Microsoft tries to reduce Shared Source licenses down to three, or is it five?

Microsoft recently attempted to simplify their Shared Source licensing program, but may have made things more complicated instead. Under Shared Source, developers can view, modify and redistribute Microsoft code under varying levels of restrictions. Microsoft claims that the three new licenses will replace and clear up confusion with the older group of ten licenses, but does three really equal three in this case ?

The three main licenses are categorized from a least restrictive to a most restrictive version and are called "Permissive" (Ms-PL), "Community" (Ms-CL) and "Reference" (Ms-RL) licenses. Permissive allows developers to view, change and redistribute Microsoft code. In addition, they don’t have to release their source code. In contrast, the Community license requires the release of the code. The most restrictive license, the Reference license, allows developers to view, but not modify the source code. This is intended for library or device driver writers who need to know how to hook into certain Windows programs.

Microsoft says that several hundred libraries and programs have been released under Shared Source, but it’s important to note that Microsoft Office and Windows, the cash cows of the company, are currently not open to modification and redistribution. To allay fears of a secret backdoor or malicious code, Microsoft has recently allowed domestic and foreign governments to view, but not change, the source code of the Windows operating system.

While it appears that Microsoft is loosening the reigns on its software, there appears to be some drawbacks to the Shared Source program. In particular, the user’s rights end if he decides to litigate against Microsoft. "If you begin patent litigation against Microsoft over patents that you think may apply to the software (including a cross-claim or counterclaim in a lawsuit), your license to the software ends automatically," the anti-litigation clause reads.

The new licenses seem similar to open source licenses such as Gnu Public License (GPL), but Microsoft says they aren’t trying to copy anyone. A prepared statement from Microsoft’s PR agency says, "Microsoft came to these licenses after five years of sharing source code with businesses and governments. We found that the requests for code access came into three categories and this is not Microsoft replicating anything. We came up with the licenses by our own learning."

In addition to the three main licenses, the Permissive and Community licenses have two "Limited" sub-licenses. The Limited license mandates that the program and resulting code must be used on a Windows operating system. The non-Limited licenses are operating system agnostic. If you count the Limited classes as licenses, then there are really five licenses.