From owner-freebsd-chat Mon Oct 13 04:42:58 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id EAA16423 for chat-outgoing; Mon, 13 Oct 1997 04:42:58 -0700 (PDT) (envelope-from owner-freebsd-chat) Received: from ren.dtir.qld.gov.au (firewall-user@ns.dtir.qld.gov.au [203.108.138.66]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id EAA16418 for ; Mon, 13 Oct 1997 04:42:54 -0700 (PDT) (envelope-from syssgm@dtir.qld.gov.au) Received: by ren.dtir.qld.gov.au; id VAA19154; Mon, 13 Oct 1997 21:50:44 +1000 (EST) Received: from ogre.dtir.qld.gov.au(167.123.8.3) by ren.dtir.qld.gov.au via smap (3.2) id xma019150; Mon, 13 Oct 97 21:50:29 +1000 Received: from localhost.dtir.qld.gov.au (localhost.dtir.qld.gov.au [127.0.0.1]) by ogre.dtir.qld.gov.au (8.8.7/8.8.7) with SMTP id VAA17994; Mon, 13 Oct 1997 21:42:22 +1000 (EST) Message-Id: <199710131142.VAA17994@ogre.dtir.qld.gov.au> X-Authentication-Warning: ogre.dtir.qld.gov.au: localhost.dtir.qld.gov.au [127.0.0.1] didn't use HELO protocol To: sfuqua@pulsar.cs.wku.edu (Stephen Fuqua) cc: Wes Peters cc: freebsd-chat@freebsd.org, syssgm@dtir.qld.gov.au Subject: Re: FreeBSD for Operating Systems Course References: <199710120351.WAA09609@pulsar.cs.wku.edu> <199710130146.TAA08173@obie.softweyr.ml.org> In-Reply-To: <199710130146.TAA08173@obie.softweyr.ml.org> from Wes Peters at "Mon, 13 Oct 1997 01:46:02 +0000" Date: Mon, 13 Oct 1997 21:42:21 +1000 From: Stephen McKay Sender: owner-freebsd-chat@freebsd.org X-Loop: FreeBSD.org Precedence: bulk >Stephen Fuqua writes: > > I'm writing a short paper as part of my MS comparing BSD with Linux and > > Minix for use in an undergraduate operating systems course. The idea > > would be to compare these systems in terms of using them for a class some > > C programming and some simple kernel programming exercises like adding a > > pseudo device or a "do-nothing" system call, and some code reading. > > > > At this point I see one big difference between Minix and the other two > > systems, Minix's source code is tiny compared to BSD or Linux. The author > > has intentionally kept it simple. Casting my mind back to my undergraduate OS course days, the most important aspect was simplicity, which roughly equates to size, or lack thereof. For study purposes, performance and ease of installation are unimportant. You need a system you can get your head around. You want your students to absorb some facts presumably through practical experimentation and not just theory. So, you should get the simplest device that shows some real world behaviour that they can play with, and usually break, but perhaps improve. I don't count adding a do-nothing system call as good enough. I would expect more, or not bother doing the course. At least I'd expect something along the lines of changing the scheduling policy or some paging or swapping policy. Our experiments with biasing disk priority along with CPU priority showed us how easy it is to make a total botch of things. :-) For our course, we used XINU and another homebaked microkernel (really not much more than a scheduler). These were simple enough to get your head around, and simple enough that we could easily find bits to improve. Part of the fun was writing a disk driver for some horrendously old PDP11 disk. Forget which one now, but I should have kept a souvenir. I recommend that you use Minix, together with its fine book. Linux or FreeBSD (well, you could guess which I really prefer) would be more appropriate as support tools in a compiler course, or web technology course, or whatever. Or for a year long postgrad OS research project. I think they are too complex for your average undergraduate with 20 other things on their mind. You want them to remember some of your course, not just marvel at how complex your props are. > > Have I missed anything, or been unfair anywhere? Or perhaps I've been unfair. I see a clear distinction between teaching students how to be OS users and teaching them how to be OS builders. I have assumed you want them to be OS builders. If I'm wrong, forget I was here. On Monday, 13th October 1997, Wes Peters wrote: >I welcome contrasting viewpoints, not that I'm likely to find any here. This is a little meta, but, don't you think we have a higher proportion of contrasting viewpoints over here in the FreeBSD camp than those other more fixated types? ;-) Stephen.