>I would then like to know if someone here on the kernel list could tell me where
>to look for something about that (pointers to good places, short descriptions
>or whatnot)
Try http://www.gr.osf.org/mklinux/
>as I'm having a little trouble to figure out how to change an
>already _existing_ OS kernel to be on top of a so called microkernel?
Changing Linux to run on top of the OSF microkernel was just like
a port: Mach offers generic machine-independent interfaces to
devices, VM, task and thread management, etc... We added new
"architectures": osfmach3_i386 and osfmach3_ppc to the already
existing ones (i386, alpha, mips, etc...) and put most of the Mach
related code into a machine-independent "osfmach3" directory.
It's just another port, but to a kind of virtual machine.
> Why not
>instead design and build a new kernel for that purpose?
Because we wanted to have a free UNIX-like system on top of OSF MK
rapidly to allow more people to develop new extensions or servers
for the microkernel. We needed a system that offers a complete
development environment (X-Window, GCC, etc...).
Apple, on their side, wanted a free popular operating system
running on top of a microkernel on the PowerMac.
> Why choose Linux when
>Linux for example already _is_ pretty portable (apparently this is an issue
>with microkernels?), which is proven practically :-)
Hmmm, will I be able to avoid starting a flame-war ? Let's say that
it all depends on what you mean by "portable". Just FYI, it took
5 months for one engineer (who wasn't a Mach nor PowerMac nor PowerPC
expert) to port OSF MK to the PowerMac and it took 2 weeks to port
the Linux server to the PowerMac.
But portability is only one of the advantages of the OSF microkernel
along with SMP-support on several platforms, real-time, distributed
IPC, distributed shared memory, scalability, etc...
Of course, you don't *need* a microkernel to run Linux on your
PC at home, and our project is more targeted towards:
* people who are doing research with microkernels,
* people who are interested in microkernels,
* people who want Linux on their PowerMacs.
I hope this mail and the WWW pointer answer your questions.
[ Francois ]
-- +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ | Francois BARBOU DES PLACES | | e-mail : barbou@gr.osf.org | | OSF Research Institute | | or : barbou@ri.osf.fr | | 2 avenue de Vignate | | phone : (+33) 76.63.48.74 | | 38610 GIERES FRANCE | | fax : (+33) 76.51.05.32 | +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+