14 August 2003 SCO Group, the Unix software vendor that claims that open source operating system Linux infringes its intellectual property, will argue in court that the general public licence (GPL) under which Linux is distributed is invalid.

SCO lead attorney Mark Heise of law firm Boies, Schiller &Flexner says that the GPL “is pre-empted by [US federal] copyright law” because it allows unlimited copying and modification, whereas US federal copyright law only allows software buyers to make a single backup copy.

The claim was made in the Wall Street Journal and drew a cautious response from open source software advocates. Eric Raymond, free software developer and author of The Cathedral and the Bazaar, expressed concern that a judge could invalidate the GPL on those grounds, although he felt it was unlikely.

The case is being heard by a district court in Salt Lake City in SCO Group’s home state of Utah and Raymond has already taken the precaution of developing an alternative free software licence. The new licence is endorsed by Linux creator Linus Torvalds, who will switch Linux to it, if necessary.

The GPL has helped underpin the fast growth of open source software by guaranteeing that free software developers do not have their work ripped-off by commercial organisations.

The GPL has meant that Linux distributors such as Red Hat and SuSE have to make their distributions freely available — sometimes even giving them away free on the covers of computer magazines — and instead have to build a business model around service and support, rather than packaged software sales.

SCO’s attack on the GPL mirrors that of software giant Microsoft, which has described it as “a cancer”. A Microsoft spokesman told the WSJ that a “the industry would benefit” from a court ruling on the GPL.

SCO will also have to explain to the court why it distributes and continues to make available for download from its web site its own version of Linux.