Sourcefire are selling services based around a GPL product.
Not so familiar with Covalent but it appears they have some things available as GPL but if you want all the enterprise features then it isn't GPL.
Redhat is the same really, they also make their money from support. I believe you need to buy RHEL if you want the support from them, although this might have changed now.
I never suggested that GPL cannot be part of a business plan , I was just disagreeing with the statement that there are companies that sell GPL software, in all cases I can find what you are really paying for is something else not the software itself.
My point is more that there are many areas of software that this does not work in , games or most consumer software being an example.
"Using the ordinary GPL for a library gives free software developers an advantage over proprietary developers: a library that they can use, while proprietary developers cannot use it."
You can 'buy' RHEL without buying a services contract.
Sourcefire SELLS the product, flat out. If anything, they're more of a 'freemium' offering where the free product is a GPL product, and the 'premium' is a faster release cycle for patches / upgrades / definitions.
Covalent sells Apache. I've dealt with Covalent products at a number of federal installations, and I've never once seen a Covalent services rep. If their aim is to sell services, they're not doing a good job.
There are a cornucopia of other examples as well, but these are the three most fitting the description you claim doesn't exist. They do in fact exist, and are making money selling GPL software. That they also have services divisions has nothing to do with whether or not they're making money from selling software.
Apache is licensed under the apache license , not GPL.
This is an important distinction as I don't believe they could do what they do under GPL which is provide proprietary stuff on top of the open source core.
Sourcefire is selling the faster access to releases of rulesets etc, the GPL software is simply the carrot.
RHEL contains software that is not GPL and I doubt that they would stay in business without selling support.
The GPL license was designed specifically to stop people developing proprietary software on top of GPL software.
Apache is Apache licensed. Fair point, but I didn't understand that to be relevant to your initial statement (or the statement that kicked off this discussion.) If we intended to be discussing only GPLd licenses, then yes, you are correct.
As for the other two, you're still picking nits. The companies wouldn't exist without the software, and they sell it. There's still no good reason for WHY you would discount them as being irrelevent just because they're also selling other services.
Well IIRC the conversation started as a discussion about the difference between gratis and libre software as espoused by Stallman (original author of the GPL).
The crux of my argument is that with most current OSS licenses (GPL especially which is what Stallman advocates) companies can only be commercially viable by supplementing their OSS offerings by providing other products that are proprietary (i.e you are not free to redistribute) or by providing additional services on top.
I think it is a stretch to say you are selling GPL software when what people are paying you for is actually something else that is supplemental and if you didn't provide the extra then they wouldn't pay you anything. There are many good open source based businesses that is not in doubt but equally there are entire parts of the software business that simply couldn't practically release their flagship software under GPL, the games industry of course being the biggest example that springs to mind.
Not so familiar with Covalent but it appears they have some things available as GPL but if you want all the enterprise features then it isn't GPL.
Redhat is the same really, they also make their money from support. I believe you need to buy RHEL if you want the support from them, although this might have changed now.
I never suggested that GPL cannot be part of a business plan , I was just disagreeing with the statement that there are companies that sell GPL software, in all cases I can find what you are really paying for is something else not the software itself.
My point is more that there are many areas of software that this does not work in , games or most consumer software being an example.
http://www.gnu.org/licenses/why-not-lgpl.html
"Using the ordinary GPL for a library gives free software developers an advantage over proprietary developers: a library that they can use, while proprietary developers cannot use it."