A system and method for updating one or more files on a computing device are provided. The apparatus includes pistons integrally formed in a diaphragm and coupled to the diaphragm by convolutes. When the result of comparison shows that the acceleration peak is higher than the threshold, the flow moves to step S7 to produce a safety signal. A method of fabricating the optical switch having an insulator is disclosed. The secret key changing unit changes a secret key used by the digital signature generating apparatus to a secret key specified by the first command, if the first command is received by the receiving unit. The temporary dilute surfactant water solution has a surface tension of not less than 50 dynescm.