Node:Device syntax, Next:File name syntax, Up:Filesystem
The device syntax is like this:
(device[,part-num][,bsd-subpart-letter])
[] means the parameter is optional. device should be
either fd or hd followed by a digit, like fd0.
But you can also set device to a hexadecimal or a decimal, which
is a BIOS drive number, so the following are equivalent:
(hd0) (0x80) (128)
part-num represents the partition number of device, starting
from zero for primary partitions and from four for extended partitions,
and bsd-subpart-letter represents the BSD disklabel subpartition,
such as a or e.
A shortcut for specifying BSD subpartitions is
(device,bsd-subpart-letter), in this case, GRUB
searches for the first PC partition containing a BSD disklabel, then
finds the subpartition bsd-subpart-letter. Here is an example:
(hd0,a)
The syntax like (hd0) represents using the entire disk (or the
MBR when installing GRUB), while the syntax like (hd0,0)
represents using the partition of the disk (or the boot sector of the
partition when installing GRUB).
If you enabled the network support, the special drive, (nd), is
also available. Before using the network drive, you must initialize the
network. See Network, for more information.