From device.map
(fd0) /dev/fd0
(hd0) /dev/hda - PM
(hd1) /dev/hdb - PS
(hd2) /dev/hdc - SM
(hd3) /dev/sda - sata1
(hd4) /dev/sdb - sata2 - First boot disk, VISTA c:/ and wubi-ubuntu installed

grub4dos discovers hd4 as hd0