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From: tgcpwd@rwb.urc.tue.nl (Wim van Dorst)
Newsgroups: comp.os.minix
Subject: Re: DOS and Minix partitions
Message-ID: <582@rc6.urc.tue.nl>
Date: 3 May 91 12:00:04 GMT
References: <1193@opus.NMSU.Edu>
Sender: news@rc6.urc.tue.nl
Reply-To: baron@wiesje.hobby.nl
Organization: Eindhoven University of Technology, The Netherlands
Lines: 34

In article <1193@opus.NMSU.Edu> kduling@nmsu.edu (Kevin Duling) writes:
> I'm having some rather serious problems between my Minix and DOS partitions.
> [stuff deleted]
> I've got a 32 Meg Seagate 138R harddrive which fdisk reports to have 939 
> [elaborate problem description deleted]

You have found the symptom of "wrong number of heads" diagnosis. I had the
same problem and found the solution.

I have an ST225 HD with four heads, and an OMTI controller for it. The
xt_wini driver asks the controller the disk parameters, and the OMTI 
controller says: two heads (and more of course). The answer it gives is
quite acceptable to Minix, which starts using the first two heads, but
using for the first 1 MByte you write twice the total amount of disk space
(2 MB thus) as half of it is not used. When you do a mkfs of say 10MB the
end of that fs will be on the 20thMB, somewhere in another partition
perhaps, it even may be in DOS as Minix doesn't care. That's what happened.

Now the solution is to find the proper set of disk parameters in the 
controller and use that. If your controller doesn't know about the proper
set of disk parameters, such as the OMTI controller (stupid thing), then
you have to find a suitable one, and hardcode the others parameters. That
was what I did for my HD. I have a patch of this available if you'll need
it. I posted it in the beginning of this year, so it may be in the archives
somewhere ftb'able.

If you want more information: drop me a line.
Met vriendelijke groeten, Wim 'Blue Baron' van Dorst.

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Blue Baron = Wim van Dorst, Voice (+31) 074-443937, (+31) 02152-42319
(-:       baron@wiesje.hobby.nl           tgcpwd@urc.tue.nl       :-)
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