A component for restricting relative movement of a rotor and a shaft is disclosed. According to the, present invention a client connected via a network is allowed to access the network storage devices as one virtual network storage system. The user input device may further include an optical tracking engine mounted in the housing proximate the substrate and being configured to transmit andor detect light for tracking movement of the user input device through the transparent portion of the substrate. The plurality of features each have at least one microscale dimension and at least one neighboring feature having a substantially different geometry. Spot welding on the substrate may also be used to adjust the alignment of the optical components.