Microsoft’s hire of Tom Hanrahan (right), formerly director of engineering for the Linux Foundation (and before that of the OSDL, one of its predecessors) says a lot about the company’s true open source situation.

Over two years ago, Microsoft and Novell signed an interoperability deal. Part of this agreement was a patent deal that suggested that Linux infringed on Microsoft's IP. Since then, Microsoft has signed a number more of these deals with various companies, but the Novell one is still the most famous.

Even though patent talks between Microsoft and Red Hat broke down last year before Microsoft went on to sign a technical collaboration and patent indemnity deal with Novell, Red Hat is still willing to work with the Redmond software maker on the interoperability front.

Microsoft touted its operating system interoperability partnership with Novell on Monday, saying that more than 500 customers have signed up since the program began more than three years ago.

Mary Jo Foley notes some of the highlights of Microsoft's patent/interoperability deal with Novell, following Microsoft's own press release celebrating the deal. She says something, however, that I'm not sure I agree with

Michael Meeks is a distinguished engineer at Novell. But his current project may be his toughest yet. He is in charge of tackling interoperability between Novell's OpenOffice.org productivity suite and Microsoft Office. And as with anything relating to Microsoft, this involves more than just technology.

In 2004 the European Commission found Microsoft guilty of monopoly abuse in the IT marketplace and demanded that complete interoperability information be made available to competitors. Microsoft objected to this decision and was overruled in September 2007 by the European Court of First Instance (CFI). The CFI found Microsoft guilty of deliberate obstruction of interoperability and upheld the obligation for Microsoft to share its protocol information.

The EU Commission and Microsoft have settled the browser choice issue, and the Commission will continue to monitor interoperability issues, with Microsoft posting a new and "improved" set of documents today about interoperability.

I asked Sam Ramji senior director of platform strategy at Microsoft about TomTom the other day and he claimed that patent issues aren't causing any chilling effect on his part of Microsoft's open source plans.