Section 8.2. The Classic Licenses


8.2. The Classic Licenses

The classic licenses cover a huge swath of open source software. Each has its own personality based on how and why it came into being.

8.2.1. In the Beginning: The GPL

Considered the progenitor of all open source licenses, and still the overwhelming favorite among programmers (85% of all projects, by some estimates), Richard Stallman's GPL underpins Linux and the constellation of software around iteverything from email clients to MySQL to more C++ compilers than you could ever possibly need.

The GPL stems from Stallman's ideological stance that creating "free," as opposed to closed and proprietary, software is the ethical responsibility of programmers and end users. Whether you subscribe to Stallman's belief in the "Free World" does not prevent you from using GPL-protected code or profiting from it, as MySQL and commercial distributors of Linux can attest. Nevertheless, understanding where Stallman is starting from is key to grasping the full implications of his central innovation: Copyleft.

8.2.1.1 Free, open, and Copylefted

All open source licenses share the principle that anyone should be able to use, copy, and distributeperhaps with modifications and under the right circumstancessource code and the executable software compiled from it. As you will see in this chapter, proprietary software makers dabbling in open source projects tend to have the most restrictive licenses, and the GPL does the most to ensure that software stays open.

The GPL has one notable restriction, however, and that is the idea of Copyleft. While other licenses, such as BSD's, allow users to build proprietary software on top of open source foundations, Copylefted software does not grant that right. Under the GPL, any software developed from source code licensed under the GPL is also automatically bound by the GPL. The term viral licensing, which the Free Software Foundation rejects, was invented to describe the effects of the GPLnew code based on GPL-protected work is "infected" by the terms of the license, with no allowances for the size of the code involved or its relative importance to the derivative work. (When someone uses the words viral and infect to describe the GPL, it usually means they are hostile to open source.)

The intent was to guarantee that a commercial third party would never modify and productize Copylefted open source code down the road. Use is free, to modify is free, but if you distribute the code or any modifications, you must do so under GPL terms. In some ways, this makes it harder for a programmer to make money with open source, because the software can always be downloaded for free. But it guarantees to the entire user base that all subsequent improvements will be freely available, and it eliminates the possibility of forking due to commercialization.

Mixing Copylefted code with proprietary software or attempting to distribute a closed, proprietary work based on such code is a violation of the GPL that the lawyers of Stallman's Free Software Foundation will enforce. So far, they haven't taken anyone to court, although they do actively search for violations and have become involved in disputes. The abundant amount of community hostility toward those who violate these rules helps with enforcement. Because of the GPL's mindshare among programmers and its widespread use in open source projects, the question of whether a given piece of code is compatible with the GPL is often asked during open source projects. The upcoming discussions of other licenses will indicate whether a license is compatible with the GPL.

That said, end users can modify Copylefted code and can mix it with proprietary systems, provided they keep the resulting code in-house and under wraps. The key here is distribution software developed internally on GPL code to drive business processes is allowed under the GPL. But any form of distributionnot just for sale but also passed along to a partner or shared with a third-party developertriggers the GPL, forcing the company in question to make the source code available to anyone who asks. Nondisclosure agreements do not technically override the GPL, and those inclined to play fast and loose with the licensing agreement should consider that the discovery of a GPL violation that is also part of a critical piece of software could cripple a business.

For most end users, access to the source code is of theoretical value only because programs are used as they are, and are not modified. When they are modified, the modifications are rarely distributed. The most common form of distribution is to send bug fixes or extensions back to the core development team.

8.2.2. The "Lesser" GPL

A less restrictive version of the GPL also exists for use with code libraries that are used in precompiled binary form and do not require access to source code. When Stallman recognized the fact that programmers might prefer to link certain libraries to the GPLstatically, or using a shared library and proprietary applications simultaneouslyhe created the Lesser GPL to grant them this right. Applicable only to libraries, the majority of the primary GPL's conditions still standthe source code of modified libraries must be made freely available, etc.--but the Lesser GPL allows open source applications to fit more snugly into a preexisting product development process.

8.2.3. Using the GPL in Your Own Work

Licensing code under the GPL is almost as simple as cutting and pasting. The Free Software Foundation's web site (http://www.fsf.org/) contains a full text version and multiple language translations of the GPL, along with step-by-step instructions for adding copyright notices and other pieces of necessary boilerplate language.

The Free Software Foundation does not recommend using the GPL itself as the template for a homegrown license, as the creation of a new, alternative Copyleft to the GPL's is almost certain to render it incompatible with the GPL itself and all software, including Linux, licensed through it.



Open Source for the Enterprise
Open Source for the Enterprise
ISBN: 596101198
EAN: N/A
Year: 2003
Pages: 134

flylib.com © 2008-2017.
If you may any questions please contact us: flylib@qtcs.net