OSDev.org

Just out of curiosity, what’s the most difficult OS feature that you’ve implemented or attempted and failed?

I’d say number one for me so far would have to be USB, and specifically EHCI. What a mess...

Second was probably AC97, because it took me probably a month to realize that the AC97 specifications don’t actually define how to access the registers. Thanks for nothing...

What about you guys? Is there anything more needlessly complicated than EHCI?

TCP is quite tricky.

Depends on how much you want to do yourself, and how much you are willing to port from elsewhere.

Personally, I realized rather early on that it would be much easier if the kernel had a more-or-less complete standard library to rely on (you know, instead of implementing all those little utility functions yourself in a just-almost-compliant way).

I'm still working on PDCLib.

So, that's the most difficult OS feature I've encountered, as I never got beyond that point, really.

I believe it's multiprocessor support.