CONST IOERR_OPENFAIL=-1,
		IOERR_ABORTED=-2,
		IOERR_NOCMD=-3,
		IOERR_BADLENGTH=-4,
		IOERR_BADADDRESS=-5,
		IOERR_UNITBUSY=-6,
		IOERR_SELFTEST=-7,
		ERR_OPENDEVICE=-1
