I read on Scott Guthrie's blog the news that Microsoft will release the source code to the class libraries that make up .NET:
Today I'm excited to announce that we'll be providing this with the .NET 3.5 and VS 2008 release later this year.
We'll begin by offering the source code (with source file comments included) for the .NET Base Class Libraries (System, System.IO, System.Collections, System.Configuration, System.Threading, System.Net, System.Security, System.Runtime, System.Text, etc), ASP.NET (System.Web), Windows Forms (System.Windows.Forms), ADO.NET (System.Data), XML (System.Xml), and WPF (System.Windows). We'll then be adding more libraries in the months ahead (including WCF, Workflow, and LINQ).
The source code is released under a new license they are calling the Microsoft Reference License, this is not an open source license.
First of all, congratulations to everyone at Microsoft that made this happen. Am sure many .NET developers will be happy with this new development and there will be many genuine uses for this.
I heard a podcast with Shawn Burke where he discussed some of the history of behind this move. The discussion seemed mostly tactical, and am sure that to do this they must have presented a strong business case to their management that opening up the access to the source code (even under the MS Reference License terms) was important.
Even if the license for the code is not open source, it is an important step. Sun had done something similar with Java in the past and over time they moved towards opening more and more of it. Am still hope that one day Microsoft will open pieces of this under more liberal licenses that would allow those pieces to be used for any purposes, including Mono.
The source code that will be released goes beyond the scope of the C# source code that was released as part of Microsoft Rotor.
But like Rotor, the license under which this code is released is not open-source. People that are interested in continuing to contribute to Mono, or that are considering contributing to Mono's open source implementation of those class libraries should not look at this upcoming source code release.
At the same time, Microsoft already releases some class libraries under an open source license, the Microsoft Permissive License (MS-PL, which will soon be renamed the Microsoft Open License).
Am not sure why Microsoft did this, there have been a few theories around this, but my own guesses are:
Some of the statements are very similar to what Sun used to make about Java before they agreed to open source it:
Allowing developers to rebuild a framework, any framework, from source, and then redistribute the modified result, can introduce problems with providing support, serviceability, integrity and security of the framework itself. This is true with .NET, Java, Ruby, and other frameworks. Multiple independent redistributed modified versions of a framework can decrease the reliability and dependability of the common platform, which is not desirable. In the path we've taken here, we are seeking to balance the requirements we hear from the developer community for transparency and of reliability and dependability of the platform. In striking that balance, we believe the Microsoft Reference License is the right license for this release.
There are a number of scenarios that go beyond looking at the source code which are think are valuable in the existing Microsoft ecosystem and which is ultimately why it would be useful for some chunks to become open source.
For the above cases, people today can continue to use the Mono source code and cut and paste at will (with our super-liberal license the MIT X11 that comes with no strings attached).
But I still believe that there is a good business case for opening more stuff under the more liberal MS-PL license.
And of course, beyond the Microsoft ecosystem, there is the Mono ecosystem, where we could leverage that code if it were open source :-).
Posted on 03 Oct 2007