Claims that the Linux operating system infringes on third-party patents have been around for years, as well as news that Microsoft owns a portion of those patents.

Now, Microsoft has put a number to those claims: 235.

The statement followed an article just published in Fortune magazine, in which Brad Smith, Microsoft's general counsel, discussed the company's strategy in "getting [free and open source software] users to pay royalties."

Microsoft's goal, the statement continued, is not to litigate on those issues; rather, it is to license its intellectual property to Linux users. For example, Microsoft and Novell entered a patent agreement in November, 2006, whereby the two parties promised not to sue the other for alleged patent violations.

To date, Microsoft and Novell have claimed some big name customer wins as a result of their deal, such as Wal-Mart, and Dell.

"Even the founder of the Free Software Foundation, Richard Stallman, noted last year that Linux infringes well over 200 patents from multiple companies," Horacio Gutierrez, Microsoft's vice president of intellectual property and licensing, said in a statement e-mailed to internetnews.com."The real question is not whether there exist substantial patent infringement issues, but what to do about them. "

In August of 2004, insurance firm Open Source Risk Management (OSRM) published a study that found Linux to be in violation of 283 issued, but not yet court-validated, software patents in the Linux kernel. At the time, OSRM identified 27 of the 283 patents as related to Microsoft.

Then, as now, Microsoft has not identified which patents the Linux kernel allegedly infringes upon. However, it is likely that some of them deal with the Samba open source file sharing application that enables Linux users to connect to Windows shared files and printer resources. The agreement between Novell and Microsoft specifically referred to Samba. In a 2006 interview with internetnews.com, Microsoft's Bill Hilf, who runs Microsoft's open source lab, said that a lot of what Samba does under the guise of interoperability is clone ability. Hilf said Microsoft has a working relationship with Samba, but noted some issues.

"They ask things of us and we say, 'That's our IP,'" Hilf said in the interview.

Microsoft's revelation counting 235 alleged patent violations comes as the Linux community prepares for the next GPL (define), version 3, which may end up being the license under which Linux and other open source applications are licensed.

It includes specific provisions intended to prevent another Novell Microsoft type deal. A final draft of the GPL version 3 is expected before the end of 2007.