http://grub4dos.sourceforge.net/wiki/index.php/Grub4dos_tutorial
CDROM related subjects
Using ATAPI CDROM in GRUB for DOS
Use the following command to initialize ATAPI CDROM:
cdrom --init
Then, use the following command to start using ATATPI CDROM:
cdrom --hook
After cdrom --hook, the CDROM device can be accessed using (cd0), (cd1), etc.
To boot from the first CDROM, use the following commands:
chainloader (cd0)
boot
To stop using CDROM:
map --unhook
cdrom --stop
The first command removes the (cdN) device mapping, while the second one stops the CDROM driver.
Note: If you boot GRUB for DOS from CDROM, the booting device will be (cd). This device is always accessible. However, if you want to access file from other CDROMs, you still need to initialize them using the above commands.
Examples:
To boot from the first CDROM:
title Boot From First CDROM
cdrom --init
map --hook
chainloader (cd0)
boot
