Different categories of software licences
Software licences can be broadly classified into two categories. These are: proprietary licences and the free/ open source licences. The former are adopted by software companies or individual developers to include one or more restrictions on how the software is used by a customer. Proprietary licences can restrict modification, sharing, inspection, redistribution and reverse engineering. Some of the popular proprietary licences are supported by organisations and companies like The Open Group (Yes! UNIX is closed source!), Microsoft, Adobe Systems, etc. Microsoft Windows’ EULA is an example of a proprietary software licence. To those in the software freedom movement, proprietary licences are anathema. So I am going to discuss what interests us more -- the open source software licences. But don’t forget that having some licence is far better than no licence at all.
Open source software is widely supported by many enthusiastic developers. One of the reasons for such untiring support is the idea that with each line of code contributed, we are working towards the development of mankind by spreading knowledge. But are we fighting on the right side for the right reasons? To answer this question, we need to understand the different free/open source licences. It is often confusing when people talk about free software, open source software, free and open source software, etc. Are they different or synonymous with one another? The answer is that they are all different. But the differences are very subtle and often do not seem to make much sense.
There are many organisations in the open source arena dealing with software licences. Two of the major players are the Free Software Foundation (FSF) and the Open Source Initiative (OSI). They both review free/open source software licences for their legal validity and usefulness. If a particular software adopts a licence approved by the FSF, then it is called free software. Similarly, if a software adopts a licence approved by the OSI, it is called open source software. Most often, licences are approved by both the FSF and the OSI, and such software can be called free and open source software (FOSS). For example, open source licences like the GNU General Public License (GPL), the MIT License and the PHP License are accepted by both the FSF and the OSI. So software that has one of these licences can be called FOSS. Artistic License version 1.0 is accepted by the OSI but not by the FSF. So software adopting this licence is open source software but not free software. Similarly, the original BSD License is accepted by the FSF but not by the OSI. So software adopting this licence can be called free software but not open source software.
So we have now learned to identify free software and open source software. But why should there be two rival organisations working towards achieving more or less the same goals? In my opinion, this is the curse associated with the free/open source initiatives. You can go to the respective websites of these two organisations and find articles mildly critical of the other initiative. The OSI argues that the FSF approach is more philosophical in nature rather than being a practical one. The OSI feels that the term ‘free’ is misleading and ambiguous. Well, many people care more about free beer than free speech so OSI scores a point there. But the FSF has its own list of accusations against the OSI. The FSF feels that the OSI licences are slightly weaker than the FSF licences. FSF also accuses the OSI of supporting companies providing software residing on the fringes of freedom and openness. This infighting can also be generalised as the main theme of open source software development.
The story goes like this. Two friends, who are developing a free/open source project, have a breakup. The next day, one of them forks the project and after a few years there are two software with differences so minute that you need advanced degrees to identify them. One such instance is the birth of LibreOffice from OpenOffice. The latter now has an Apache License whereas LibreOffice has a Mozilla Public License v2.0. The reason for the split was mostly related to the intricacies of the licence used by Oracle, which owned OpenOffice at that point in time. The bottom line is that both FSF and OSI validate software licences for their potential usefulness, and the criteria for evaluation have only minor differences but the rivalry is intense. So, finally, which initiative is the better one? Well, I don’t want to answer that question as it might trigger something similar to the ‘editor war’.