Function  44h   I/O Control for Devices (IOCTL)  Get or Set Device Information

entry   AH      44h 

	AL	0Eh	Get Logical Device (DOS 3.3+)

			BL      drive number (0=default) 

			return  AL=0 block device has only one logical drive 

			        assigned 1..n the last letter used to reference 

			        the device (1=A:,etc)