courts.