INT 21,44,6 / IOCTL,6 - Get Input Status

	AH = 44h
	AL = 06
	BX = handle


	on return
	CF = 0 if successful
	   = 1 if error
	AX = error code if CF set  (see DOS ERROR CODES)
	AL = 00  if EOF (files), or not ready (char devices)
	   = FF  if not EOF (files), or ready (char devices)


	- used to determine if a file or device is ready for input
	- can be used to determine EOF unless EOF caused by INT 21,42