Re: mach is dead...isn't it?

["B. Douglas Hilton" <bdhilton@charter.net>]

Marcus Brinkmann wrote:
> On Mon, Aug 05, 2002 at 06:35:56PM -0400, B. Douglas Hilton wrote:
> > AFAIK, L4 just doesn't have this capability. It is faster in a
> > uniprocessing scenario, but cannot scale in its current state.
> > The L4/Hurd project is just trying to leverage existing code
> > from Hurd so that they can have a native OS for their kernel.
>
>
> I think you are mistaken about that.  The L4 project is there to make a
> microkernel design feasible at all.  I am not sure what exactly you
> are thinking about, maybe you are talking about NORMA.  But I don't think
> there is a reason why you can not implement something like that in L4
> in user space, too.  L4 doesn't intend to have such capabilities.  But
> on the other hand, it doesn't burden you with the overhead of such
> capabilities when you don't need them.  This optimizes the common case,
> and I don't think it is worse for the rare cases than Mach either.

Hmm. Yes I can see how that could be true. Keep ripping stuff out of the
kernel until you have the absolute fastest and leanest nucleus possible
and then put it all back in in user space. In that regard L4 would tend
to actually be a better match for the Hurd design philosophy: Hurd of
Unix Replacing Daemons, where "Unix" referred to the kernel, not the OS.

I guess back in those days of yore, they just figured that multiprocessing
IPC was definately still within the realm of the kernel, so they burdened
poor Mach with all that overhead... the grandpa of Beowulf!

Well, Marcus, I would think that you, Roland, and Jeff would be the experts
here. I'm dropping this thread like a hot potato before it gets out of control.
I am now out of my league :-)

L8r

- Doug