A method for generating a drive signal for a micro-electro-mechanical system scanner is provided. Upon reaching or surpassing the memory resource threshold provided, the counter may indicate the need for garbage collection. The operator arm may define a gear. The variable pump stator blades are arranged radially outwardly of the pump rotor wheel. The a set of piston pumps includes at least two piston pumps of different models, and the pumping regions of all the piston pumps the set are embodied as structurally identical pumping modules.