A calendar mechanism-equipped timepiece having a compactly constructed drive mechanism for driving first and second date indicators is offered. A waveform data compressing portion compresses a given data amount of original waveform data according to the selected trial mode so as to generate the residue code, the data amount being determined in correspondence with the selected trial mode. In addition to known identification functions, the identification system may perform additional important functions without requiring any significant additional expense. The tank extends from a lower portion to an upper portion to contain fluid therein. Temperature, occupancy and other sensors can be incorporated.