Dynamic magnetic information storage or retrieval – General recording or reproducing – Specifics of the amplifier
Reexamination Certificate
2011-04-26
2011-04-26
Tzeng, Fred (Department: 2627)
Dynamic magnetic information storage or retrieval
General recording or reproducing
Specifics of the amplifier
Reexamination Certificate
active
07933090
ABSTRACT:
A disk drive is disclosed comprising control circuitry operable to calibrate a write current parameter. A write current is initialized to an initial write current INIT_Iw, and an overshoot is initialized to a maximum MAX_OS. The write current is swept from INIT_Iw to a maximum write current MAX_Iw while writing and reading data from a target track to measure a first quality metric. A second quality metric associated with wide track erasure is also measured. A quality of the write operations is determined in response to the first and second quality metrics. When the quality of the write operations does not exceed a threshold, at least one of the MAX_Iw and MAX_OS is decreased and the process is repeated. Otherwise, the write current is swept from a minimum write current limit MAX_Iw to the adjusted MAX_Iw for a plurality of tracks to find an optimal write current for each track.
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Jung Kameron Kam-Wai
Kwan Stephany W.
Tzeng Fred
Western Digital Technologies Inc.
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