INT 13 - Compaq, ATAPI Removable Media Device - GET CURRENT MEDIA FORMAT

	AH = 20h
	DL = drive number (00h,01h)
Return: CF clear if successful
	    AL = media type (see #00265)
	    AH = 00h
	CF set on error
	    AH = error code
		01h invalid request
		30h drive does not support media sense
		31h no such drive / media not present
		32h non-default media / drive does not support media type
Notes:	this function is supported by the 1993/3/8 Compaq ROM BIOS, but only
	  partially (AL is always 00h when successful) by the 1993/8/3 version
	this function is also supported by some recent versions of the Phoenix
	  486 BIOS
	this function does not seem to be supported by some Toshiba BIOSes
	  (at least before 1995, maybe some laptops??? with 1.44 MB floppies),
	  because S/DOS 1.0 contains code to bypass a call to this function,
	  always assuming the drive would not support media sense.
SeeAlso: AH=15h