Shared source
From Wikipedia, the free encyclopedia
Shared source is a type of licensing program that allows controlled access to full or limited amounts of product source code. It is not a particular license, as there are several different shared source programs, each with their own license and varying restrictions.
The term is typically used to refer to Microsoft's Shared Source Initiative, though the use as a generic licensing term is growing more widespread. Shared source licensing is also used by other projects and companies, such as Hewlett-Packard and Sun Microsystems.
Though Microsoft's shared source licensing allows for source code access, it is not free software according to the Free Software Foundation, because none of the license programs allows for commercial use of modified code. [1] Most programs restrict code access to particular groups, institutions, or partners. Some programs, such as the Shared Source Common Language Infrastructure, allow non-commercial modification and redistribution of code by any users. However, Enterprise Source Licensing allows enterprise customers to view (but not modify or redistribute) the code.
A video interview with the Director of Shared Source Programs at Microsoft, Jon Rosenberg, can be found here[2].
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[edit] Benefits of shared source
Shared source licenses provide a number of benefits to end users that are not present in typical proprietary software licenses. Primary among these is the availability of source code for reference when developing complementary systems. For example, having the source code to significant portions of an operating system aids application developers in maintaining stability and consistency in their own programs. The availability of source code also permits review and auditing from a security perspective, something which many large corporations and governments are now mandating.
Shared source benefits the copyright holder in that much tighter control is kept over the use of their product than open source licenses, which generally include the voluntary abdication of many of the author's rights. From the perspective of companies which are used to developing proprietary software, this is a smaller transition to make, and may be seen as an interim step to full open source disclosure.
From an end-user and original author perspective, shared source licenses share many of the benefits (and drawbacks) of open source licenses. From a "downstream" developer's standpoint, some of the shared source licenses stop short of the rights granted by an open source license while some of the shared source licenses, such as the Microsoft Permissive License and Microsoft Community License, could be characterized as open source licenses.
[edit] Notable shared source programs
[edit] Microsoft Enterprise Source Licensing
Microsoft gives enterprise customers access to some versions of the Microsoft Windows operating systems. This is among the most restrictive of the Shared Source licenses, allowing no modifications of the code.
[edit] Microsoft Windows Academic Licensing
This program makes Windows kernel technologies and code available to universities for teaching purposes. The program also includes curriculum resources and projects.
[edit] Microsoft Shared Source Common Language Infrastructure
The first widely-distributed shared source license program is Shared Source CLI, the shared source implementation of the Common Language Infrastructure. The licensing permits non-commercial modification and distribution of the source code, as long as all distributions include the original license, or one encompassing the original terms [1].
[edit] Microsoft Community License (Ms-CL)
This is the least restrictive of the Microsoft licenses and allows for distribution of derived code so long as the modified files retain the royalty-free, non-exclusive copyright and patent grants of the original license.
On December 9, 2005, blogger and programmer John Cowan submitted this license to the Open Source Initiative for approval. [3] [4]
[edit] Criticism
Free software enthusiasts see shared source licenses as being equal to proprietary licenses. Free software pioneer Richard Stallman has said that Shared Source is "just another name for a nondisclosure agreement". Prominent open source figure Bruce Perens has described its policies as "look but don't touch—and we control everything". [5]. Surprisingly, two of the Shared Source licenses were interpreted as free software licenses by FSF Europe. However, the distribution of many licenses is considered an attempt to obfuscate the meaning of "Shared Source" and generate support from the free software community. [6]
[edit] See also
[edit] References
- ^ As written in the license, examples of commercial purposes would be running business operations, licensing, leasing, or selling the Software, or distributing the Software for use with commercial products
[edit] External links
- Opening Windows, Just a Little. Wired News. Retrieved on August 31, 2005.
- Stallman takes Gates to task over GPL. ZDNet. Retrieved on October 17, 2005.
- On 'Shared-Source' by Michael Tiemann. Open Source Initiative. Retrieved on October 17, 2005.
