The difference between open source and zero-cost

I was inspired to write a few words about how people interpret the words “open source” and conditions under which this software may be obtained.  Some time ago I read a message posted on the Joomla forum that implied (in my mind) open source was synonymous with free of cost.  The forum topic began with the words “I read that <product-X> was open source; its programmers now charge $x per year.  Having scoured the web, I can't find a truly open-source alternative to <product-X>.  Is there a one?”

This kind of “reasoning” is a little disturbing because it conflates several unrelated issues and, in replying to that topic, I attempted to explain that people should exercise care in discussing open source development, cost and licensing.

There is a good explanation of open source here:  In a general sense, open source means software code that may be “inspected , modified or enhanced”.  Some people have a more narrow interpretation of open source:  some people argue that true open source is software that embraces and “celebrates principles of open exchange, collaborative participation, rapid prototyping, transparency, meritocracy, and community-oriented development.”  In both senses, I think it's true that Joomla! is open source but this does not mean that all open source projects involve collaborative participation, “transparency” or community-oriented development.

Joomla! (and most of the extensions written for it) is licensed under the GNU General Public Licence.  Not all open source software is licensed the same way.  Joomla! is free (both in the freedom to use it and in terms of the financial outlay involved) but not all open source software is “free” in an identical manner.

Open source software, licensing and cost are completely separate matters:

  • Open source ⇏ GNU General Public Licence
  • GNU General Public Licence ⇏ freeware/groupware/shareware
  • Free software ⇏ open source software
  • Open source ⇏ freeware/groupware/shareware

Examples of free, open source software (GPL-licensed vs. non GPL-licensed):  Joomla! vs. WikiMedia

Examples of GNU GPL products (free/shared vs. paid):  Akeeba Backup Core vs. Akeeba Backup Professional

Examples of free software (open source vs. not open source):  Mozilla Firefox vs. Google Chrome, Chromium vs. Google Chrome

Examples of open source software (free/shared vs. paid):  MySQL vs. Ingres

In summary, people can choose open source products (e.g. OpenOffice) or proprietary products (e.g. Microsoft Office), products that they can obtain for zero-cost (e.g. OpenOffice) or products they have to pay for (e.g. Microsoft Office), GPL-licensed products (e.g. Midori) or products licensed differently (e.g. Internet Explorer) … or anything they choose.  Open-source has little to do with range of “alternatives” that available.