An ignition coil apparatus for an internal combustion engine can suppress an increase in the manufacturing cost of a terminal of a low-tension side connector resulting from variation in a wire diameter of an one end of a primary winding, and can ensure a stable fusing state. The UDP multicast download progress notification system enables UDP messages to be sent only to registered clients, not broadcasted to all clients. A second embodiment of the invention involves a data processing system, including a primary error log to record an error, and at least one error logging register that can record information about the error. This achieves a low-impedance connection to the junction to be measured. In another aspect, the devices are enabled to connect over a wide area network and use the identifiers to obtain the music selection from a music distributor over the network.