Hi!
Thank you for your answer but let me put more clearly the question i had.
I have two fdisk partitions, this disk has quite ugly layout but i just
tried things out (it had at times four OpenBSD instances :)
# fdisk sd0
Disk: sd0 geometry: 1044/255/63 [16777216 Sectors]
Offset: 0 Signature: 0xAA55
Starting Ending LBA Info:
#: id C H S - C H S [ start: size ]
------------------------------------------------------------------------
*0: A6 0 1 1 - 261 22 16 [ 63: 4194304 ]
OpenBSD
1: B6 0 0 1 - 267349 89 4 [ 0: 0 ]
<Unknown ID>
2: B6 0 0 1 - 267349 89 4 [ 0: 0 ]
<Unknown ID>
3: A6 783 64 49 - 1043 254 63 [ 12582975: 4188885 ]
OpenBSD
/grub/menu.lst is in 3rd fdisk partition's partition 'a'.
Everything works allright and my question is that is it possible while
booted up with kernel and root filesystem form 0rd fdisk partition to
access 3rd fdisk's 'a' partition?
Imre
Louis V. Lambrecht wrote:
Imre Oolberg wrote:
Hallo!
I experimented with OpenBSD 4.2 on i386 platform, made two fdisk
partitions on the same disk, into each of them OpenBSD disklabel,
installed grub from packages and can successfully dualboot.
But i cant figure out if there is a way to access fdisk partition's
disklabel partitions while booted up from the other fdisk partition's
OpenBSD instance? Ie it seems, that either way e.g. wd0a is a root
partition and there isnt a way to point to non-booted-up disklabel's
root partition.
It doesnt practically impact my use of OpenBSD (workaround could be
using two physical disks, for example) but its interesting to know if
it is so.
Imre
PS In /usr/local/share/doc/grub/README.OpenBSD is an hint actually on
this
...
When booting, the kernel will use the disklabel from the first OpenBSD
partition found, therefor grub has to set the partition type of unused
partitions to another value as can be seen in
/usr/local/share/examples/grub/menu.lst.
Louis V. Lambrecht wrote:
>> ....
My way is to use grub.
Has to do with the way OpenBSD default label reads and allocates the
labels in it's default install.
(I never could edit a disklabel correctly).
What I do is to partition the disk to have a second OpenBSD disklabel.
Also, I have my sources and packages(/usr/ports) on yet another slice.
Grub allows me to mark the operating system.
So, a normal entry for OpenBSD would look like
title openbsd_working
root (hd0,1)
chainloader +1
Which I can change for
title openbsd_testing
parttype (hd0,1) 0xB6
parttype (hd0,2) 0xA6
root (hd0,2)
chainloader +1
Uff course, must change amd revert the working instance to:
title openbsd_working
parttype (hd0,1) 0xA6
parttype (hd0,2) 0xB6
root (hd0,2)
chainloader +1
Grub let me hide or unhide partitions (which can be usefull if you
try to install an OS
via Anaconda (RedHats and derivates) which read the 0xA6 to be
"active" ad bortk out.
Will try the hide/unhide method on next fresh install.
Found this method straightforward, foolproof, and not needing to
write any wrappers.
I see I was incomplete in my former mail: indeed you need to boot GRUB
from wd0a,
or ...
put GRUB in another partition.
Actually, I have a Debian Linux in an "extended partition" which holds
the GRUB.
Always nice to have a Linux around with FFS, UFS and Sun modules and be
able to,
at least read, *any* filesystem.
