The Four Freedoms of Free Software
Ximena uses an app on her phone to keep track of the accounts for her mom's little corner store. One day the app disappears from the app store and all her data is trapped. Her cousin Diego, on the other hand, uses a program that he can copy, review, and fix himself, or ask someone in his community to fix. What is the difference between the two programs? What is it that really makes software "free"?
Source code: the program's recipe
A program is written in a language that people can read, called source code. Afterward it is "translated" into an executable file that the computer understands, but that almost no one can read or modify anymore.
Think of a cooking recipe. The source code is the complete recipe: ingredients and steps. The executable is the finished dish. With the dish you can eat, but you don't know how it was made, and you can't change the salt.
The four freedoms
Free software is defined by four freedoms. They are numbered starting from zero, as is often done in programming. Look at the diagram: freedom 3 is marked with a "?". Before reading the table, try to guess what goes there.
| Freedom | What it allows | Example in a school project |
|---|---|---|
| 0 | Use the program for any purpose | Install it on all the computers in the classroom |
| 1 | Study how it works and adapt it (requires source code) | Read the code to understand how it calculates an average |
| 2 | Distribute copies to help other people | Pass the program to a classmate who doesn't have internet |
| 3 | Improve the program and share the improvements | Translate a menu and publish your version for the group |
The program's official glossary sums it up this way: access to the source code, modification, code improvement, and distribution. Each freedom has its reason: 1 and 3 need the source code; without it, only the permission to use would exist.
The diagram shows the four freedoms of free software. State them in your own words: what does each one allow you to do? Freedom 3 is marked with «?»: complete it and…
The diagram shows the four freedoms of free software. State them in your own words: what does each one allow you to do? Freedom 3 is marked with «?»: complete it and give an example of how you would exercise each freedom in a school project.
Free is not gratis
"Free" is about freedoms, not price. There are two opposite and very common mistakes:
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Believing that everything gratis is free. False: many gratis apps are proprietary; you can't see their code or modify them, and sometimes you "pay" with your data and your attention.
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Believing that free software can't be sold. False: you can charge for a copy, for installing it, for providing support, or for training, as long as whoever receives it keeps the four freedoms.
| Gratis | Paid | |
|---|---|---|
| Free | A free text editor that you download at no cost | A GNU/Linux distribution sold on a USB drive with support |
| Proprietary | A gratis game with ads, with no code available | A commercially licensed office suite |
A classmate claims: «free software is software you download for free». Correct the sentence by explaining the difference between free as in freedom and free of charge,…
A classmate claims: «free software is software you download for free». Correct the sentence by explaining the difference between free as in freedom and free of charge, and give an example of each case: a program that is free of charge but not free software, and a free software program that is sold.
Free and open source
You may have heard of "open source." It is very similar to free software and the programs are usually the same, but the emphasis changes:
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Free software: it talks about rights and values. What matters is that people control the technology they use.
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Open source: it talks about the technical and commercial advantages of having visible code: better quality, more collaboration.
What it is for: communities with limited infrastructure
Imagine a high school in the Sierra Norte of Oaxaca, with a few old computers and a slow connection. With free software:
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It is installed without paying for licenses on all the computers and copied from a USB drive (freedoms 0 and 2).
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It is adapted to old computers and to the community's language, for example by translating menus (freedoms 1 and 3).
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Technological dependence is reduced: the school is not tied to a company that can raise prices or cancel the product.
This connects with the focus of the course: technology should be something people can make their own, not just consume.
A teacher downloads a free spreadsheet program, fixes a bug in its code and shares the fixed version with other schools. Identify which freedoms she is exercising in…
A teacher downloads a free spreadsheet program, fixes a bug in its code and shares the fixed version with other schools. Identify which freedoms she is exercising in each action and explain which of them would be impossible if the program were proprietary.
Go back to the beginning: Ximena's app was proprietary, so its owner decided everything and she couldn't keep it or fix it. Diego's program is free: it has source code and the four freedoms, which is why his community can keep it alive.