The present invention provides a data processing method for encrypting or decrypting contents data using contents key data. Heat transfer surfaces for transferring heat between air of the heat transfer tubes and the heat transfer fins have holes each having a radius smaller than the critical radius of a nucleus that occurs upon phase change from water vapor to condensed water droplets such that the holes are filled with the air at all times. The identification mark indicates that the storage medium is a write protected storage device. If the secondary spreader bar is attached near the trailing edge, optionally a tertiary spreader bar may be attached at the trailing edge to aid in the floatation of the entire sheet. A set order of communications occurs between a master node who won the contention and a slave node being communicated with by the master node to transfer a data frame.