On Tue, Nov 28, 2006 at 04:18:53PM -0800, K WESTERBACK wrote:
> I've booted OpenBSD from above cylinder 1024 (at least >8G) as far as I
> recall. However you *cannot* boot it from an extended partition w/o
> assistance of some kind. It's unclear from your email if this is what you
> attempted or not. Extended partition booting is an area of interest
> without firm target dates as yet.
It's a primary partition in both cases.
Machine 1: HP/Compaq desktop. I'm not in front of it right now; from memory
I think it's a model 2100. It's a 2.8GHz P4, so not too ancient.
# fdisk wd0
Disk: wd0 geometry: 4865/255/63 [78156225 Sectors]
Offset: 0 Signature: 0xAA55
Starting Ending LBA Info:
#: id C H S - C H S [ start: size ]
------------------------------------------------------------------------
0: A5 0 1 1 - 2609 254 63 [ 63: 41929587 ] FreeBSD
*1: A6 2610 0 1 - 4864 254 63 [ 41929650: 36226575 ] OpenBSD
2: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused
3: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused
#0 is FreeBSD 6.1, #1 is OpenBSD 4.0. I created the OpenBSD partition using
openbsd's fdisk.
The MBR contains the FreeBSD bootloader. At startup, the machine displays
F1 FreeBSD
F2 BSD
But when I press F2 I just get a beep. I boot this machine using cd40.iso
and typing "boot hd0a:/bsd"
Machine 2: Dell X1 laptop
My apologies, this was a false alarm. It turns out this *does* boot into
OpenBSD when I edit /etc/grub.conf appropriately.
For comparison purposes, it looks like this:
# fdisk wd0
Disk: wd0 geometry: 7296/255/63 [117210240 Sectors]
Offset: 0 Signature: 0xAA55
Starting Ending LBA Info:
#: id C H S - C H S [ start: size ]
------------------------------------------------------------------------
0: DE 0 1 1 - 10 254 63 [ 63: 176652 ] Dell Maint
1: 07 11 0 1 - 1968 254 63 [ 176715: 31455270 ] HPFS/QNX/AUX
2: 83 1969 0 1 - 5337 254 63 [ 31631985: 54122985 ] Linux files*
*3: A6 5338 0 1 - 7295 254 63 [ 85754970: 31455270 ] OpenBSD
#1 is Windows XP, #2 is CentOS 4.4, #3 is OpenBSD 4.0.
So maybe the problem with the desktop is an old BIOS, or a problem with
FreeBSD's bootloader.
As for why I thought that OpenBSD wouldn't boot above cylinder 1024, I
googled around and found a number of (probably old) documents about
dual-booting OpenBSD saying this was a problem(*). I would have taken these
with a pinch of salt, but the file INSTALL.i386 supplied with OpenBSD 4.0
also says:
"you MUST
BE SURE that all partitions which you want to boot from must start and end
below cylinder 1024 by the BIOS's idea of the disk, and that all DOS
partitions MUST EXIST ENTIRELY BELOW cylinder 1024, or you will either not
be able to boot OpenBSD, not be able to boot DOS, or you may experience
data loss or filesystem corruption."
The 1024 cylinder limit implies that OpenBSD must reside within the first
1024 x 255 x 63 x 512 =~ 8GB of the disk.
Having said that, it later says:
"The OpenBSD root partition must also reside completely within the BIOS
supported part of the hard disk -- this would typically be 504MB, 2GB,
8GB or 128GB, depending upon the age of the machine and its BIOS."
which implies it should work above 8GB with a modern BIOS.
Regards,
Brian.
(*) Such as:
http://geodsoft.com/howto/dualboot/openbsd.htm
http://www.packetwatch.net/documents/guides/misc/multi-boot.php
