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Re: Installing Debian on second hard disk

Hello,
Thanks for your reply. I now see some possibility that it might work. However, for the problem you are facing, that even when you setup the second(slave ?) HDD as the first one in BIOS, that drive ends up as hdb instead of hda. That I think is because, Linux ignores the BIOS and finds out info about the disks on its own, so it knows that hd0 is not the first hard disk but the second one. I think windows 2000 also functions like this. So, I need to know whether your hard disk was hda or hdb at the time of installation of Debian. If the disk name changes will debian still boot or will it refuse to boot ? I want a separate grub on both hard disks and I will load the second grub from the first one when I want to boot an OS on the second disk, I will remap hd0 and hd1 to fake the BIOS change. Hope I can fool them ! Why don't you too try this out instead of making changes in BIOS everytime you want to boot from the second hard disk. Just write map (hd0) (hd1) and map (hd1) (hd0). This should swap your HDD's without making changes to the BIOS everytime. Then you load the grub on the second disk using chainloader just like we load windows bootloader. 
thanks a lot
Dhiraj


Rosenstrauch, David wrote:
If I add entries like (hd1,0) and (hd1,1), will the grub on my first disk be able to boot the win2K and Debian on the second HDD. I don't mind if it won't boot win2K but will atleast Debian 3.0r2 boot ? 


Short answer:  yes.  Grub on the first disk should be able to boot either of
the 2 OS's on the second disk.


I just went through this whole issue myself (trying to get 2 drives in my box
both able to be booted) which is how I know.  I set up my second drive as a
fail-safe:  I can always boot off that even if I mess up the first one.  All I
need to do now is go enter the Dell BIOS setup and switch the order of the
drives listed and that switches the machine to boot off the second drive.  In
other words, each drive can function as a stand-alone.  It's a complete
bootable system complete with its own grub installation.

In the above context, by the way, by "boot" I mean "run grub off of".

So you can config the 2 drives the way I have them.  Or you could have grub
only exist on 1 of the drives and always boot (run grub) off of that drive.
From that point on grub completely takes over, and you can instruct it which
drive and sector you want to load the kernel from (e.g., "root (hd0,0)" or
"root (hd1,0)"), which drive and sector contain the root file system (e.g.,
"vmlinuz root=/dev/hda1" or "vmlinuz root=/dev/hdb1"), etc.

So bottom line is that grub is completely configurable that way.


FYI - the only significant issue I had when setting it up my way is that when
I switch the order of the drives in the BIOS, I was surprised to find that the
drive that's first to boot winds up always being assigned (hd0) to grub, but
when the kernel finally loads it may turn out that that drive is actually
/dev/hdb.  This confused me for a while till I figured out what was going on,
as I assumed that grub's drive assignment should have matched the kernel's.

Hope this helps.  Email back if you need more clarification.


DR



-----Original Message-----
From: Dhiraj [mailto:dheerubhaipompom@yahoo.com]
Sent: Wednesday, January 28, 2004 3:18 PM
To: debian-user@lists.debian.org
Subject: Installing Debian on second hard disk


Hello,
My motherboard has two IDE channles. I have two optical drivers on one channel and my HDD on the second. I have win98SE and Red Hat 7.2 on my current HDD. I am planning to buy a second HDD and install win 2000 and Debian on it. When installing Debian 3.0r2 and win 2000, I would like to take out my first hard disk and put in the blank second one. This is because I am paranoid about something breaking the original hard disk(I spent a lot of time making many things work and installing stuff on my RHL). I fear that if not Debian, atleast win 2K will destroy my first hard disk somehow. Now, when I put in the second hard disk and the first is out, the second one will become /dev/hda but when I re-insert the first one as master, the second one will become /dev/hdb. I have grub as my loader on the first hard disk. If I add entries like (hd1,0) and (hd1,1), will the grub on my first disk be able to boot the win2K and Debian on the second HDD. I don't mind if it won't boot win2K but will atleast Debian 3.0r2 boot ? Or is it that since I installed on /dev/hda and now I put it in /dev/hdb the kernel will refuse to boot since it had hard references to /dev/hda ? If in the grub on the older disk I write map (hd0) (hd1) and map (hd1) (hd0) and then load grub again on the second disk(using chainloader) as another boot loader will it work. Will Debian and W2K be fooled into believing that they are on the first disk or do they ignore the bios and check out the HDD's on their own ? 
thanks a lot
Dhiraj



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