VistA is a collaborative community. In many open source communities, the question often arises of how to make money from open source software.
That the software source code is open to examination (the original literal meaning of "open source") is a different issue than the ones that surround the permissions to redistribute that code. The latter are really ownership of the code and permission-to-use issues.
Most software is made up of many modules, and VistA is no different. There are more than 100 separate modules, and many subroutines that can be added and changed.
The combinations of these modules determines the "flavor" of the distribution of the software platform. (That is why there are several versions of VistA.) One distribution may include proprietary modules that cannot be used in any other distribution, yet another distribution may limit itself to modules that can be freely exchanged. (In the VistA community there are examples of both.)
Here are some commonly used licenses (for software) that have attempted to grapple with these issues.
The VistA community includes a large community of volunteers and as such represents a very large altruistic effort. This includes companies who decide to contribute their own software into the public domain for free use. The continued success of sharing depends on licenses that keep software free and usable for anyone who wants to use it. However, there must be a method for VistA users and developers to make money, as well. Licensing helps protect each of these efforts. See the Wikipedia Free Software Licensing article and the GNU operating system licensing page for more complete information.
The GPLv3 license (and the Affero GPLv3 license for network-based software) intends that the software module or package is free to use in any environment, and furthermore, any software that relies on that GPLv3-licensed module must in turn also be completely free. Commercial and proprietary software packages can't use or incorporate GPLv3-licensed modules.
The Apache license has been around a long time. It is compatible with the GPLv3 license, but, unlike the GPLv3 license, it does not require modifications of software to retain the Apache license. In other words, Apache-licensed software can be used, modified, and the modified software then made proprietary (and therefore not returned to the open source community).
The BSD license is similar to a public domain license. There are currently many confusing iterations of the BSD license, mostly regarding attribution notices and advertising provided with software derivatives. The BSD license allows the option of propagation of either (otherwise-licensed) free open source restrictions or proprietary restrictions. It therefore allows a mix of (otherwise-licensed) proprietary modules and open sourced-licensed modules to co-exist in the same package. This flexibility has made the BSD license popular with complex distributions (such as the (BSD Unix-based) Mac OS X operating system, for example).
The Lesser GPL license intends that the software module or package is free to use in any environment, including in commercial and proprietary software packages. This allows companies to develop proprietary packages which include LGPL-licensed modules, from which they can make a profit. The disadvantage is that their products (which benefit from the LGPL-licensed modules) are not required in turn to be in the public domain. (Many companies often later donate their entire package into the public domain, however, after they no longer make a profit from them.)
Nevertheless, the use of this license allows companies that may already have an established product (with a license that is otherwise not fully GPL-compatible) to incorporate an LGPL-licensed module into their product (and still retain their original non-GPL license). They are merely prohibited from extending their license to the LGPL-licensed module itself, so it remains in the free open source realm.
Linus Torvalds (creator of the Linux kernel) has advocated that this license is the one that best allows open source companies to make money from their products yet still have a mechanism to give back to the community.
There is a vast array of proprietary licenses, all different. You never know what your limitations for software are unless you read every word. Most are attempts by lawyers to have an opportunity to create a lawsuit in the future. Some may be called "free" licenses but have many limitations which you will not be aware of until you are in the middle of a lawsuit. No license outside of the GPLv3 license is recommended for software that is truly meant to remain in the free and open source realm. Be careful when committing your organization to a mission-critical software package with a proprietary license. Also see this outstanding article on the "Open Source Enterprise Trap".
- This page was originally adapted from Kubuntuguide's intro to licenses.