Methods and apparatus, including computer program products, for deletion in data file forwarding framework. The comparator includes a gain stage and a bias stage. A video playback control apparatus selects trailers and commercials in accordance with information on the distributor of the movie, the star actoractress, the genre, etc. The element may be configured to restrain the object as the plurality of gripper fingers release the object. A liquid level control unit controls the liquid level within predetermined limits by controlling one or more components based on the output signals from the flow demand control unit, the shaping unit, and the third filtered output signal.