| 摘要 |
PURPOSE: A method for controlling a stable unlatch of an HDD(Hard Disk Drive) is provided to feed back head speed and to control an unlatch speed reduction current, so as to perform a stable unlatch operation. CONSTITUTION: An HDD(Hard Disk Drive) applies a forward constant unlatch current of a constant time to an actuator mounting a head, and accelerates a head speed, for a head unlatch(100). The HDD applies a backward constant unlatch current to the actuator during a preset unit time interval only, for a head speed reduction control, and initially-reduces the head speed(103). The HDD periodically searches servo information recorded in a disk(104), and detects information relating to each track within the servo information, then finds the head speed by the information(108). If the head speed is over a preset head speed threshold, the HDD gradually reduces the backward constant unlatch current as much as a preset brake current value, and applies the reduced current to the actuator(114). If the information relating to each track is not detected during the preset speed reduction interval, the HDD searches the servo information in a polling time interval(122). If a servo information synchronizing is not performed in the servo information search of the polling time interval(124), the HDD re-attempts the head unlatch(128).
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