Shared Source Initiative
The Shared Source Initiative (SSI) is a source-available software licensing initiative launched by Microsoft Corporation in May 2001. This program provides various forms of access to the source code of Microsoft software, varying from open-source to highly restricted access. The motive behind the initiative was to offer varying levels of transparency into Microsoft's software for developers, businesses, and educational entities, while still maintaining commercial interests and security.
Licenses Within the Initiative
Under the Shared Source Initiative, Microsoft introduced several licenses, each with different levels of openness and restrictions:
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Microsoft Shared Source License: This license provides limited access to source code for developers to view and modify software under specific conditions but does not allow redistribution of modified software.
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Reference Source License (Ms-RSL): This license allows developers to view and reference the source code for understanding and educational purposes but explicitly restricts modifications and redistribution.
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Microsoft's Limited License: This highly restrictive license is generally used for specific collaborations or partnerships where source code access is necessary but tightly controlled.
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Permissive Licenses: These are more open and akin to the Open Source Initiative approved licenses, allowing broader use and modification under certain terms.
Educational and Commercial Use
Although the Shared Source Common Language Infrastructure (SSCLI) under this initiative is not suitable for commercial use due to its restrictive licensing, it serves as an educational tool. Programmers have the opportunity to examine the implementation details of many .NET libraries and to create modified versions of the Common Language Infrastructure. Nevertheless, the Shared Source CLI codebase requires specific Microsoft Visual Studio and Perl dependencies to compile.
Transition to Open Source
The evolution of Microsoft's software transparency led to later versions of the .NET framework, such as .NET Core, which have been open-sourced under the more permissive MIT License. This transition indicates Microsoft's shift towards collaboration and openness in the software development community, aligning more closely with traditional open-source software principles.
Impact and Criticism
The Shared Source Initiative has been both praised for its efforts to bridge the gap between open and proprietary software and criticized for not being as open as the Free Software Foundation or Open Source Initiative standards would require. The initiative's mixed approach has garnered attention from both educational institutions and commercial partners who seek insights into Microsoft's proprietary systems without fully embracing open-source methodologies.