A method for providing a storage area network includes receiving, at a data storage node, data from a number of storage area network servers via associated local nodes coupled to a optical network. Each block has four faces and all four faces may generally have the same dimensions. Dual tone multi-frequency signals can be generated for selecting the at least one dual-tone multi-frequency selectable option associated with the user input. The subset of data includes at least part of the data elements of a data set. An inclination angle of the glass plate is set to an angle inclined 40\xb0 with respect to a horizontal line so as to be greater than a repose angle of the toner when the toner has poor fluidity under a condition of high temperature and high humidity.