Abstract: Embodiments in accordance with the present invention reduce the number of errors caused by the aged deterioration of a heater for adjusting the clearance between a head and a disk. According to one embodiment, a thermal fly height control (TFC) controller executes the measurement of a resistance value of a heater in a predetermined timing. The TFC controller judges whether or not the measured resistance value falls within a predetermined reference range. If the measured resistance value falls within the reference range, the processing ends without performing any other processing. If the measured resistance value goes out of the reference range, the TFC controller executes error handling processing in response to a resistance failure. As one of the error handling processing, the TFC controller notifies the host that the abnormality (resistance failure) has been detected in the resistance value of the TFC heater.

Abstract: Embodiments of the present invention allow for a precise altitude to be calculated from read-out signals of a head slider. In one embodiment, a hard disk controller/multiprocessing unit (HDC/MPU) determines a head element portion in which the instability has occurred in accordance with the resolution change. The HDC/MPU adjusts the clearance accordingly. The head element portion reads signals of different frequencies under a condition of the signal strengths coinciding with a reference value, and the HDC/MPU calculates the resolution. The HDC/MPU determines that the instability has occurred if the difference is outside the criterion. The HDC/MPU uses the read-out signal of a head slider in which the instability has not occurred to calculate the altitude.

Abstract: Embodiments of the present invention efficiently conduct a test for detecting defects on a magnetic disk more accurately. According to one embodiment, a HDD carries out defect inspection of a magnetic disk using thermal fly height control (TFC). Changing a clearance by the TFC achieves defect inspection tests under varied test conditions without much decrease of throughput in manufacturing HDDs. First, a self analysis test (SAT) is carried out in a state that a heater power of P2 is supplied to a heater. Then, another SAT is carried out in a state that a heater power of P1 is supplied to the heater. The heater power P2 is larger than the heater power P1.

Abstract: Embodiments in accordance with the present invention reduce the number of errors caused by the aged deterioration of a heater for adjusting the clearance between a head and a disk. According to one embodiment, a thermal fly height control (TFC) controller executes the measurement of a resistance value of a heater in a predetermined timing. The TFC controller judges whether or not the measured resistance value falls within a predetermined reference range. If the measured resistance value falls within the reference range, the processing ends without performing any other processing. If the measured resistance value goes out of the reference range, the TFC controller executes error handling processing in response to a resistance failure. As one of the error handling processing, the TFC controller notifies the host that the abnormality (resistance failure) has been detected in the resistance value of the TFC heater.

Abstract: Embodiments of the present invention allow for a precise altitude to be calculated from read-out signals of a head slider. In one embodiment, a hard disk controller/multiprocessing unit (HDC/MPU) determines a head element portion in which the instability has occurred in accordance with the resolution change. The HDC/MPU adjusts the clearance accordingly. The head element portion reads signals of different frequencies under a condition of the signal strengths coinciding with a reference value, and the HDC/MPU calculates the resolution. The HDC/MPU determines that the instability has occurred if the difference is outside the criterion. The HDC/MPU uses the read-out signal of a head slider in which the instability has not occurred to calculate the altitude.

Abstract: Embodiments of the present invention efficiently conduct a test for detecting defects on a magnetic disk more accurately. According to one embodiment, a HDD carries out defect inspection of a magnetic disk using thermal fly height control (TFC). Changing a clearance by the TFC achieves defect inspection tests under varied test conditions without much decrease of throughput in manufacturing HDDs. First, a self analysis test (SAT) is carried out in a state that a heater power of P2 is supplied to a heater. Then, another SAT is carried out in a state that a heater power of P1 is supplied to the heater. The heater power P2 is larger than the heater power P1.