According to an embodiment of the present invention, a data storage device comprising a motor having a stator is disclosed. Magnification varying is performed by varying the distances between the lens units by moving the lens units along the optical axis. In one exemplary implementation, an automated test system includes a plurality of test instruments, a switched event bus, and a test controller component. Z0 having a most significant bit ZM and a plurality of less significant bits ZM\u22121 through Z0 by a divisor RZN. The cover is configured to be removable attached to the housing and defines a button slot therein.