Subject: Re: unbootable new disk?
To: David Laight <firstname.lastname@example.org>
From: Steven M. Bellovin <email@example.com>
Date: 11/28/2004 15:55:09
In message <20041127210235.GC1619@snowdrop.l8s.co.uk>, David Laight writes:
>> 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.
I had problems trying to update my BIOS -- I couldn't get a floppy
drive to work on that machine -- so I repartitioned the disk to keep
/boot and /netbsd near the beginning. This machine runs -current; I
expect to have new kernels frequently...
And if I get a chance, I'll craft some warning text for INSTALL.
--Steve Bellovin, http://www.research.att.com/~smb