[nSLUG] Minix and microkernel discussion

gnwiii at gmail.com gnwiii at gmail.com
Mon Jul 10 08:19:29 ADT 2006

On 7/9/06, D G Teed <donald.teed at gmail.com> wrote:
> I caught a mention of Minix 3 on Debian weekly.
> >From the wikipedia on Minix I found a
> link to a interesting discussion by Andrew Tanenbaum
> on Minix and Microkernels.
> http://www.cs.vu.nl/~ast/reliable-os/
> Linux certainly isn't the last OS to be made, and
> it seems to me that Minix, or something like it,
> could be useful in the near future.

OS X is useful today, although some will argue that any resemblance to
the original Mach OS is coincidental.

Microkernel OS's are being used where reliability is essential and
both hardware and software are controlled (embedded systems).

One way to look at current OS's is that you can have either a tiny
kernel with all important data structures maintained in userland and
passed thru the kernel to other modules, or you can have shared data
in a big kernel where it is accessible to all kernel modules.  In the
latter case, a lot of effort goes to managing the shared memory, and
(as we all know) a buggy module can easily crash the OS.

I think the key problem for microkernels in consumer and business
desktops is the fact that if you can get support for your device into
the kernel and use shared memory you can outperform competitor's
devices that rely on userland drivers.   Apple can do microkernel, but
open source it would be difficult to prevent hardware developers from
releasing patches to add device support in the kernel.   If hardware
developers feared real consequences if a bug in their code brings down
a system, their lawyers would make them stick with userland drivers.

In the long run, when there are six lawyers for every engineer, the
basic corporate desktop has more than 4 cores and every device has
ample processing capacity, microkernels will look good indeed.  One of
Tanenbaum's articles hints that some of the clueful people (those
still working -- I gather many leave either in disgust or to enjoy
their megabucks) at M$ realize that M$ screwed up WinNT and are
developing a microkernel.  Meanwhile there will still be hobbyists and
CS students running linux on old dual or quad-core hardware.

George N. White III <aa056 at chebucto.ns.ca>
Head of St. Margarets Bay, Nova Scotia


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