On 8/10/06, Nick Holland <[EMAIL PROTECTED]> wrote:
(sorry for the dup, Gustavo, I should have sent that to the list... -N.)
Gustavo Rios wrote:
> Dear fellows,
>
> i have two disks, my first disk (wd0) is running XP, my second (wd1)
> is running openbsd 3.9.
> In order to boot openbsd from windows boot manager, i did the following:
>
> $ dd if=/dev/rwd1a of=obsd.pbr bs=512 count=1
> /* copied to windows c:\ and added the following line on boot.ini */
>
> c:\obsd.pbr="OpenBSD"
>
> When i turn on the machine, i just get the selection screen. After
> selecting openbsd, nothing is showed. The screen is totally black with
> a blink cursor on top left corner.
>
> Does anybody have any ideia why it does not work.
>
> PS: Initially i believed it was because of XP and OBSD are on
> different HD, is it any sense?
>
> Thanks in advance.
>
http://www.openbsd.org/faq/faq4.html#Multibooting
First paragraph of that section is not taken seriously by too many people.
Last paragraph of the NTLDR section is also of interest to you.
That is:
"Note: The Windows NT/2000/XP boot loader is only capable of booting
OSs from the primary hard drive. You can not use it to load OpenBSD
from the second drive on a system."
I was preparing a response before I decided to check that, and this
just confirmed what I've learned intuitively.
The computer is turned and and jumps into the start of the BIOS. The
BIOS does it's checks and does a jump to the start of it's
bootdisk.The MBR code figures out where to go next (in the case of
harddisks it jumps to the start of a partition which should contain
the PBR). The NTLDR is the windows PBR (or perhaps it's a larger piece
of code that the actual windows PBR bootstraps, I don't know
specifics). So by the time the NTLDR is running it is already inside
the disk, and the references that are hardcoded into the OpenBSD PBR
of where to jump to find /boot _do not work_. They are based relative
to the start of wd1, not wd0, and trying them on wd0 means you are
jumping into random data.
Be glad you didn't accidentally hit something runnable and fry your circuits.
-Nick
