Did you use the same
/boot partition for FC5 and CentOS? If you used different ones, you may have two partitions with the same
/boot label, and this can cause one to be invisible from the other.
What I suspect happened is that CentOS created its own
/boot, and changed GRUB so it points to that partition -- which has no information in it about FC5.
Here's what my
/boot/grub/grub.conf file looks like:
Code:
default=0
timeout=5
splashimage=(hd1,1)/grub/splash.xpm.gz
title Fedora Core 5 (2.6.16-1.2122)
root (hd1,1)
kernel /vmlinuz-2.6.16-1.2122_FC5smp ro root=/dev/FC5/Root rhgb quiet
initrd /initrd-2.6.16-1.2122_FC5smp.img
title Fedora Core 4 (2.6.16-1.2111)
root (hd1,1)
kernel /vmlinuz-2.6.16-1.2111_FC4smp ro root=/dev/FC4/root rhgb quiet
initrd /initrd-2.6.16-1.2111_FC4smp.img
title Fedora Core 3 (2.6.12-1.1381)
root (hd4,0)
kernel /vmlinuz-2.6.12-1.1381_FC3smp ro root=LABEL=/ rhgb quiet
initrd /initrd-2.6.12-1.1381_FC3smp.img
title Debian 2.6.8
root (hd7,0)
kernel (hd7,0)/vmlinuz ro root=LABEL=/ rhgb quiet
initrd (hd7,0)/initrd.img
title WinXP
rootnoverify (hd0,0)
chainloader +1
title SBootMgr
root (hd1,1)
kernel /memdisk.bin
initrd /sbootmgr.dsk
Notice particularly the
Debian entry, which is set to boot from a USB drive. The three lines tell GRUB:
1) Use drive 8, partition 1
2) Load the kernel from the specified file on (hd7,0)
3) Load the initial ram disk from the specified file on (hd7,0)
Now, in your case, you need to identify the HD and partition containing your FC5. The easiest way is to do a
fdisk -l (as root) after you start CentOS. (Remember, GRUB counts everting from 0, so, for example, /dev/hda3 would be (hd0,2) to GRUB.)
After you've found your various partitions, edit
/boot/grub/grub.conf (or, perhaps CentOS uses
/boot/menu.lst or even
/etc/menu.lst) so it has an entry referencing the FC5 installation following the
Debian model I showed you above.
If you have a floppy drive, consider creating a GRUB bootable floppy to experiment with. (Instruction can be found in
info grub.)
Good luck.
