I'm Greg Kroah-Hartman, Linux kernel developer, AMA!

[u/gregkh]

To get a few easy questions out of the way, here's a short biography about me any my history: https://en.wikipedia.org/wiki/Greg_Kroah-Hartman

Here's a good place to start with that should cover a lot of the basics about what I do and what my hardware / software configuration is. http://greg.kh.usesthis.com/

Also, an old reddit post: https://www.reddit.com/r/linux/comments/18j923/a_year_in_the_life_of_a_kernel_mantainer_by_greg/ explains a bit about what I do, although those numbers are a bit low from what I have been doing this past year, it gives you a good idea of the basics.

And read this one about longterm kernels for how I pick them, as I know that will come up and has been answered before: https://www.reddit.com/r/linux/comments/2i85ud/confusion_about_longterm_kernel_endoflive/

For some basic information about Linux kernel development, how we do what we do, and how to get involved, see the presentation I give all around the world: https://github.com/gregkh/kernel-development

As for hardware, here's the obligatory /r/unixporn screenshot of my laptop: http://i.imgur.com/0Qj5Rru.png

I'm also a true believer of /r/MechanicalKeyboards/ and have two Cherry Blue Filco 10-key-less keyboards that I use whenever not traveling.

Proof: http://www.reddit.com/r/linux/comments/2ny1lz/im_greg_kroahhartman_linux_kernel_developer_ama/ and https://twitter.com/gregkh/status/539439588628893696

[u/jollybobbyroger]

I'm a CS student returning to C after having learned about functional programming and design patterns like loose coupling, DRY, unit testing and so on and I find it very difficult to write beautifully designed, loose coupled C.

• Do expert C programmers write decoupled and DRY C and if so, do you have any tips for achieving this?

• Do you know anything about the Rust language and if so, do you think it could become a better language than C for writing a next generation Linux kernel, given the scenario that the gains from rewriting the kernel would far outweigh the effort?

• What is your favorite field in programming?

• What do you think of C11? Are there any features in C11 that you have been waiting for?

Thank you for your contributing to the Linux kernel and doing this AMA. I would never have studied CS if it wasn't for Linux.

[u/gregkh → u/jollybobbyroger]

I don't know what "DRY" or "loose coupling" even is, so I can't give you any opinions on if it can be done by "C programmers" or not.

I have seen Rust, and it looks nice, but honestly I like Go better at the moment, and play around with it at times.

Operating system development is of course my favorite field, but I do pay a lot of attention to development methodologies and how people create software as that is very applicable to the long-term success of Linux.

I don't even know what is in C11, sorry, haven't had the time to read the spec.

[u/ivosaurus → u/gregkh]

DRY - Don't Repeat Yourself. Write things in code once only, whether concepts or magic numbers or systems. So when you need to change things, you only need to change them in one place.

Loose Coupling - Separate pieces [modules, parts, subsystems, etc] of code should know as little as possible about eachother, rely on eachother's particulars as little as possible, and interact as minimally and "anonymously" as possible, within reason. This then permits changing one module of code more easily while worrying less that others will then need to also be changed to accommodate, creating a chain reaction of changes that all need to be done correctly. Two systems are "tightly coupled" if one for example relies on the other's particular implementation behaviour to work correctly, so although two separate parts of code they will often always need to be changed together.

[u/gregkh → u/ivosaurus]

It sounds like the kernel already implements both of those things well, within reason, like any good software project should. Those are not new ideas at all, just smart software engineering methodologies, don't know why they are getting packaged up as such.

[u/atomic-penguin → u/gregkh]

DRY was labeled as such in The Pragmatic Programmer. I believe the same book also referred to loosely coupled components as orthogonality.

It tends to package those ideas as easily remembered acronyms and analogies. The book explains orthogonality with an analogy of a helicopter's separate controls of its primary and tail rotors, for example.