Newsgroups: comp.os.minix
Path: utzoo!utgpu!cunews!bnrgate!bmerh408!bmerh451!dgraham
From: dgraham@bmerh451.bnr.ca (Douglas Graham)
Subject: Re: nice for Minix?
Message-ID: <1991Mar28.064558.15562@bmerh408.bnr.ca>
Sender: news@bmerh408.bnr.ca (Usenet News Admin)
Organization: Bell Northern Research, Ottawa, Canada
References: <1991Mar20.221512.21591@vicstoy.UUCP> <1991Mar25.093908.13426@rtf.bt.co.uk> <go.670130351@jacobs.CS.ORST.EDU>
Date: Thu, 28 Mar 91 06:45:58 GMT

In article <go.670130351@jacobs.CS.ORST.EDU> go@jacobs.CS.ORST.EDU (Gary Oliver) writes:
>
>Just thought I'd put in a good word for the nice "nice" package submitted
>by Kai-Uwe Bloem recently.  It works "nice"ly.
...
>I'm not certain, but if people would try this, the cry about having a
>"threaded" fs may die down.

The cry seems to pretty muted these days.  Partly because the FAQ goes
out of it's way nip such talk in the bud.  This is unfortunate, because
even if it never got implemented, it would (and did) lead to some
interesting discussions on alternate O/S designs.  It's too bad that
this group doesn't see more of those types of discussions; the type
that us lifelong students of O/S design could learn something from.

A better scheduler helps, but it's no panacea.  It will always seem
silly to me that I have to wait to send a character to the console,
while the floppy driver waits for a bunch of interrupts.  It's not
likely to get any better when I finally get around to writing the
tape driver that I so badly need.

>The package is a much simpler way to
>get most of the performance asked for and it is in keeping with the
>spirit of Minix : simple and effective.

Is Minix really all that simple?  Maybe it's just me, but I find
that some of the task interactions are really quite complicated
and convoluted.  A non preemptable passive kernel, with many
equivalent user processes vying for resources seems to me to be a
more understandable model.  But like the FAQ sez, if you want it,
do it yourself...

>  It's a pretty classical
>implementation of process priorities with queue pre-emption and
>should, at least, be representative of topics discussed in any
>OS class worth taking.

Yup, along with virtual memory, disk scheduling algorithms,
discussions on maximizing throughput...
---
Doug Graham   dgraham@bnr.ca   Bell-Northern Research, Ottawa Ontario Canada
