Microsoft is trying to prevent people using and distributing software under the GNU General Public Licence, a free software licence, by forcing cross-patent licensing deals, according to Samba project leader Jeremy Allison.
Allison told ZDNet UK that through lawsuits such as the one launched against TomTom, Microsoft was attempting to encourage licensing deals which are proscribed under the GPL.
"You can't use GPL software and do patent cross-licensing deals with Microsoft (or anyone, for that matter) that cover the GPL software," Allison wrote in an email interview on Friday. "If you do so, you lose the rights to redistribute the software. That's the either/or choice that Microsoft is offering the industry — use our stuff, or we'll stop you using the competition."
The Samba open-source software project provides software for file and print interoperability between Linux servers and Windows clients. In 2007, Samba and Microsoft signed an agreement that allowed the organisations to strike an interoperability deal.
Microsoft's suit against TomTom alleges that the GPS company infringes on Microsoft patents pertaining to Linux. Allison said Microsoft was attempting to use these suits as leverage to encourage cross-patent deals with other companies.
"We put our software out there for everyone to use under the terms of the GPL licence," wrote Allison. "Microsoft not only doesn't want to use it (which is their right, of course), but they are trying to prevent others from using it by these legal threats. That's where I take issue with what they are doing."
However, Ronald Zink, Microsoft's chief intellectual-property counsel in Europe, told ZDNet UK last week that Microsoft was not seeking to threaten the open-source community with patent claims.
"If you think of IP and what can be achieved, IP can be used as a method of collaboration rather than a litigation-oriented approach," said Zink. "We have filed three lawsuits over patents, versus approximately 500 inbound/outbound [patent] licence deals, in the last five years. You might think of it as a currency."
Microsoft has claimed there are 235 patents that Linux software allegedly infringes, but the company has consistently declined to say which patents they are. Zink said that typically, patent licensing was done between companies and individuals.
"We will talk about patents and how they relate to our technologies, but it's on the basis of private conversations rather than openly broad negotiation," said Zink. "We are willing to license on reasonable terms, and we have covenants not to sue open-source developers or for research and development."
Zink added that the covenants, which also extend to those companies, such as Novell, which agree to cross-license, "give understanding and certainty to people".
However, Microsoft's patent moves may damage its standing in the open-source community. Allison said that Samba will not trust Microsoft as long as the software company maintains and pursues patent claims against Linux.
"While Microsoft has started to sue companies for using technologies in Linux and other free software then, no, Samba is not going to trust them," wrote Allison. "Trust is a two-way street."
Microsoft has been making outreach efforts to the open-source community, by working with Red Hat and Suse developers, and by working on interoperability. It has also encouraged companies such as Novell to sign licensing deals.
However, Allison said Microsoft's pursuit of companies such as TomTom for supposed infringement of Linux patents meant that the Samba community was wary of the software company.
Allison also spoke out about the TomTom case in February, saying Microsoft's move would alienate the open-source community.