Old /boot, Grub, FC3

[Mikkel L. Ellertson]

Nick Geovanis <n-geovanis at northwestern.edu> wrote:
>>Date: Mon, 23 Jan 2006 12:55:57 -0600
>>From: "Mikkel L. Ellertson" <mikkel at infinity-ltd.com>
>>Subject: Re: Old /boot, Grub, FC3
>>Message-ID: <43D526BD.40502 at infinity-ltd.com>
>>
>>Nick Geovanis <n-geovanis at northwestern.edu> wrote:
>>
>>>Have an HP Pavilion 6630 (old, 500MHz), it has a two-channel IDE
>>>controller. FC3 is already installed on channel A, which it calls ide0,
>>>with a WD drive as master and an older Samsung CD drive as slave. IDE
>>>channel B is empty. I want some extra disk space, so I put a former FC3
>>>boot/root/installation drive on channel B to build new filesystems;
>>>nothing on it I want to save. Rebooting the machine, Grub chokes when it
>>>finds the old partition labelled /boot on the newly-installed drive cabled
>>>to channel B. The logs show that FC3 booted and configured both IDE
>>>channels as ide0 and ide1, and found all three drives, but then it got
>>>confused and tried to mount non-existent partitions, ended-up losing /usr,
>>>
>>
>>A couple of points here. First of all, it is not Grub that is having
>>the problem. All Grub does is load the kernel, and the initial RAM
>>disk. After that, the kernel takes over, and mounts the root file
>>.... 
> 
> 
> But it may be that the "wrong" kernel was booted, namely the one on the
> older but newly installed drive on ide1/channel B. It had once been a
> full boot/root/user-flesystems drive for FC3. Understand that the BIOS
> setup screens on this motherboard do not permit one to distinguish between
> multiple, internal IDE disk-drives. You can choose USB boot, CDROM boot,
> removable media boot, "internal hard-drive" boot; but you can't make a
> choice from among the latter.
> 
Nope - That is why the drives are specified in the Grub config file
with ether the drive number, or the device. As long as the same
drive is still on /dev/hda, Grub will boot the same kernel.
> 
>>Now, you can not directly tell the system to ignore the file systems
>>on the new drive without disabling the drive all together.
> 
> 
> Disagree. I made no new entries in /etc/fstab to mount the second,
> newly-installed drive's partitions. Therefore they should have been
> ignored. So it seems that there are only two possibilites: (1) The 
> correct drive was booted (channel A/ide0 master) but the wrong
> partitions were found at mount time; or (2) The incorrect drive was 
> booted (channel B/ide1 master) and, again, the wrong partitions were
> selected for mounting.
> 
Look at /etc/fstab - are the partitions specified as
/dev/<something>, or are you using partition labels? If you use
 partition labels, and you have more then one partition with the
same label, you get unpredictable results.

> Or is it possible that Grub (or the BIOS?) only want one IDE master over
> the whole dual-channel IDE controller? My understanding was that each
> channel needed its own master, and I've never had a problem before with
> DOS, Windo$e or linux in that situation.
> 
Nope - I have used systems with a master drive on each controller
many times. As long as I do not use partition labels, or I do not
have duplicate partition labels, things work fine.

Mikkel
-- 

  Do not meddle in the affairs of dragons,
for thou art crunchy and taste good with Ketchup!