Function 08h	Read Drive Parameters		  (XT, CONV, AT, XT/286, PS/2)
entry   AH      08h  
	DL      drive number (0-2) 
return  CF      set on error 
		AH      status code (see above) 
	BL      drive type (see AH=17h below) (AT/PS2 floppies only) 
	CH      maximum useable value for cylinder number 
	CL      maximum useable value for sector number or cylinder number  
	DH      maximum usable value for head number 
	DL      number of consecutive acknowledging drives (0-2) 
	ES:DI   drive parameter table