A lock is provided for a vehicle having a door and a fixed part proximate the door. A gas generator is also located within the chamber and contains a stable combustible material which can be ignited by an ignitor triggered by a sensor. The bins to which data access write operations have not occurred can be initialized using a zeroing process. Since the frame rate of the main line image signal and that of the monitor image signal are independent of each other, shooting an image while varying the frame rate of the main line image signal allows a monitor image at an image shooting time to be displayed at a predetermined frame rate using the monitor image signal DVr. A method of treating headache is provided. Audio can be played back in stereo and multichannel formats from a conventional stereo signal on compact discs, FM radio, or other stereo or monaural delivery systems.