Open Source Derivative Works Can Be Scary

"Many users of open source software are frightened by the term "derivative works." They worry that they might accidentally create derivative works that will infect their own proprietary software." This is particularly true if the open source software being used or linked to is distributed under the GNU General Public License (GPL) or the Open Software License (OSL), both available at www.opensource.org/licenses. This is so because the GPL and OSL require that derivative works be offered to the public under the terms of the applicable license.

This article by Lawrence Rosen provides a good summary of the issues involved and the emerging law in this area. He suggests the following as guides in determining whether a derivative work has been created:

"Here’s how I would decide in the edge cases that I described above:

· The primary indication of whether a new program is a derivative work is whether the source code of the original program was used, modified, translated or otherwise changed in any way to create the new program. If not, then I would argue that there is not a derivative work.

· The meaning of derivative work will not be broadened to include software created by linking to library programs that were designed and intended to be used as library programs. When a company releases a scientific subroutine library, or a library of objects, for example, people who merely use the library, unmodified, perhaps without even looking at the source code, are not thereby creating derivative works of the library.

· Derivative works are not going to encompass plug-ins and device drivers that are designed to be linked from other off-the-shelf, unmodified, programs. If Linux is designed to accept separately-designed plug-in programs, you don’t create a derivative work by merely running such a program under Linux, even if you have to look at the Linux source code to learn how to do so.

· In most cases we shouldn’t care how the linkage between separate programs was technically done, unless that fact helps to determine whether the creators of the programs designed them with some apparent common understanding of what a derivative work would look like. We should consider subtle market-based factors as indicators of intent, such as whether the resulting program is being sold as an “improved” or “enhanced” version of the original, or whether the original was designed and advertised to be improvable 'like a library.'”