There is disclosed an ink jet printhead which comprises a plurality of nozzles and one or more heater elements corresponding to each nozzle. The pre-pulsed magnetic field is used to control the amount of rotation in the state of polarization, and therefore, the ON-OFF extinction ratio. When the pusher shaft abuts the bone adjacent one of the open ends of the bone tunnel and the gauge member abuts the bone adjacent the other open end of the bone tunnel, an indicator mark on the pin can be visible through one or more windows formed in the gauge member. Storage capacity can be dynamically allocated between multiple namespaces by writing data to free blocks and updating the metadata accordingly.