Seagate Technology Incorporated

SoonWah Leow

TeckKhoon Lim

KokHoe Chia

KokSeng Lim

ChewHoon Angie Neo

TienHiong Lee

In a pattern zero verification test, a data track of a disc drive is read. During the reading of the data track, on-the-fly counting of potential non-zero data bytes (potential count), sectors on which ECC correction has been performed (corrected sector count), and user data bytes on which ECC correction has been performed (corrected byte count) is performed. Next, various conditions of the potential, corrected sector, and corrected byte counts are checked to determine whether the data track includes only zero data bytes.

Disc drive pattern zero verification test

A recording surface is segmented into a plurality of radial zones each containing a plurality of concentric tracks on which data may be recorded. The recording surface is initially formatted with a data frequency for each zone such that all of the zones have substantially the same data density. The data frequency is reduced for a first zone whose error rate is initially less than the predetermined error rate so that the first zone exhibits an error rate meeting the predetermined error rate. The data frequency for a second zone whose data transfer error factor initially exceeds the predetermined error rate is increased to restore any loss of storage capacity of the recording surface due to the reduced data frequency in the first zone. As a result, the data density in the first zone is substantially less than a nominal data density and the data density in a second zone is substantially greater than the nominal data density. The data storage capacity of the recording surface is at least as great as a minimum data storage capacity.

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SoonWah Leow