SCO Group's case against Linux

SCO Group, also known as Caldera Systems, certainly thinks so. It sent vague letters last week to about 1,500 corporations, warning them that "Linux infringes on our Unix intellectual property and other rights," and predicting that end users of the OS could face "legal liability." The company has also sued IBM over the issue. Microsoft said this week that it will license rights to Unix from SCO. The software giant and foe of both Linux and IBM did not disclose details.

The $1 billion lawsuit that financially struggling SCO filed in March against IBM provides a glimpse of what claims the company might make if it takes legal action against Linux users or distributors:

• SCO says that IBM's decision to contribute elements of AIX, its own Unix-based operating system, to the open source community was unlawful because AIX "contains SCO's confidential and proprietary Unix operating system and, more importantly, the code that is essential for running mission critical applications," the complaint says.

• Without stating it outright, SCO implies that portions of the SCO OpenServer Shared Libraries have been incorporated into Linux. "The mathematical probability of a customer being able to re-create the SCO OpenServer Shared Libraries without unauthorized access to or use of the source code of the SCO OpenServer Shared Libraries is nil," SCO says.

• SCO alleges that IBM's Linux development efforts "misappropriated SCO's trade secrets" that Big Blue had acquired by licensing Unix from the SCO Group, which owns the intellectual property rights to the original Unix code created at AT&T's Unix Systems Laboratories. Additional confidential collaboration occurred, SCO alleges, when the two companies worked together on a plan called Project Monterey to build a new 64-bit Unix operating system for computers with Intel processors. When the onetime partners went their separate ways, in May 2001, IBM illegally "chose to use and appropriate for its own business the proprietary information obtained from SCO," SCO charges.

• SCO says IBM's decision to spend a billion dollars on Linux development was the single most important factor in transforming Linux from a hobbyist platform into one that businesses would embrace. That could not have happened "without the misappropriation of Unix code, methods or concepts to achieve such performance," SCO says. Other allegations include unfair competition, breach of contract and tortious interference with contract.

In its response to SCO, IBM has denied the allegations. SCO's lawsuit does not include any patent claims.

John Ferrell, an intellectual-property attorney with Carr and Ferrell in Palo Alto, Calif., said Monday that it would be difficult for SCO to prove that its code had leaked into the Linux operating system, which includes many utilities released under the GNU General Public License. "One of the difficulties of making a case for copyright infringement is that there has to be access (to the copyrighted code) and there has to be substantial similarity in the code," Ferrell said. "Assuming you can prove those two things, there is an inference that can be drawn that copying has occurred."

If SCO identifies the specific parts of the Linux code that it believes it owns, developers in the free software movement could replace it with their own work. Ferrell cautions, however, that such a tactic would still leave users open to the possibility of damages for activity that occurred in the past. "You can design the code out, and that certainly gets rid of an injunction as a viable remedy, because there will be nothing left to enjoin," Ferrell said. "However, there still is the issue of past damages that SCO would have the opportunity to seek redress for."

Because SCO's original complaint was filed in state court in Utah, it does not make any copyright claims. But IBM successfully moved the suit to federal court, which means SCO can amend its complaint to allege copyright infringements. Under federal law, a copyright owner may sue individuals or corporations for statutory damages of up to $150,000 for willful infringements, plus court costs and attorneys' fees.

But lawsuits of this type aren't easy to win. A 1999 book on open source by Marshall McKusick recounts what happened when AT&T sued Berkeley Software Design and the University of California at Berkeley for alleged Unix copyright infringements and theft of trade secrets. It ended in a settlement that required three of 18,000 files to be removed from the Berkeley (Networking Release 2) version of Unix.

A position paper from the Open Source Initiative, written by Eric Raymond and Rob Landley, says that in the current SCO v. IBM case, "a judgment in favor of SCO could do serious damage to the open-source community. SCO's implication of wider claims could turn Linux into an intellectual-property minefield, with potential users and allies perpetually wary of being mugged by previously unasserted IP claims, and ever-more-outlandish theories of entitlement being propounded by parties with only the most tenuous relationship to anyone who ever wrote actual program code."

In an interview on May 1, SCO Chief Executive Darl McBride would not give details about any alleged misappropriation of SCO source code but said: "We're finding...cases where there is line-by-line code in the Linux kernel that is matching up to our UnixWare code...We're finding code that looks likes it's been obfuscated to make it look like it wasn't UnixWare code--but it was."