Re: Topic for discussion: OS Design

From: davej@suse.de
Date: Sun Oct 22 2000 - 18:58:11 EST


dlitz@dlitz.net proclaimed...

> Could you elaborate? AFAIK, both Neutrino and exec.library are
> microkernels, and they by no means lack performance.

Whilst I've not used Neutrino, I did use exec.library for several
years (and was part of a project to rewrite the bad parts before
CBM went down the pan).

I'm not sure the point you're trying to make.
AmigaOS had Device drivers in userspace (Well, AmigaOS didn't
really have a kernel/user space divide), which generally
worked ok for the Amiga, but are not practical in Linux.

- AmigaOS didn't have to worry about issues like SMP.
  Linux runs on archs other than m68k, where we _do_ have
  to worry about such things.

- AmigaOS had no memory protection, and no concept of
  userspace/kernelspace, so it was perfectly acceptable
  for a userspace driver to handle interrupts etc, bash
  hardware registers etc..
  Linux (on x86 for example) has to run priveledged instructions
  in kernel mode, which require a context switch.

If you really think AmigaOS has anything which Linux could benefit
from, send patches. Otherwise, well...

> Even Windows is a microkernel (sort of)
> and it doesn't lack in performance that much.

This doesn't even justify a reply.
Please go read an OS internals book before you make such comments.

regards,

d.

-- 
| Dave Jones <davej@suse.de>  http://www.suse.de/~davej
| SuSE Labs

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