[oshepherd]

I took a quick peek at the redox source code and found kernel mode audio and network drivers. This is not a microkernel.

As for UB: Maybe it has less, but that which exists (e.g. noalias on mut refs) is very dangerous.

[steveklabnik]

Yes, they're in the middle of some refactoring stuff; they had to put some things back in the kernel. Should be back out when they're done.

[Manishearth]

No more dangerous than existing UB in C, just that we're not used to it. And it's easy to disable for your types.

Like Steve said, the exact nature of this UB isn't completely specified yet (as in, when it actually is UB), so it is dangerous right now, but that's just temporary.