| 摘要 |
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. The main amplifier can include a first frequency response effective for passing the main data elements, and the auxiliary amplifier can have a second frequency response for passing the auxiliary data elements while effectively blocking the main data elements. The main amplifier can have a first reference connection for balancing the main output relative to a data threshold, the auxiliary amplifier having a second reference connection effective for balancing the auxiliary output relative to a serial code threshold of the data head when the data head is reading auxiliary data elements. |
