A self-powered computer-pointing device includes a housing and a roller ball accommodated within the housing. In this power-assisted supercharger, a turbo lag can be reduced by itself, power consumption can be small even in a range in which the rotational speed is high, malfunctions or unnecessary power consumption can be prevented, a control system can be simplified, and the installation space and the weight thereof can be small. A rendering flow for the compressed multimedia data according to the at least one performance parameter is then determined dynamically, wherein the rendering flow comprises a specific arrangement of rendering procedures indicating the execution order of the rendering procedures. The first high voltage level is higher than the second high voltage level, and a voltage applied on the selected wordline is negative within the second time interval. Deployment of the cushion pulls tape from the cartridge at a rate that is monitored by transmitting light through the tape, or by detecting the presence of metalized, or magnetic shielding portions, of the tape.