DragonFly kernel List (threaded) for 2003-07
Re: You could do worse than Mach ports
> :I know you said you didn't want to go all the way to Mach ports for
> :the messaging, but... you could do a lot worse.
> Well, I used mach messaging long ago on the NeXT machine. The basic
> problem with mach messages is that they are 'heavy weight'. The
> messaging system has far too much knowledge about the information
> being sent, and it presumes fairly expensive memory mapping operations
> which I believe can be avoided.
have you considered using (or maybe only borrowing ideas from) l4?
l4 is a microkernel api, that tries to do 'super-fast local IPC' (quoted
from ) and (to my understanding) maps to the light weight messaging, you
there is a sample implementation of the current (X.2) api codenamed
afaik, it does implement threads, so you may not be happy with it, but i
think it is worth at least a second (and a first, if you were not aware of
btw: i recommend the whitepaper, it makes things short ;) 
there exists a linux port (linux running in one l4 process only though)
guys over at hurd seem to also like this project.
i've also seen someone mentioning a netbsd port, but only once, so it may
not be planed currently.
l4 is performant too, according to some benchmarks.
(looking for an os, that is message based and runs on his pc)