There are provided an information storage medium capable of real-time recordingplayback of digital moving picture information, and a digital information recordingplayback system using this medium. The liquid cooling system includes a cold plate having an inlet and an outlet to permit liquid to flow through the cold plate. A hook structure is coupled to the hanger body and formed for hanging of the hanger from a support device. When activated by its respective control signal, the connection circuit connects its associated adjustment circuit to the voltage divider circuit so that the reference voltage is generated by the voltage divider as adjusted by the connected adjustment circuit.