Without options, map the drive from_drive to the drive to_drive.
This is necessary when you chain-load some operating systems, such as DOS,
if such an OS resides at a non-first drive. For convenience, any partition
suffix on the drive is ignored, so you can safely use ${root}
as a
drive specification.
With the -s option, perform the reverse mapping as well, swapping the two drives.
With the -l option, list the current mappings.
With the -r option, reset all mappings to the default values.
For example:
drivemap -s (hd0) (hd1)
NOTE: Only available on i386-pc.