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From: Paul.Northover@dundee.ncr.com
Newsgroups: comp.os.minix
Subject: Re: PC Minix demo (questions)
Message-ID: <46961@nigel.ee.udel.edu>
Date: 8 Mar 91 10:27:47 GMT
Sender: usenet@ee.udel.edu
Lines: 49

In an article Andy Tanenbaum <ast%CS.VU.NL@VM1.NODAK.EDU> writes:
>In article <1991Mar5.214921.1010@unixg.ubc.ca> twong@civil.ubc.ca (Thomas Wong)
> writes:
>>What happens with me is I would reboot with the demo disk, the first
>>menu comes up, I choose = and the cursor moves to the next line as if it
>>accepted my command but then just sits there.
>
>I'm surprised at this behavior and don't know what is causing it.  I do know
>that MINIX regards a 360K diskette in a 1.2M drive as a quite different
>beast than a 360K diskette in a 360K drive or a 1.2M diskette in a 1.2M drive.
>These combinations all have different minor device numbers.  Perhaps the
>problem is related to this somehow.

I have tried the following:

1. Formatted a 360K diskette in a 1.2M drive, I have an entry in my congig.sys
   to create drive 'D:' as a 360K drive so I just have to enter 'format D:' to
   make a 360K drive. I then wrote the demo to it using RAWFILL, which was
   posted to the group a few weeks ago.

   This disk was then booted up and ran fine, all this was done on an NCR 286
   based AT clone.

2. I took the disk created in 1 and booted it in an NCR 386 machine with a 1.2M
   drive as drive A. It brought up the initial menu and I selected '='. Almost
   immediately minix crashed with a kernel panic.

3. I repeated the process in 1 above, but this time on an NCR 286 machine with
   a 1.44M drive A. This time I formatted a 720K diskette and again it booted
   without any problems. Incedentally I did format the diskette to 720K, it
   wasn't necessary in my case to try and make it format as 360K.

4. I took the disk created in 2 and booted it in an NCR 386 machine with a
   1.44M drive A. Again I got a kernel panic after pressing '='.

The summary of all this is that I only had problems booting the demo on 386
based machines, and the problem appears to occur when minix attempts to load
the root file system from the demo disk. As others have loaded full minix on
to 386 based machine the only explanation I can think of is that it is related
to the combination of boot disk and minix file system on a single disk. I can't
take it any further myself as I have ST-MINIX :-), so I have no access to
PC-MINIX sources.

Hope this will be of some help in solving this problem.

Paul Northover				<Paul.Northover@Dundee.NCR.COM>
NCR Self Service Systems
Dundee
Scotland