Legacy BIOS Interrupt 13h Drive Numbering

I've been searching for drive numbering in legacy BIOS interrupt 13h for a couple of days when I finally stumbled on this Microsoft documentation: http://support.microsoft.com/kb/62571

This is the relevant excerpt:

The BIOS Interrupt 13H uses a zero-based number for floppy disk drives ("A"= 0, "B"= 1, and so on), and a zero-based number with the high bit (bit 7) set for hard disks ("C"= 80H, "D"= 81H, and so on).

Well, this info might have some use afterall ;-)