| 摘要 |
Methods are provided for overwriting data in a probe-based data storage device (1) wherein data is represented by the presence and absence of pits formed in a storage surface (4) by a probe of the device. Input data is first coded such that successive bits of a first value in the coded input data are separated by at least one bit of the other value. Overwrite data bits nu 0, nu 1, nu 2,..., are generated from the coded input data bits b0,b1,b2, ..., and the overwrite data bits nu 0, nu 1, nu 2,..., are then used to overwrite data on the storage surface (4). According to a first method, the overwrite data bits are generated such that, if a pit represents a bit of said first value in the data storage device (1) then nu i = bi-1 for i ≥ 1 and nu 0 has said first value, and if a pit represents a bit of said other value in the data storage device (1) then nu i = bi-1 for i ≥ 1 and nu 0 has said other value. According to a second method, the overwrite data bits are generated such that, if a pit represents a bit of said first value in the data storage device (1) then nu i = bi-1 (bi-2 + bi) for i ≥ 2, nu 0 has said first value and nu 1 = b0, and if a pit represents a bit of said other value in the data storage device (1) then nu i=(bi-1(bi-2+ bi)) for i ≥ 2, nu 0 has said other value and nu 1 = b0. With both methods, the result of the overwrite operation is to record either the coded input data b0,b1,b2,..., or its complement b0,b1,b2,..., depending on whether a pit represents a bit having the first value or a bit having the other value. This result is independent of the bit values of the data which is overwritten.≥ <IMAGE>
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