Shared Source Initiative

Overview

Microsoft's Shared Source Initiative allows individuals and organizations to access Microsoft's source code for reference (e.g. when developing complementary systems), for review and auditing from a security perspective (mostly wanted by some large corporations and governments), and for development (academic institutions, individual developers, OEMs, ODMs, OBMs, IHVs, IBVs, ISVs). For example, higher-level OEMs, such as Dell, HP and Nokia, can get more source code of Microsoft Windows.

As part of the framework, Microsoft released 5 licenses for general use. Two of them, Microsoft Public License and Microsoft Reciprocal License, have been approved by the Open Source Initiative as open source licenses and are regarded by the Free Software Foundation as free software licenses. Other shared source licenses are proprietary, and thus allow the copyright holder to retain tighter control over the use of their product.

Microsoft's Shared Source Initiative has been imitated by other companies such as RISC OS Open Ltd.

Microsoft also uses specific licenses for some of their products, such as the Shared Source CLI License{{cite web

Free and open-source licenses

The following licenses are considered open-source by the Open Source Initiative and free by the Free Software Foundation.

{{anchor|Microsoft Public License}} Microsoft Public License (Ms-PL)

This is the least restrictive of the Microsoft licenses and allows for distribution of compiled code for either commercial or non-commercial purposes under any license that complies with the Ms-PL. Redistribution of the source code itself is permitted only under the Ms-PL.{{cite web According to the Free Software Foundation, it is a free software license but not compatible with the GNU GPL. Ms-PL provides a free and flexible licensing for developers using source codes under this license. However, the Ms-PL is a copyleft license because it requires the source code of software it governs to be distributed only under the same license (the Ms-PL).

{{anchor|Microsoft Reciprocal License}} Microsoft Reciprocal License (Ms-RL)

This Microsoft license allows for distribution of derived code so long as the modified source files are included and retain the Ms-RL.{{cite web

On December 9, 2005, the Ms-RL license was submitted to the Open Source Initiative for approval by John Cowan.{{cite web

At the O'Reilly Open Source Convention in July 2007, Bill Hilf, director of Microsoft's work with open source projects, announced that Microsoft had formally submitted Ms-PL and Ms-RL to OSI for approval.{{cite news

Restricted licenses

The following source-available software licenses have limitations that prevent them from being open-source according to the Open Source Initiative and free to the Free Software Foundation.

{{anchor|Microsoft Limited Public License}} Microsoft Limited Public License (Ms-LPL)

This is a version of the Microsoft Public License in which rights are only granted to developers of Microsoft Windows-based software.{{cite web

{{anchor|Microsoft Limited Reciprocal License}} Microsoft Limited Reciprocal License (Ms-LRL)

This is a version of the Microsoft Reciprocal License in which rights are only granted when developing software for a Microsoft Windows platform.{{cite web

{{anchor|Microsoft Reference Source License}} Microsoft Reference Source License (Ms-RSL)

This is the most restrictive of the Microsoft Shared Source licenses. The source code is made available to view for reference purposes only, mainly to be able to view Microsoft classes source code while debugging.{{cite web | access-date=2016-07-06}} Developers may not distribute or modify the code for commercial or non-commercial purposes.{{cite web

Criticism

Two specific shared source licenses are interpreted as free software and open source licenses by FSF and OSI. However, former OSI president Michael Tiemann considers the phrase "Shared Source" itself to be a marketing term created by Microsoft. He argues that it is "an insurgent term that distracts and dilutes the Open Source message by using similar-sounding terms and offering similar-sounding promises".{{Cite web |author-link=Michael Tiemann |access-date=2011-03-12

The Shared Source Initiative has also been noted to increase the problem of license proliferation.

References

References

1. "Microsoft announces expansion of Shared Source Initiative".
2. "Microsoft Shared Source Initiative".
3. "Microsoft Public License (MS-PL) – Open Source Initiative".
4. "Microsoft Reciprocal License (MS-RL) – Open Source Initiative".
5. "Various Licenses and Comments about Them". Free Software Foundation.
6. "RISC OS Open: Welcome".
7. Archiveddocs. "Windows Embedded".
8. "Microsoft gets the open-source licensing nod from the OSI".
9. "Microsoft Public License (MS-PL) {{!}} Open Source Initiative".
10. [https://arstechnica.com/information-technology/2007/08/evaluating-microsofts-shared-source-licenses/ Evaluating Microsoft’s Shared Source licenses] Ars Technica, 2007