Continuing its war of words against the Linux community, The SCO Group Wednesday accused free software advocates of threatening the intellectual property protections provided by U.S. and European law.

"There is a group of software developers in the United States, and other parts of the world, that do not believe in the approach to copyright protection mandated by Congress," SCO CEO Darl McBride wrote in an open letter posted on SCO's Web site Wednesday.

The letter argues that Linux's GPL (GNU General Public License) software license is "exactly opposite in its effect from the 'copyright' laws adopted by the U.S. Congress and the European Union."

It accuses the creators of the GPL, the Free Software Foundation (FSF) and Red Hat of seeking to eliminate the profit motive from software development, and argues that the profit motive "underpins the constitutionality of the (U.S.) Copyright Act."

The letter was written in response to a position paper authored by FSF General Council Eben Moglen and published Nov. 24 on the Open Source Development Lab (OSDL) Web site, a SCO spokesman said.

Linux backers blasted the letter, pointing out that the GPL itself requires copyright protection in order to be enforceable, and accusing SCO itself being a copyright violator by distributing Linux under terms contrary to the GPL.

McBride's argument has its "fundamental facts wrong," said Linux creator Linus Torvalds.

"I'm a big believer in copyrights," Torvalds wrote in an e-mail interview. "Of all the intellectual property (laws), copyright ... is the only one that is expressly designed so that individual people can (and do) get them without having scads of lawyers on their side."

"If Darl McBride was in charge, he'd probably make marriage unconstitutional too, since clearly it de-emphasizes the commercial nature of normal human interaction, and probably is a major impediment to the commercial growth of prostitution," he wrote.

McBride's company sued IBM in March, claiming that IBM's Linux contributions had violated SCO's intellectual property. Since then SCO has escalated its rhetoric, accusing Linux developers of copyright violations and of threatening to destroy the software industry itself.

SCO has been reluctant to provide proof of its claims, and in August the Lindon, Utah, company was sued by Red Hat, which maintains that SCO's allegations are unfounded and are causing harm to Red Hat's business.

The IDG News Service is a Network World affiliate.