GRUB

•   GRUB - the Grand Unified Bootloader
• Command -line interface available at boot prompt
• Boot from ext2/ext3,ReiserFS,JFS, FAT,minix, or FFS filesystems
• supports MD5 password protection

• /boot/grub/grub.conf
• changes to grub.conf take effect immediately 
• If MBR on /dev/hda is corrupted, reinstall the first stage bootloader with

• /sbin/grub-install /dev/hda 

Here is  sample grub.conf

# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE:  You have a /boot partition.  This means that
#          all kernel and initrd paths are relative to /boot/, eg.
#          root (hd0,1)
#          kernel /vmlinuz-version ro root=/dev/hda3
#          initrd /initrd-version.img
#boot=/dev/hda2
default=0
timeout=10
splashimage=(hd0,1)/grub/splash.xpm.gz
title Red Hat Linux (2.4.7-10)
 root (hd0,1)
 kernel /vmlinuz-2.4.7-10 ro root=/dev/hda3 hdc=ide-scsi
 initrd /initrd-2.4.7-10.img
title Windows 2000
 rootnoverify (hd0,0)
 chainloader +1

GRUB reads the configuration file at boot time, so the grub.conf file must be stored on a filesystem GRUB understands. These include ext2/ext3, reiserfs, FAT, minix and FFS. If for some reason your MBR becomes corrupted and you need to reinstall GRUB, you can do so with the command  /sbin/grub-install .


example
# /sbin/grub-install /dev/hda   for hard disk.
# /sbin/grub-install /dev/sda  for Sata or Scsi




If grub-install fails for some reason try the following;

1. Type the command grub and press Enter
2. Type root (hd0,0)
3. Type setup (hd0)
4. Type quit

Restart the sytem  and  login.