On a sales image displayed on a LCD of a vending machine, there are set multiple commodity sample display areas and a commodity information display area. The device includes a rotatable inversion drum made up of inner and outer drum subassemblies, which are selectively interconnected by means of lock pin cylinders. The mobile wireless device measures at least one received signal metric for each candidate wireless cell in the set of candidate wireless cells. When performing reference access of an uncopied area in the second logical disk, the corresponding area in the first logical disk is referenced. During rendering, the database is accessed to determine the memory location for blocks of data, and the blocks are retrieved from the memory locations for processing. Features include a unique vertex representation allowing the graphics pipeline to retain vertex state information and to mix indexed and direct vertex values and attributes; a projection matrix value set command; a display list call object command; and an embedded frame buffer clearset command.