Disclosed herein are disk drives and mobile host devices that include a resetable shock sensor. The arrangement includes, but is not limited to a concealable feature adapted to be mounted to an interior surface of a vehicle. Chart edges are derived chart edges from the sequence of input symbols in accordance with the set of finite-state automata and are stored in the parse chart. The rules are applied to the data units. Alternatively, the axial extension may be formed without barbs, the extension inserted into the rotor bore, and then the extension immobilized as by stamping of the barbs, tack welding, or the like.