Subject: Re: sysinstall changes
To: Greg Hudson <ghudson@MIT.EDU>
From: None <>
List: tech-install
Date: 09/18/1998 07:56:17
Greg Hudson <ghudson@MIT.EDU> writes:

> wrote:
> > Point of clarification: The reason we round to BIOS partitions is to
> > live compatibly with other OS's on the disk.
> A fair bit of code out there assumes that BIOS partitions end at the
> end of a cylinder.  Some of it is even in the NetBSD kernel;
> arch/i386/i386/disksubr.c resets part of the geometry in the fake
> disklabel if it finds a NetBSD partition, with the assumption that it
> ends at the end of a cylinder.  (Granted, I'd like to see this code
I've always looked at this and said my god, they could just take the
geometry from what BIOS leaves in memory and yet they do this hack.
The funny thing, and I've not looked at the wd code for years, is that
you would think that they take this info and do a "setcontroller" with
it.  Well, last time I tried to do a setcontroller (under Mach) with 
a BIOS geommetry from an LBA configured disk (say C/H/S 1024/64/63 vs
a true geometry of 4096/16/63 (numbers sort of made up here)), the
controller hung.  So I don't believe we use these numbers for anything.

> excised, since it just causes trouble, but the i386 portmaster(s)
> didn't comment on my PR.)