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From: agc@uts.amdahl.com (Alistair G. Crooks)
Newsgroups: comp.os.386bsd.bugs
Subject: Re: bad144 problem?
Message-ID: <f1Io03hUd8E400@amdahl.uts.amdahl.com>
Date: 20 Aug 93 12:20:11 GMT
References: <9322908.27770@mulga.cs.mu.OZ.AU> <1993Aug16.180751.16931@crash> <9323215.4533@mulga.cs.mu.OZ.AU>
Organization: Amdahl Corporation, Sunnyvale CA
Lines: 42

In article <9323215.4533@mulga.cs.mu.OZ.AU> janj@acci.com.au writes:
>1) IPL is an IBM term for boot if you like.
>
>2) The bad sector table must be enabled by the badsect flag in the 
>	 disklabel.  To set this you issue 'disklabel -e wd0' and append
>	 badsect to the line with something like 'flags:' on it.
>
>3) I have had problems where bad144 did not write the bad sector
>	 table in the same location as wd.c did expect it to be when 
>	 the badsect flag was set in the disklabel.  The result was 
>	 a non-bootable... system.  This was fixed by modifying the 
>	 size of the 'c' partition.  It seems that if you run 386bsd
>	 from a 'fdisk' type partition rather than a whole disk, then
>	 the bad sector table is located on the last track of the 'c'
>	 partition.  However if your disk is a 'real' 386bsd disk then
>	 it will be allocated on the last track.
>
>4) I have also had a problem with using disklabel on a newly 
>	 lowlevel formatted disk.  There seems to be a bug which prevents
>	 you from using disklabel because it can not read the label...

All OK up to here.

>5) All this works for disks > 1023 cylinders.  The only thing that
>	 has to reside within that is wdboot because that is loaded by
>	 the bios. 

This is incorrect for NetBSD 0.8 - I'm not sure about 386bsd, it's
been a long time.  The reason for this is that the BIOS is used to
read the bad sector table during the NetBSD boot process, and the BIOS
maxes out at 1023 cylinders.  (During boot, if you get the message
"Bad badsect table" displayed, you've got this problem.)

I've talked to various others about changing this, and as soon as I
get some working hardware and some time together, I'm going to make a
stab at it. (Just in case anyone thought I was Monroying...)

Alistair
--
Alistair G. Crooks (agc@uts.amdahl.com)			     +44 252 346377
Amdahl European HQ, Dogmersfield Park, Hartley Wintney, Hants RG27 8TE, UK.
[These are only my opinions, and certainly not those of Amdahl Corporation]