Subject: Re: unbootable new disk?
To: Steven M. Bellovin <>
From: David Laight <>
List: current-users
Date: 11/27/2004 21:02:35
> Right -- and now that I have it working, I'm quite certain that the 
> problem is the 137G boundary.  (The disk has a jumper to limit it to 
> 32G -- which isn't what I bought a 160G drive for...)  

The 32G boundary is quite a common bios bug - 2^16 sectors.

> I have two questions now.  The first is whether or not some part of 
> NetBSD -- sysinst, fdisk, installboot -- should detect the problem and 
> issue a warning mesage.

Probably - buy me a big disk (and a system to put it in) and I'll
do the tests.

Seriously, part of the problem is having test systems that exhibit all
the random behaviour of broken BIOS.
sysinst has a means of restricting root to the start of the disk
(and having a small root and and large /usr) but that wouldn't be right
in this case - where it would be better to leave some free space.

> To me, the clue is the differing numbers of sectors reported by
> NetBSD and the BIOS.

I can change sysinst to detect that, and act on it.  But it does get
hard because some BIOS just lie......

> The second is what I should 
> do now: should I try a BIOS update, or should I just repartition the 
> disk so that wd0a is within the 137G limit?

You are ok provided /boot and /netbsd reside in the bottom 137G.
Why the system wasn't booting at all is a different problem.

> (Actually, the INSTALL 
> documentation should warn of this, too, and suggest that the default 
> partitioning -- everything in 'a' -- is a bad idea if you see the 
> warning about the BIOS versus your disks....)

Is there a warning about the geometry/size mismatch?
I've a system where the bios doesn't do LBA at all - but nothing to
try very big didks on.


David Laight: