The current multiplicity of open source licences creates a "clear and present danger" to the open source community, according to commercial vendors including Computer Associates, HP and Novell.

The firms have begun pressing the Open Source Initiative (OSI) to reduce the large number of approved licences to just three.

The OSI is in charge of labelling licences as officially open source, based on compliance with a predefined set of criteria. The OSI website currently lists 58 official open source licences.

"Approving licences simply based on the compliance of the specification, rather than on the basis of the ability to further open source business models, represents a clear and present danger to the very core of these open source models," said Martin Fink, HP's vice president of Linux, in a keynote at LinuxWorld in Boston. "If this is the path the OSI continues to choose, it is picking a path towards irrelevance."

HP is going through the Open Source Development Labs to increase the pressure on OSI.

Fink is joined by John Swainson, chief executive at Computer Associates, who believes that there is a need for just three open source licences: the General Public Licence (GPL); the Lesser General Public Licence; and a version that has more restrictions for applications in commercial environments.

The latter is needed for enterprise users that want to deploy open source applications in conjunction with proprietary or home-grown solutions. The GPL would force them to disclose the source code of the proprietary software, which is unacceptable for many enterprises.

"God created GPL for a reason," Swainson said in a presentation at LinuxWorld, claiming that it is the best licence around.

There is, however, no standard for a more restrictive commercial licence. Major software vendors including CA, IBM and Sun have instead created their own versions, but these rarely get updated after they have been approved by OSI, according to Swainson.

The controversy over open source licences was sparked by the approval of Sun Microsystems' Common Development and Distribution Licence (CDDL) last January. The CDDL was used to publish the source code for Solaris 10.

Critics including the Free Software Foundation claim that the CDDL has little to do with open source, because it only grants open source rights to users that subject themselves to every aspect of the licence.

Even though OSI approved the CDDL, Novell chief executive Jack Messman told vnunet.com that he does not consider it to be truly open source. "Sun is open sourcing Solaris on its own terms. That's not open source," he said.

Messman added that he would support CA's plan to create three basic open source licences. "OSI has allowed the [open source] licence to become fragmented to suit the needs of particular distributors. We need to get fewer licences. Fewer is better," he said.