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Date:      Fri, 22 Mar 1996 11:06:56 -0700 (MST)
From:      Terry Lambert <terry@lambert.org>
To:        bde@zeta.org.au (Bruce Evans)
Cc:        bde@zeta.org.au, terry@lambert.org, andreas@knobel.gun.de, dave@kachina.jetcafe.org, freebsd-hackers@freebsd.org
Subject:   Re: Adding a damn 2nd disk
Message-ID:  <199603221806.LAA02936@phaeton.artisoft.com>
In-Reply-To: <199603221426.BAA09417@godzilla.zeta.org.au> from "Bruce Evans" at Mar 23, 96 01:26:16 am

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> >The driver for old MFM drives should read the CMOS drive table.
> 
> This fails for
> - old BIOSes (e.g. 1987 Award) that don't have a CMOS drive table
> - old BIOSes (e.g. 1987 Award) that don't have a suitable CMOS drive index
>   (I used the index for a 979(?)-cylinder disk for my 988- and 1314-
>    cylinder disks and had no problems using the cylinders beyond the
>    end under systems that didn't believe the BIOS).
> - more than the number of old MFM drives supported by the BIOS.
> 
> Anyway, the driver for old MFM drives should use the geometry reported
> by the BIOS, and FreeBSD's wd driver does so, modulo bugs.

I think the complaint on that was that there are "wasted cylinders".  I
know this is true for ESDI drives, which are WD interfaced the same as
MFM or RLL.  That's why I suggested the cylinder range search in those
cases.

> >> >The disktab should go.
> >> 
> >> I see that you have sold your stock of ESDI drives :-).
> 
> >No, but I see that the slice code forces a translated world view
> >(fake cylinder boundries) on me pretty much anyway, unless I go
> >to an extrordinary amount of effort.
> 
> You shouldn't have sold your stock of optical attachments 8-).
> The slice only advises about the geometry.  The translated world
> view is encouraged by sysinstall's default partitioning scheme
> and the requirement to boot using the BIOS.

I still can't install on a WD1007 with sector sparing enabled, and
it's because of the translation assumptions.  8-(.  I would prefer
that, at the very least, the "preferred geometry" comes back on a
per controller basis because of this.  At the most, the geometry
information should be completely abstracted (like I've been
suggesting).

I'm going to take a shot at a non-functional "tool" prototype some
time in the next week or two to see if I can resolve the GUI/tool
communication issues.  If I can, expect me to lobby harder for the
abstration and the death of the disktab.  8-).


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.



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