Red Hat always sold support for their enterprise level software. A RH representative told me that they "get community software, get it to enterprise level, and sell its support. The code is always open". They also sold their technologies as services. They've never sold code or distributions per se.
Their business model allowed them to develop KVM and OpenShift.
Debian gave birth to the biggest number of derivative distros. They're the biggest and most mature base. Even Ubuntu is a Debian derivative.
While there are no enterprise software that I know (my domain doesn't overlap with "enterprise software"), I'm aware that some of the heavy hitters in the software world have their killer features based on open source software or algorithms (Photoshop's content aware fill comes to my mind which is based on resynthesizer of GIMP).
> I guess those Red-Hat boxes at my parents' basement are a piece of imagination.
No, they are not, but Linux distros were never small (except Slackware & Gentoo), so many of us were unable to download them (with 56kbps modems). We bought the complete CD sets, which were essentially repositories on CDs. I had SUSE 6.0 box set.
A generation has abused university networks to download ISO files and write them to discs. That's why most universities had local repositories for a considerable amount of time. Many still have. The place I work hosts country-wide official repositories of most Linux distributions.
> Great, and how much money do they earn from it?
Why not ask to the non-profits which govern the money and assets of the Debian and other projects? The page is here [0]. Looks like Google is also a donor in SPI which hosts Debian, PostgreSQL, Arduino/ArduPilot, Arch, etc.
BTW, most Debian and open source developers don't do it for the money. They build the software for fun and use their skills in their day-job to do their work. Also, there are many developers paid to work on open source code and implement the required features. Glibc's developer is (was?) an RH employee for example. Intel pays developers to implement their open source network and graphics drivers. AMD's both open and closed source driver teams (yes there are two, isolated teams) are on AMD's payroll.
Open Source software is sustainable. You pay for knowledge and the effort, not the code.
The growth in dual-licensing adoption, FOSDEM and Linux Summit talks regarding how to keep FOSS safe from EEE seems to prove otherwise, regarding GPL long term survival.
Their business model allowed them to develop KVM and OpenShift.
Debian gave birth to the biggest number of derivative distros. They're the biggest and most mature base. Even Ubuntu is a Debian derivative.
While there are no enterprise software that I know (my domain doesn't overlap with "enterprise software"), I'm aware that some of the heavy hitters in the software world have their killer features based on open source software or algorithms (Photoshop's content aware fill comes to my mind which is based on resynthesizer of GIMP).