Source files are added in advance with data specification information necessary for conversion of the source files into a calibrating file, the source files are converted into a calibrating file, and calibration is performed based on the post-converted calibrating file. The oxide semiconductor film used for an active layer of the transistor is a highly purified and electrically i-type film which is formed by heat treatment through which an impurity such as hydrogen, moisture, a hydroxyl group or a hydride is removed and oxygen which is a main component of the oxide semiconductor and reduced together with the impurity removal step is supplied. In one implementation, the notification mechanism is a light emitting diode mounted externally on the handheld computing device. The boot and the receptacle have complimentary threads enabling the boot to be screwed into the receptacle.