INT 13,15 - Read DASD Type (XT BIOS from 1/10/86 & newer)

	AH = 15h
	DL = drive number (0=A:, 1=2nd floppy, 80h=drive 0, 81h=drive 1)


	on return:
	AH = 00 drive not present
	   = 01 diskette, no change detection present
	   = 02 diskette, change detection present
	   = 03 fixed disk present
	CX:DX = number of fixed disk sectors; if 3 is returned in AH
	CF = 0 if successful
	   = 1 if error


	- XT's must have a BIOS date 1/10/86 or newer
	- used to determine if INT 13,16 can detect disk change

	- see	INT 13,STATUS