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Date: Sun, 24 Nov 1996 11:26:37 +1100
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199611240026.LAA09348@godzilla.zeta.org.au>
To: msmith@atrad.adelaide.edu.au, rgrimes@GndRsh.aac.dev.com
Subject: Re: 2.2-ALPHA install failure
Cc: fenner@parc.xerox.com, freebsd-current@FreeBSD.org, jkh@FreeBSD.org,
        phk@FreeBSD.org
Sender: owner-current@FreeBSD.org
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>The changed behavior in the install programs to do 1/1 translation is
>what is brain damaged, that causes more grief than I have ever seen,

Your PR seems to be missing :-).

>so Rod's Rule when doing a ``dangerously dedicated'' install is to
>always override the bios geometry with X/64/32, and turn off extended
>(DOS >1G) translation on adaptec and buslogic cards, the NCR deals
>with the translation automagically, and in conformance with the SCSI
>BIOS PnP Spec.

Bruce's rules are:

1. Don't use `dangerously dedicated' unless you know what you're doing.
2. Always override the BIOS geometry with X/255/63, and turn on
   extended (DOS > 1G) translation on buslogic cards (the ncr deals
   with the translation automagically, and I don't know about adaptec).
   This minimises problems with cylinders >= 1024 for the non-dedicated
   case and doesn't hurt for the dedicated case.
3. Rule 2 is unnecessary for drives smaller than 1G and doesn't work so
   well for drives larger than 8G.  64/32 is OK for small drives and
   255/63 is the best possible for large drives.
4. For IDE drives, just run the BIOS setup and use whatever geometry it
   gives.  This is often the geometry that you told it.  Tell it to use
   a geometry with <= 1024 cylinders if possible.

Bruce