My mistake. That's Open Source. In a bid to get the European Union off their back after their stunning defeat in the EU's anti-trust trial, Microsoft has now licensed some of its proprietary code to the company that developed "Samba," software that allows operating systems other than Windows to communicate with a Windows client.
So basically what Samba does is to provide interoperability between closed-source servers (Windows) and open-source ones. Samba debuted back in 1992 and since then it has grown into a popular, community-supported alternative to other SMB/CIFS implementations.
However, interoperability with Windows servers was often hindered by Microsoft’s protocol formats modifications operated in its proprietary code. Moreover, Samba was at risk of being sued by the Redmond behemoth for infringing the latter’s patents, because Samba translates data from different formats into Windows-compatible formats.
Initially, the company which now dominates the PC and server operating systems market (with 95% and 70% market share respectively) had refused to make any patent license compatible with the open source business model and demanded a royalty rate of 5.95 % of revenues for a combination of access to the secret interoperability information and for a patent license.
The price? A token 15,000 Euros, and the royalty rate was reduced to less than half of one percent by the court order anyway. This more or less means that Microsoft has complied with the EU court directive to become more "interoperability-friendly." I guess. Who really knows? That's sort of a strange, vague term for a court to use when directing the largest software company in the world to show their competitors their closely-held information. That's OK with the EU, I imagine, as they can sue Microsoft again later, levy another huge fine, and demand that they become "interoperability-friendlier."