What does Microsoft's new shared source mean for you?

We read the small print

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Analysis Open source advocates are doing what was once unthinkable - giving the thumbs up to a Microsoft source code licensing program.

The Free Software Foundation has said new licenses for Microsoft's pseudo open source program, the Shared Source Initiative, appears to satisfy the four requirements defining Free Software. Professors Larry Lessig and Ronald Mann, meanwhile, welcomed Microsoft's changes saying they reduce the number of open source licenses in use by the community.

In fact, there are five more, as of today.

This early support is a sharp contrast to the criticism levelled by the open source movement at Sun Microsystems when it launched its Common Development and Distribution License (CDDL), to cover the release of Solaris and its middleware

While any improvement to Microsoft's Kafka-esque source licensing will be welcomed by developers and enterprises, this latest set of options represents a continued, if somewhat predictably limited, evolution in Shared Source.

Permissive Society

Microsoft has introduced three top-level licenses, which dictate the terms and conditions under which code for Microsoft technologies are released through Shared Source. The three are Microsoft Permissive License (Ms-PL), the Community License (Ms-CL) and the Reference License (Ms-RL).

It's there that things start to get a bit more complicated.

Microsoft is also introducing two sub-licenses, Limited Permissive License (Ms-LPL) and Limited Community License (Ms-LCL) - that's complication enough. However, Microsoft is adding another layer, as the five licenses only apply to new code released under Shared Source; it is unclear - probably unlikely - that more than 80 Microsoft technologies already available under Shared Source will be ported to the new licenses.

Additionally, the open source-friendly noises made by Microsoft appear to be just that - noises. Ms-LPL and Ms-LCL restrict the use of Shared Source code to Windows. Code released under these sub-licenses will not, for example, find its way onto Linux.

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