Kroah-Hartman describes the role of trust in the open source Linux development process:
I maintain the subsystems such as USB, and I have people who I trust enough that if they send me a patch, I’ll take it, no questions asked. Because the most important thing is I know that they will still be around in case there’s a problem with it. [laughs]
And then I send stuff off to Linus. So, Linus trusts 10 to 15 people, and I trust 10 to 15 people. And I’m one of the subsystem maintainers. So, it’s a big, giant web of trust helping this go on.
Other people have described this behavior as "meritocracy", or as "reputation-based development". It's a fascinating look inside the social aspects of the software development process, and it's interesting how much of the overall development process involves non-technical topics:
Companies want to get the most value out of Linux, so I counsel them that they should drive the development of their driver and of Linux as a whole in the direction that they think makes the most sense. If they rely on Linux and feel that Linux is going to be part of their business, I think they should become involved so they can help change it for the better.
Kroah-Hartman talks about the increasing maturity of Linux:
we don’t gratuitously change things. A big part of what drives that change is that what Linux is being used for is evolving. We’re the only operating system in something like 85 percent of the world’s top 500 supercomputers today, and we’re also in the number-one-selling phone for the past year, by quantity.
It’s the same exact kernel, and the same exact code base, which is pretty amazing.
In fact, he goes so far as to make a rather bold prediction: Linux is now so well established that it cannot be displaced:
I just looked it up, and we add 11,000 lines, remove 5500 lines, and modify 2200 lines every single day.
People ask whether we can you keep that up, and I have to tell you that every single year, I say there’s no way we can go any faster than this. And then we do. We keep growing, and I don’t see that slowing down at all anywhere.
I mean, the giant server guys love us, the embedded guys love us, and there are entire processor families that only run Linux, so they rely on us. The fact that we’re out there everywhere in the world these days is actually pretty scary from an engineering standpoint. And even at that rate of change, we maintain a stable kernel.
It’s something that no one company can keep up with. It would actually be impossible at this point to create an operating system to compete against us. You can’t sustain that rate of change on your own, which makes it interesting to consider what might come after Linux.
For my part, I think the only thing that’s going to come after Linux is Linux itself, because we keep changing so much. I don’t see how companies can really compete with that.
I'm not sure I really believe it is "impossible"; perhaps this is one of those claims that people will laugh at, 50 years from now, but in my opinion the Linux work is astonishingly good. I run lots of different Linux distributions on a variety of machines and without exception they are solid, reliable, and impressively efficient.
It's a very interesting software development process and I enjoyed reading this interview and recommend it for those who are interested in how open source software development actually works.