Samsung Electronics Co., Ltd.

Yong-gwon Lee

Cheol-hoon Park

Sang-hoon Chu

Chul Wan Park

Kwang-jo Jung

A method of testing quality of a servo burst signal recorded on a hard disk drive and a recording medium adapted therefor, the hard disk drive including a plurality of sectors within one track and the burst signals for servo control recorded radially on each sector. The method includes: detecting peak positions at a radial position in which amplitudes of the recorded burst signals peak respectively on each track; comparing the detected peak positions of the burst signals on each track; detecting peak position error count, the peak position error count being a number of tracks in which offset of the detected peak positions exceed an offset limit within a predetermined number of tracks; and if the peak position error count exceeds the offset limit, determining a write quality of the servo burst signal to be low. A servo burst signal recorded with uniform intensity and a servo burst signal recorded with shift from normal position can be detected. Therefore, the quality of a servo burst signal can be managed efficiently.

Method of testing servo burst signals of hard disk drive and recording medium adapted therefor

For unlatching a head within a data storage device, such as a HDD (hard disc drive), a VCM (voice coil motor) amplifier with a switch is used for applying at least one cycle of an acceleration current pulse to a voice coil motor (VCM) for unlatching the head during an acceleration time zone. An analog to digital converter samples a characteristic of the VCM for indicating a speed of the head during the acceleration time zone. An unlatch controller terminates the acceleration time zone when the speed of the head is higher than a threshold speed, for more stable operation of the head but with guarantee of unlatching, regardless of the latch force within the HDD.

Apparatus and method for unlatching a head within a data storage device

A method and apparatus to compensate for a difference between an actual torque constant and a modeling torque constant used for servo design in a disc drive. The method has operations of: performing predetermined test seeks with respect to test seek positions into which a disc is divided; obtaining torque compensation constants from the test seeks; storing the torque compensation constants in a torque compensation constant table; and compensating for a gain of a seek control loop at a position where a seek is performed in a seek mode, using the torque compensation constants stored in the torque compensation constant table.

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Suwon-si, South Korea

Yong-gwon Lee