Abstract: In a computer system, a device for and a method of conducting self-diagnosis of failure such as a break and a short circuit of a data communication line remove difficulty of conducting the self-diagnosis of the break and the short circuit only by driving and monitoring the data communication line by itself. For this purpose, a diagnosis module receives information necessary for self-diagnosis from a monitoring module connected to the data communication line. The diagnosis module to conduct self-diagnosis is connected via a diagnosis communication line to the monitoring module to communicate diagnosis information between the modules.

Abstract: The electronic flash unit disclosed comprises: a transformer (14) to vary voltages of a power supply; an accumulator (16) composed of a main capacitor (17) to charge an electric energy supplied from the transformer (14); a lamp unit (4) provided with a flashlamp (20), set inside of a reflector (19), that flashes by discharging of energy storages in the main capacitor (17) upon applying a voltage on a trigger terminal (21); and a trigger circuit (10) to generate the voltage to apply on the trigger terminal (21), wherein at least the lamp unit (4) is coated with an insulation material.

Abstract: In order to vary a light emission angle, a light source is moved so that its position relative to a reflector is varied. In one mode, by compulsively moving the light source to one end of a movement range of the light source, the one end is set as an original position. In another mode, after the light source is compulsively moved to the one end, by detecting that the light source has reached a position preset in the movement range while the light source is being moved to the other end of the movement range, a distance by which the light source is moved from the one end to the preset position is detected and stored as control information. The subsequent operation to move the light source to a desired control position is controlled based on the original position which is the one end or based on the control information.