What is the difference between "free software" and "open source"?

[hazel]

I've always regarded these terms as synonymous but recently I've seen some posts, here and elsewhere, which treat them as different, even conflicting. Of course I know that there are proprietary programs like the Adobe Acrobat Reader which are available free of charge to users without being free in any other sense, but is there software which is truly free but not open source? Or the contrary?

[rcgreen]

IMO, there is no difference. They are alternative slogans for the
same thing. Some people, notably Richard Stallman, have expressed
a noted dislike of the term "open source", because he thinks it changes
the emphasis from the philosophical end ethical issue of freedom
toward the more pragmatic issue of open source as a software
development method that produces superior software.

A prominent advocate of the term "open source" is Eric S. Raymond.
As I said, I don't think they actually disagree over whether software
should be free "free as in freedom, not free as in free beer". It is
probably a personality conflict.

[GNU-Fan]

To me, there is a big difference.
Free Software refers to the ethics behind the movement, Open Source emphasises how software is being built. Both things are important questions, but if I had to decide, I'd opt for the first one.

In my opinion, to call it simply OpenSource is like saying "Yeah, let's do work together on this software and release it under a free license", without anybody asking "Why do we do this?".

As always you can find quite a lot of words of (strong) opinion on
Why Open Source Misses the Point of Free Software - GNU Project - Free Software Foundation (FSF)

If you want to compare by definitions,
The Open Source Definition | Open Source Initiative
The Free Software Definition - GNU Project - Free Software Foundation (FSF)

The OSI definition has 10 terms to fulfil, the FSF guys only 4. So you would expect there is a much Free Software that doesn't meet the OSI definition.
But actually I don't know any. Nor the other way around.

EDIT: I found a loophole! Point 5.
The license must not discriminate against any person or group of persons.
One could surely write a Free Software that prints out discriminatory messages.
So that could not be OpenSource then.

EDIT2: Maybe I misunderstood point 5. It refers to the license, not to the software.
So you would have to write racist, sexist, ..., comments into to license text?

[reed9]

As GNU-Fan said, free software is about ethics and open source is a development model. Or as Richard Stallman put it,

As GNU+Linux caught on, it gained many users that did not agree with free software ideals. In 1998 they formulated another philosophy, called "open source," which appreciates free software for practical benefits but declines to see the matter as a choice between right and wrong. It cites values such as power and reliability of software, rather than freedom and community. Those who hold that view have a right to promote it, but the Free Software Foundation disagrees with them, so please do not link the FSF with their slogan. We work for free software.

[techieMoe]

I agree with GNU-Fan and reed9. "Free Software" is a movement, a philosophy, and for some (like RM Stallman) a way of life. "Open Source" is a software development model that may (or may not) have people using it that believe in the tenets of "Free Software."

Linus Torvalds is a good example of this. He's an open-source developer, because his software is released under the GNU GPL license and therefore available for anyone to use. He isn't however a "Free Software" advocate because he doesn't care if his software is used for commercial (for-profit) applications. He used the GPL out of convenience, not ideals.

[reed9]

He isn't however a "Free Software" advocate because he doesn't care if his software is used for commercial (for-profit) applications. He used the GPL out of convenience, not ideals.

Hate to quibble, but Free software has nothing to do with for-profit or commercial applications.
Selling Free Software - GNU Project - Free Software Foundation (FSF)

[GNU-Fan]

As an interesting side note, Linus released his kernel under a license that would forbid commercial usage first. Then he was asked to select a license that would not.

http://www.kernel.org/pub/linux/kern.../RELNOTES-0.12

Just image if he didn't. No Intel, IBM, Google, you name it, paying people to work on it

[techieMoe]

Hate to quibble, but Free software has nothing to do with for-profit or commercial applications.
Selling Free Software - GNU Project - Free Software Foundation (FSF)

This is true, but the point I was trying to make is that Linus uses the GPL for convenience, not to be a "Free Software" advocate. I know Stallman himself has said he has no issues with people charging for GNU Emacs (he himself charged a ridiculous amount at one time).

I know this whole OSS versus FS is a powder keg, but I just can't resist throwing in this: I have much more respect for a software pragmatist like Linus Torvalds than a software idealist like RM Stallman. Now give me a minute to put on my fireproof suit.

[techieMoe]

As an interesting side note, Linus released his kernel under a license that would forbid commercial usage first. Then he was asked to select a license that would not.

http://www.kernel.org/pub/linux/kern.../RELNOTES-0.12

Just image if he didn't. No Intel, IBM, Google, you name it, paying people to work on it

I remember hearing about this in a recent interview. He had his own license in the beginning, but eventually moved to the GPL. It does boggle the mind how different the world would be.

The same goes for the inventor of Pong. He almost ended up giving the patent for what we now call a videogame to the US government. Steve Wozniak originally offered his Apple I design to Hewlett-Packard, and they turned it down. The history of computers is full of near-misses and strange coincidences.

[hazel]

I think I see the difference now. It's like the difference between those people who buy free-range organic meat on animal welfare grounds and those who do it because they think it's healthier. Or those environmentalists who champion a low-energy low-pollution lifestyle as a matter of planetary stewardship and those who merely argue that our present lifestyle is unsustainable and we'd better change it if we want to survive in the long term. One lot are idealists and the other are pragmatists but they both end up living in the same way and they both look the same to everyone else.