To map grub device names to linux device names in case of system containing IDE and SCSI storage devices. You can use device.map file with following format to let grub know the boot sequence:
(fd0) /dev/fd0
(hd0) /dev/hda
(hd1) /dev/hdb
(hd2) /dev/hdc
(hd3) /dev/hdd
(hd4) /dev/cciss/c0d0
(hd5) /dev/ida/c1d1# grub –device-map=/boot/grub/device.map
grub> root (hd0,0)grub> setup (hd0)