Microsoft Publishes Moonlight Patent Covenant

Open SourceSoftware

Microsoft has pledged not to sue end users developing third party distributions of Moonlight, after it published the patent covenant

Microsoft has undertaken an important step after it published the patent covenant that will cover third-party distributions of Moonlight, the open-source implementation of Microsoft’s Silverlight rich Internet application platform that runs on Linux.

Novell and the Mono Project announced the release of Moonlight 2 on 17 December. At the same time Microsoft announced that it would extend the reach of its Patent Covenant to End Users of Moonlight to include third parties beyond Novell and Mono users.

The patent covenant says:

“Microsoft, on behalf of itself and its Subsidiaries, hereby covenants not to sue End Users for infringement under Necessary Claims of Microsoft and its Subsidiaries on account of such End Users’ use of Moonlight Implementations to the extent originally provided by Novell during the Term and, if applicable, the Extension or Post-Extension Period, but only to the extent such Moonlight Implementations are used as Conforming Runtimes.”

Regarding the patent covenant, Miguel de Icaza, vice president of developer platforms at Novell and founder of the Mono Project, said in a 17 December blog post that Novell worked with Microsoft “to make sure that Moonlight was available to everyone on Linux and BSD.”

In addition, de Icaza said:

“Culturally, we started on two opposite ends of the software licensing spectrum. The covenant that was issued for Moonlight 1 and 2 covered every user that used Moonlight, but only as long as the user obtained Moonlight from Novell. This is a model similar to how Flash is distributed: there is a well-known location where you get your plug-in.”


But de Icaza explained to eWEEK that this model was not so “open-source-y.” Yet, he assured readers that “Microsoft’s intention was to expand the reach of Silverlight, but the original covenant was not a good cultural fit.” And, “The new patent covenant ensures that other third-party distributions can distribute Moonlight without their users fearing … getting sued over patent infringement by Microsoft,” he said.

Further describing Moonlight 2, de Icaza said:

“Moonlight 2 is the result of love and passion to bring the Silverlight runtime to Linux.

Moonlight 2 engine consists of 142,000 lines of C/C++ code and 320,000 lines of C# code (125,000 lines of code came from Microsoft’s open source Silverlight Controls).”

In addition, de Icaza said Moonlight 2 is a superset of Silverlight 2, in that, “It contains everything that is part of Silverlight 2 but already ships with various features from Silverlight 3.”

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