Hard Drive to /dev mapping
 

Okay, I've actually searched google for the subject and everything that comes back, at least
on the first page, deals with adding a new hard drive, or partitioning a hard drive, and
essentially, not what I am actually looking for.

First off, my hardware setup:

Soyo KT333 Dragon ultra MB, AMD socket A
AMD Athlon XP 2000+, 512M RAM, sound, ethernet, other stuff as supported.
MB has 4 IDE channels, two regular ones, and two RAID channels.
Hard disk drives:
/dev/hda - Primary IDE channel Master, setup for Windows 98
/dev/hdb - Primary IDE channel Slave, setup for Multiple Linux distros
/dev/hdc and /dev/hdd are DVD+/-RW drives, Secondary IDE channel, master and slave
/dev/hde - one partition for windows and the bulk for Linux, RAID Primary Channel Master
/dev/hdf - strictly linux., RAID Primary Channel Slave

Now, my current setup is running Slackware 10.1 and Win 98SE dual boot but I wish to give
SuSE 10.0 a try so I downloaded the DVD and booted it up to install it in an empty partition
on /dev/hdb. Everything was going fine till I got to the point of being asked where to install
it to when the "problem" arrises.

Apparently SuSE thinks that my mapping is such that the RAID controller IDE channels
should be /dev/hda through /dev/hdd, and the normal IDE channels are /dev/hde through
/dev/hdh as so:

MB/Win98/Slackware Suse
/dev/hda --> /dev/hde
/dev/hdb --> /dev/hdf
/dev/hdc --> /dev/hdg
/dev/hdd --> /dev/hdh
/dev/hde --> /dev/hda
/dev/hdf --> /dev/hdb

If I tell the installer to use /dev/hdf?, this being the actual physical partition
where I want it, and grub to be installed on this partition, it does install fine. Next I go into
my currently existing grub menu and add the SuSE partition to it, no matter what I choose
for SuSEs root partition, SuSE dies with the kernel error about not being able to mount it's
root file system. It turns out that this HDD to /dev/hd? mapping change isn't actually
specific to SuSE but also occurs with an older version of Linux From Scratch, and the Helix
V1.6 CDROM ISO that I just downloaded.

So, the question is: what is causing the swapped device mapping that SuSE sees when the
system MB and the other OSes see the normal setup? Personally, I believe it is something
specific to the kernel/auto-hardware-detect sequence but I'm not sure what, or where to
look as I've never encountered the problem before.

Rick.

I'f have thought that you would be able to get Suse to install it's bootloader on
the partition it's installed to (hdb to you, hdf to Suse), and then chainload that
bootloader from your original.
see:
http://www.linuxquestions.org/questi...hreadid=376498
This would be my personal preference.

Alternatively you might be able to map the drives before booting the Suse kernel:
eg:
map (hd0,1) (hd0,5)
map (hd0,5) (hd0,1)
in your grub.conf might do the trick.

Well I figured since I'm already using GRUB to begin with (very nice boot loader) that I would be able to just install SUSE
to the empty partition, then add and entry in my current menu.lst file to be able to boot it. The problem there is that it
would find and boot the kernel, but then the kernel wouldn't be able to mount its root file system as it couldn't find it on
the partition specified, and I tried telling it the paritition names both ways.

I'll check out the mapping you specified to see if it works.

(As and aside, I tried to again install SUSE and while it did install and run, it killed my Slackware partition causing it to
have the same kernel panic error about not finding its root file system. As such, I don't really think the problem is unique
to SUSE [as I previously mentioned], but I'm beginning to think that it has to do with grub. I ended up having to install
lilo to get slackware to boot, then reinstalling grub to get back to my original setup. As such I'm beginning to think it's a grub problem, or lack of knowledge about grub from my part. Time to do some more reading on grub I guess.)

Thanks for the info,
Rick

I strongly suggest chainloading.

Okay, a follow up of my results:

Yes, I finally did get the system to boot after some rearrangement of the hard drive (again) and
a reinstall of SuSE. However, chainloading wouldn't work (don't know why, probably just a simple
partition selection choice). What did work was the following grub entry in my original grub
installation (this was taken from the menu.lst file from the SuSE install and then the map
commands were added and the root line modified so the original grub could find the kernel
desired):

title SuSE 10.0
map (hd1) (hd5)
map (hd5) (hd1)
root (hd1,6)
kernel /boot/vmlinuz .....

Note that the "root" command still refers to the partition in terms of the original grub installation,
not from the point of view of the SuSE kernel, but the root= parameter given to the SuSE kernel in
the original kernel line refers to the partition from the SuSE kernel point of view.

I was able to finish my setup and start running SuSE without any other problems.

Thanks for the help.

Rick