An apparatus, method and computer program product are provided for differentiating between and transmitting different levels of information associated with an object or file depending upon a number of tactile inputs detected. In one aspect, a hubless caster is provided that includes a frame member having two opposed sides. An occlusion height field is generated based on an orthographic height propagation of the perspective modulated height field. In a preferred embodiment, the outlet center has a plurality of power outlets and a plurality of communication outlets. Alternatively, the pump capacity is measured using an output flow efficiency ratio, which compares a theoretical pump flow at a given gear speed to the effective housing length of the pump.