[Discuss] More Grub installation tips for newbies

[John Blomfield]

Following on from the great tutorial from Joydeep Bakshi:

http://jbakshi.50webs.com/Linux_tutorial/GRUB/GNU%20GRUB%20simplified.html

are just a few more tips I was reminded of while partitioning my backup 
computer hard drive and installing Fedora 8 in one partition and Ubuntu 
in another.  As a Fedora freak I naturally installed Fedora 8 first, 
checked it was OK, installed some extra software and then installed 
Ubuntu.  To my surprise when I fired up my computer again I found that 
Ubuntu had replaced my nice Fedora Grub GUI with a cheap text imitation 
text screen!  Now Fedora always asks during installation, if you want 
Grub and if so which drive to install it in and where to overwrite the 
MBR (master boot record).  Now I may have been answering the call of 
nature at the time or something but I don't remember Ubuntu asking about 
Grub or if it did and I was not paying attention and it must have timed 
out on the option.  My problem was then to recover my nice Fedora GUI 
with the additional entries for Ubuntu.  The first issue to be aware of, 
see the above tutorial, is the way Grub specifies hard drives but also 
that Linux hard drive designations do not correspond to the order of 
partitions on the hard drive but rather the order in which they were 
created.  For instance, when I re-partitioned my hard drive I deleted 
some at the top of the drive and some at the bottom and left one 
partition in the middle untouched.  Then I created new partitions in the 
unallocated regions this resulted in the following order:
sda4, sda2, sda3, sda1 from cylinder 0 to the the end, instead of the 
orderly 1,2,3,4.  To further confuse the issue Ubuntu calls these hda4, 
hda2, hda3, hda1 and then Grub calls these (hd0, 3), (hd0,1), (hd0, 2), 
(hd0, 0). I would make a table but it doesn't look good if you are using 
text only email.

So now what to do about Grub!  The following is also useful if you have 
a dual boot already set up with MSWindows and then you re-install 
MSWindows, which overwrites your MBR including Grub. 
1. First reboot your computer using a Linux Rescue disc (you do know 
where it is don't you?) or sometimes the disc 1 of your distribution or 
perhaps a live CD.
2. I used my Fedora 7 rescue disc since I had not downloaded the Fedora 
8 version but I have now.
3. Once booted you are asked if you want to mount the Linux versions it 
has found and since it was a Fedora rescue disc it found the Fedora 
installation.  Then do this at the prompt:
    # chroot /mnt/sysimage   - this gives you access to your 
installation image, this name could be different with different 
distributions.
4. Then do the following:
    # login
     login: root
    passwd: ******
    # cd /boot
    /boot# grub
    grub > find /boot/grub/stage1
    "response in my case" (hd0, 2) (hd0, 3)
    -what this tells you is that stage1 of grub has been found in two 
partitions, one of which is the Fedora partition (hd0, 3) or sda4, and 
the other Ubuntu partition (hd0, 2) or hda3.  Now since I want the 
Fedora Grub, I type, ( note the > is the Grub prompt)
     > root (hd0, 3)
    > setup (hd0)
    > quit
This tells Grub that my Fedora "/" directory is on (hd0, 3) and my MBR 
is on hard drive hd0, that is sda or hda, put Grub found in the Fedora 
/boot directory in the MBR replacing the one put there by Ubuntu or in 
the case of a MSWindows, the one put there by Mr. Gates!  Not that I 
should put Ubuntu and Mr. Gates in the same category!  My final task was 
to cut and paste the boot text from the Ubuntu /boot/grub/menu.1st file 
for booting Ubuntu into the Fedora /boot/grub/menu.1st file, save and 
reboot. Eye candy heaven!

The package hwbrowser is quite a nice GUI listing what hard drives and 
partitions are in addition lots of other hardware details.

John Blomfield