Continuation of the Mach Microkernel
Andrew Reilly
andrew-freebsd at areilly.bpc-users.org
Tue Jan 25 00:17:53 PST 2005
On Mon, Jan 24, 2005 at 08:46:28PM -0800, Justin Walker wrote:
>
> On Jan 24, 2005, at 19:50, Andrew Reilly wrote:
>
> >On Fri, Jan 21, 2005 at 04:51:51PM -0500, Nicholas Ink wrote:
> >> Has anyone tried running the Mach microkernel with a new version of
> >>FreeBSD, like 5.x? I'm working on a project involving that
> >>microkernel, but I'm concerned that it won't work with newer versions
> >>of FreeBSD.
> >> Does anyone know anything or know of any resources that might assist
> >>me?
> >
> >How about the Darwin codebase? They recently upgraded their
> >user-land to FreeBSD 5.something, I believe.
>
> Nope. The Darwin kernel uses some updates from FreeBSD 4.x, not 5.x.
I specified user-land, but the web pages on developer.apple.com
indicate that synchronization-with and tracking of
FreeBSD-stable is ongoing work. -stable now refers to 5.x, and
I can't imagine them not wanting to incorporate some of the 5.x
fine-grain locking work as it settles down. After all, there
are plenty of multi-processor Mac boxes out there.
> It isn't a wholesale import of FreeBSD, though. The device driver
> model is completely different, as is the interface between the network
> stacks and the devices.
True.
> Also, just to be clear, Darwin doesn't use Mach as a microkernel. The
> implementation is more like Mach 2.x than Mac 3.x (even though the Mach
> bits are based on Mach 3.x): there is no support for running "guest
> OSs" in Darwin.
I've often been puzzled why anyone using the Mach +
BSD-single-server combination bothered with the "microkernel"
moniker. Where's the win, there? Surely if you want a
microkernel, then you look towards QNX, Hurd, Amoeba, L4 et al.
Since FreeBSD was mentioned in the single-server context, I
assumed that microkernel-ness wasn't important. I am interested
in these issues, but haven't had the time or opportunity to
investigate them myself, yet.
Cheers,
--
Andrew
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