Thanks to all for the advice and knowledge you shared about how
grub works. I am writing this on June 6 and early this morning,
I edited the boot command in the grub shell after
verifying that my stubborn no-boot drive truly was sitting at
hd0,1msdos and grub-install had picked out hd2,1msdos for every
single drive reference, even the bare metal one.
I did try that one first in case I was missing some magic
but the only drive on the whole system was that one and listing
the contents of (hd0,1msdos) show exactly what you see if looking
at / so grub showed it exactly where one would expect it to be
and hd2,msdos is pure science fiction on that system so I set
every drive reference to hd0,1msdos except the root which grub
wanted to set to /dev/sdc1.
The sample that Greg Wooledge showed looked very close to
how my grub.cfg looked after doctoring the drive references to
point to hd0,1msdos. and I tried booting that way and set the
root parameter to /dev/sda1, /dev/sdb1 and /dev/sdc1 which is the
one that grub chose, again non-existent. /dev/sdb1 is actually a
Zipdisk drive but I tried it anyway since there is no zipdisk in
there.
It never booted so I am throwing in the towel, figuring
that in all the messing around, I have corrupted something and
wasted about two weeks on and off trying this, that and the other.
I have a good 32 GB drive left over from a computer that
died last year so I will just clone it from the working system
that is sending this email. The drive that can't boot but is
otherwise fine will now be the second drive and will mount as
/home where all the important stuff I used it for can still live.
The only good thing about this exercise is that I know a
lot more about what grub does than I did and I also discovered
that while I had perfect backups of the home directory, I had
failed to set rsnapshot to backup /boot which was quite a stupid
oversight on my part. /var, /etc and several other directories off of
/ get daily backups and I could have sworn /boot did but it's not
there so I have been doing a lot of industrial-grade swearing
lately.
Grub is a very fine tool when used properly and I do
believe that there should be a pristine way to make a disk
bootable that is intuitive and automatic plus unaffected by the
configuration of any other drive on the system, like the old sys
command in DOS to make any DOS diskette bootable.
The unix incarnation of the sys command would have to do
a lot more such as verify that you have a kernel and modules
ready to go plus consult your /etc/fstab and /etc/default/grub
files but that shouldn't be a real problem. One would basically
do the grub install in a a total jail so it would come out set as
if one had just been running the installer and this was the only
drive on the system.
Thank you all for your help and sorry that it took so
long to determine that nothing simple was going to work.
Martin
