Abstract: A mass storage drive removably supports a mass storage element and includes a data head having an output for reading tracks of main data elements. The data head, which can be an optical head, is movable in a predetermined auxiliary path relative to the substrate for scanning a unique machine-readable serial identifier in auxiliary data containing at least 200 bits of information in one or more tracks being exclusive of main data tracks. The mass storage drive includes a head circuit connected to the data head output and having a main amplifier with an output for signaling main data elements in response to the data head, the circuit having a separate auxiliary put for signaling the auxiliary data elements in response to the data head output. The head circuit can include an auxiliary amplifier for driving the auxiliary output.