Linux is, of course, both free and open source software, but what do we mean by these terms and why is it important to understand the difference. Firstly, we should be aiming to use and promote Free Software. All Free Software is Open Source Software. But just because software is Open Source it does not mean all the freedoms are associated with it.
We must understand that when we talk of FREE we are more talking about FREEDOM or LIBERTY and not simply about “no cost”. Often we say free as in FREEDOM not as in free beer. Free software is an advantage that applies to software users, those at home, in education and those who use it in business. They are free to do what they will with the software, to run it, to share it and to distribute it, as well as being able to learn from it and study it. The Free Software Foundation is a charity that has been formed to promote, police and educate in this field. They classify free software of “libre” software using 4 measures of freedom:
- Freedom to run the software in any way that you wish
- The freedom to study how the program works which dictates that the software must also be Open Source
- The freedom to share the program with others
- The freedom to distribute you own modified versions of the software
It also has to be understand that, often, when you purchase software you only purchase a license to run the software but that license can be revoked at any time. You are also likely to be limited to the amount of devices that you can run the software on.
Open Source Software
Open Source Software or OSS is not necessarily “free”. OSS is just one of the four freedoms. The term Open Source” means that you can see how the program operates but the definition does not mean that you have all the freedoms associated with free software. Accessing the source code allows you to see how the program was made, the language that went into the program, but just because you can see the code does not mean that you are authorized to modify and distribute you modified code. So even though all Free Software is by definition Open Source; Open Source software in not necessarily Free Software and it is important to make clear the difference.