Free and open source medical sofware advocates on the openhealth-list discussed a possible licensing difficulty between the VistA project and the recently announced Gnu Public Licensing (GPL’ing) of Sanchez Computer Associates GT.M database. The debate centers on the fact that VistA, a large collection of Veterans Administration medical software programs, is public domain. The source code for the programs are available by the Freedom of Information Act and has no license at all. However, VistA requires a database like GT.M to run.
Under the terms of the GPL: ‘…A related issue concerns combining a free program with non-free code. Such a combination would inevitably be non-free;
whichever freedoms are lacking for the non-free part would be lacking for the whole as well. To permit such combinations would
open a hole big enough to sink a ship. Therefore, a crucial requirement for copyleft is to plug this hole: anything added to or combined
with a copylefted program must be such that the larger combined version is also free and copylefted…’
The question appears to come down to whether code obtainable under the Freedom of Information Act is already considered ‘Free’ by the GPL and/or if VistA is modified to run with a GPL’ed program whether it automatically becomes GPL’ed.
The GPL, or ‘copyleft’ was developed by the Free Software Foundation in order to keep software that is released under the license and its derivative works ‘free’. Free software according to the GPL and the Free Software Foundation is frequently defined as ‘Free as in speech, not as in beer.’ to denote that the software is not free of charge, just freely available for end users to view, modify and improve.
It has at times been compared to and critized for its virus like nature in that all derivative works and any software combined with GPL’ed software, must become GPL’ed.
There are other licenses that have different restrictions, particularly with regard to commercial use of software such as the FreeBSD License. The Free Software Foundation does not consider these licenses to be ‘Free’ licenses.