Function 15h	Get Disk Type				     (except PC and XT)
entry   AH      15h 
	DL      drive ID 
return  AH      disk type 
		00h     no drive is present 
		01h     diskette, no change detection present 
		02h     diskette, change detection present 
		03h     fixed disk 
        CX:DX   number of 512-byte sectors when AH = 03h