Abstract: Embodiments in accordance with the present invention reduce the structural stress applied to a head, and to achieve the effective control, when the clearance between the head and a disk is adjusted by using a heater. According to one embodiment, the hard disk controller/microprocessing unit (HDC/MPU) controls a slew rate of a heater at the time of TFC (Thermal Fly height Control). In response to processing conditions, a HDC/MPU changes a slew rate of the output of electric current/voltage applied to the heater. This makes it possible to reduce the head stress, and to achieve the effective TFC. To be more specific, with reference to a temperature/slew rate table, the HDC/MPU changes a slew rate in response to the temperature in the read/write processing.

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 in accordance with the present invention relate to improving error recovery process performance. A head slider in an embodiment of this invention includes a heater for adjusting a clearance between a head element section and a magnetic disk. During an error recovery process (ERP) for a reading error, if a particular environmental temperature is in a low-temperature region, a microprocessing unit (MPU) executes the ERP steps of increasing a heater power value of the heater (i.e., STEP X to STEP X+2), preferentially over the ERP steps of reducing the heater power (i.e., STEP X+3 to STEP X+5). In the low-temperature region, the possibility of error recovery in an earlier step can be raised by executing the heater power increasing ERP steps earlier than the heater power reducing ERP steps.

Abstract: Embodiments of the invention make it possible to conduct stable recording on a magnetic disk, even in case of changes in flying height due to thermal protrusion. In one embodiment, a compensatory recording current value A2 is used when a first section of user data is recorded in the required number of data sectors from the data sector of the starting address for recording the user data to the data sector of an intermediate address. A recording current value A3 smaller than the compensatory recording current value is used when a second section of user data is recorded in the data sectors existing from the data sector of the intermediate address towards the ending address.

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: A system and method for preventing crosstalk noise from being superimposed on a read signal due to noise from a heater line for a slider in a recording disk drive is disclosed. A heater line pair to the slider is not grounded but is in a floating state with respect to an actuator support structure. A heater driver allows a heater current to flow between a positive power supply voltage and a negative power supply voltage. The heater line pair is not grounded, so an impedance is high as viewed from a magnetic disk. Thus, it is possible to effectively suppress a noise transmitted from the magnetic disk and read signal quality is kept from deteriorating due to the crosstalk from the heater line.

Abstract: Embodiments of the present invention provide a process that monitors a magnetic playback signal while gradually increasing an electricity supply amount for a heater to thereby determine contact between a magnetic head slider and a magnetic disk medium. According to one embodiment, after components for configuring a magnetic recording/playback portion are assembled into a housing, magnetic information is played back on a specific track of a magnetic disk medium by using a playback element while gradually increasing an electricity supply amount for a heater of a magnetic head slider. An amplitude of a playback signal is measured at a plurality of portions along a circumferential direction of the track. Contact between the magnetic head slider and the magnetic disk medium is detected in accordance with an increase in variation in the measured amplitude.

Abstract: Embodiments of the invention reduce a possibility that a head will collide with a medium when the clearance between the head and the medium is adjusted by using a medium, and sufficiently reduce the clearance even at an initial stage of accessing a data area. In one embodiment, a hard disk drive (HDD) keeps a heater in an OFF state for a period of time from the start of seek operation until the specified timing after a following mode starts. This prevents a head element from colliding with a magnetic disk, and also prevents flying properties from changing due to the deformation of the ABS. In the above specified timing, the heater is switched from OFF to ON. Specifically, for example, on completion of seek operation, in the timing in which a head arrives at a target track, or in the timing in which an HDC/MPU enters the following mode, the heater is turned ON.

Abstract: Embodiments of the invention reduce a possibility that a head will collide with a medium when the clearance between the head and the medium is adjusted by using a medium, and sufficiently reduce the clearance even at an initial stage of accessing a data area. In one embodiment, a hard disk drive (HDD) switches a heater from OFF to ON in the specified timing after a seek mode is switched to a following mode. Specifically, for example, on the completion of seek operation, in the timing in which a head arrives at a target track, or in the timing in which an HDC/MPU enters the following mode, the heater is turned ON, and this state is kept unchanged until access to the target sector is made.

Abstract: Embodiments in accordance with the present invention reduce the structural stress applied to a head, and to achieve the effective control, when the clearance between the head and a disk is adjusted by using a heater. According to one embodiment, the hard disk controller/microprocessing unit (HDC/MPU) controls a slew rate of a heater at the time of TFC (Thermal Fly height Control). In response to processing conditions, a HDC/MPU changes a slew rate of the output of electric current/voltage applied to the heater. This makes it possible to reduce the head stress, and to achieve the effective TFC. To be more specific, with reference to a temperature/slew rate table, the HDC/MPU changes a slew rate in response to the temperature in the read/write processing.

Abstract: A system and method for preventing crosstalk noise from being superimposed on a read signal due to noise from a heater line for a slider in a recording disk drive is disclosed. A heater line pair to the slider is not grounded but is in a floating state with respect to an actuator support structure. A heater driver allows a heater current to flow between a positive power supply voltage and a negative power supply voltage. The heater line pair is not grounded, so an impedance is high as viewed from a magnetic disk. Thus, it is possible to effectively suppress a noise transmitted from the magnetic disk and read signal quality is kept from deteriorating due to the crosstalk from the heater line.

Abstract: Embodiments in accordance with the present invention relate to improving error recovery process performance. A head slider in an embodiment of this invention includes a heater for adjusting a clearance between a head element section and a magnetic disk. During an error recovery process (ERP) for a reading error, if a particular environmental temperature is in a low-temperature region, a microprocessing unit (MPU) executes the ERP steps of increasing a heater power value of the heater (i.e., STEP X to STEP X+2), preferentially over the ERP steps of reducing the heater power (i.e., STEP X+3 to STEP X+5). In the low-temperature region, the possibility of error recovery in an earlier step can be raised by executing the heater power increasing ERP steps earlier than the heater power reducing ERP steps.

Abstract: Embodiments of the invention reduce a possibility that a head will collide with a medium when the clearance between the head and the medium is adjusted by using a medium, and sufficiently reduce the clearance even at an initial stage of accessing a data area. In one embodiment, a hard disk drive (HDD) keeps a heater in an OFF state for a period of time from the start of seek operation until the specified timing after a following mode starts. This prevents a head element from colliding with a magnetic disk, and also prevents flying properties from changing due to the deformation of the ABS. In the above specified timing, the heater is switched from OFF to ON. Specifically, for example, on completion of seek operation, in the timing in which a head arrives at a target track, or in the timing in which an HDC/MPU enters the following mode, the heater is turned ON.

Abstract: Embodiments of the invention reduce a possibility that a head will collide with a medium when the clearance between the head and the medium is adjusted by using a medium, and sufficiently reduce the clearance even at an initial stage of accessing a data area. In one embodiment, a hard disk drive (HDD) switches a heater from OFF to ON in the specified timing after a seek mode is switched to a following mode. Specifically, for example, on the completion of seek operation, in the timing in which a head arrives at a target track, or in the timing in which an HDC/MPU enters the following mode, the heater is turned ON, and this state is kept unchanged until access to the target sector is made.

Abstract: Embodiments of the invention make it possible to conduct stable recording on a magnetic disk, even in case of changes in flying height due to thermal protrusion. In one embodiment, a compensatory recording current value A2 is used when a first section of user data is recorded in the required number of data sectors from the data sector of the starting address for recording the user data to the data sector of an intermediate address. A recording current value A3 smaller than the compensatory recording current value is used when a second section of user data is recorded in the data sectors existing from the data sector of the intermediate address towards the ending address.

Abstract: The present invention relates to controlling the flying height of a magnetic head or slider relative to a magnetic disk in a disk storage device. The flying height of the negative pressure slider is not affected by changes in temperature. By controlling a ratio of crown sensitivity of the flying height to camber sensitivity of the flying height, changes in flying height due to the crown change of the slider corresponding to temperature changes are canceled. It is necessary to set a ratio of the area of a reverse step surface, R, to the area of a center rail, C, within a range of 2:1 to 6:1 (preferably 4:1 to 6:1; ideally 5:1). Then, setting can be performed so that the center of the substantially negative pressure generated may be the center of the slider surface.