Becoming a Linux Kernel Programmer?

Young Grasshoopa asks: "In my 6 years of IT life, I've been a sys admin, perl programmer, and a config. mgmt. engineer. I've recently learned programming in C, and somehow ended up learning a bit of Linux Kernel programming as well. I now have developed a strong motivation to become a Linux kernel developer, but given my background, I am not sure how to approach companies or Open Source Project groups. I ask all those who were in a similar situation - how do you become a full-time kernel developer?"

Comments

Have you considered checking

[leviramsey]

KernelNewbies?

If you have, you may want to consider starting out as a kernel janitor (basically doing assloads of grunt work to build a name for yourself).

Kernel Development

[kzadot]

Well its a strange question to ask, normally one becomes a Kernel Developer, by having a need, usually unsupported hardware, and they write a driver for it.

I would consider myself a kernel developer at this stage, even before my driver is included in the mainstream kernel versions.

It sounds like you are at this stage already, so are you actually asking "How do I get a driver included in the kernel as distributed?". Well I think the answer to that is to keep submitting it to the maintainer of the relevant kernel. Things like revelance, and especially quality are important factors too.

For anyone at an earlier stage, perhaps "normal" programmers who need to learn how it all works in the kernel, I have (reccomend is too strong a word, as I have only read these 2 books on the topic) read 2 OReilly books.

Understanding the Linux Kernel, 2nd Edition and Linux Device Drivers, 2nd Edition

Of course you should also be on the linux kernel mailing list

And the rest is dependant on exactly you want to add to the kernel.

LKJP

[meowsqueak]

The Linux Kernel Janitor Project might be a good place to start.

http://sourceforge.net/projects/kernel-janitor

Prove your sk33lz

[n1ywb]

Linux "kernel development" is a pretty broad term. It can mean anything from mucking with the lowest of the low level junk to writing simple device drivers from existing templates, which mostly amounts to filling in some blanks.

Getting paid to develop low level kernel functions is probably the hardest thing to do. Partly because it's just very challanging programing. In fact a lot of it is less programing and more mathematics. If you haven't taken a class in Discrete Mathematics and done well, it's probably not for you. You may still be able to handle low level hardware interface issues, but forget about coming up with any brilliant new VM algorithms. It's also hard to get a job doing that because companies know that very few people on Earth can do it consistently well. Also, most companies don't see a direct benefit from it and therefor don't care since they can't see past their nose. They don't care that Linux will have 0(1) scheduling in two years if it doesn't increase sales tomorrow. This type of kernel development is typically bleeding edge and reserved for super-geniouses with a vision.

The easier way to get into kernel programming is probably driver development. There are a lot of companies that design computer hardware, and (hopefully) they'd all like to have Linux drivers for their products. Drivers are relatively easy to develop (once you know how), they all have a lot in common and there's a pretty good body of driver source code you can work from, and a large body of theory available in text books and whatnot. Writing everyday drivers typically isn't bleeding edge work and can be performed by your average sub-genious.

Either way, getting a job in the computer industry is hard right now. It never hurts to apply for jobs, but your odds of actually getting one will be a whole hell of a lot better if you have some kind of programming portfolio you can use to show off your stuff. Companies will be a lot more likely to hire a tried and true kernel programmer than a wet-behind-the-ears newb. So I recomend you get friendly with some of the kernel maintaners, reverse engineer some hardware, or pick a piece of the kernel and just do some work on it. Produce something good and then you can show it off when you get interviewed. You can't buy that kind of credential.

Re:start for free

[soloport]

Finding an employer who will pay you...

You make it sound so impossible. However...

Today's Going Pay Rate for a Kernel Developer:
* Excellent
* $110K
* Market
* Open
* $110K-$125K
* Competetive
* Open
* Competetive
* Market
* $80K-$95K

And that's just 10 of 56. And look at some of the salaries! And look at the fact that, it would seem, Linux is beginning to be used everywhere. Therefore, it would seem one might look forward to a long, lucrative career as a Kernel hack. No?

Exactly like any other open source project

[movement]

There's nothing unique or special in Linux kernel programming as compared to hacking on, say, Mono, or KDE.

You get into the projects in exactly the same way: start off doing some small useful things (docs, janitor work, UI design, whatever) and then sooner or later you'll inevitably find yourself maintaining a driver or whatever. Next thing you're making changes to sub system APIs, and you work from there.

There's no magic and there is no cabal.

If you're asking about specific organisations to help you on the way in, the other posters have already mentioned kernel janitors and kernel newbies, both of which are good.

I became a kernel hacker through a rather unusual route: my M.Sc. supervisor spotted missing functionality and suggested I had a crack at it.

Start with drivers

[mnmn]

Find a network card that is ill-supported in Linux and start working on it. See if you can find the card in used computer places and start tweaking the code.

A while ago when I was trying out a new kernel version I saw that one of the cards I had did not compile well. I dug into the code and saw a function name change was all that was required. I had to tweak another kernel a little to get it to compile under a new gcc version. No it didnt run well but it did compile and boot.

Just exploring like this and reading the kernel hackers guide driver guide and other things will give you a good handle on the internals, at least from the drivers perspective. Several month of kernel tweaking later, the vm, scheduler and the other stuff will become clear as you gain interest. However the market will be biggest for kernel ports to new architectures and drivers for newer network adapters. Keep your skills sharp there, build a portfolio and surf dice.com regularly.