Abstract: The present disclosure is directed to systems and methods of compensating for thermal decay of a magnetic data storage medium. In a particular embodiment, the method includes reading a calibration track on a magnetic data storage medium to obtain a first measurement of a track characteristic. The method also includes overwriting the calibration track with a first specific data pattern and reading the calibration track to obtain a second measurement of the track characteristic. The method also includes determining whether a thermal decay rate of the calibration track is acceptable based on the first measurement and the second measurement.

Abstract: Data recovery, following a read error in a hard disk drive, is provided which includes an adjustment of fly height. In one embodiment, some re-reads are performed by both adjusting the fly height and the off-track positioning of the read head. In one embodiment, two or more fly heights are normally used during read/write operations such as in a zoned manner, and adjustments to fly heights are performed with respect to the fly height for the zone where the error occurred.

Abstract: A disk drive provides temperature compensation for write current. The write current not only provides an acceptable bit error rate for data written to and read from the disk, but also prevents write induced instability in the head. Furthermore, the write current prevents excessive pole tip protrusion. As a result, the write current ensures that data is reliably stored and retrieved at a given temperature.

Abstract: A method and apparatus to control the amount by which thermal expansion causes a write head to extend toward a disk is provided. In one aspect, a single write operation uses two or more different write currents. A first write current is initially used, and is large enough to achieve desired magnetic flux at the disk. After the write current heats and expands the arm tip, and extends it toward the disk surface, the write current is reduced, to avoid or postpone the time at which thermal expansion might cause the tip to contact the disk, or cause other undesirable effects.

Abstract: A method and apparatus for detecting a high flying condition of a transducer head in a computer disk drive is provided. The method and apparatus allow the detection of high fly write events that occur over one or a small number of data sectors. In addition, the present invention provides a method and apparatus for detecting high fly write events with a great deal of sensitivity. The method and apparatus of the present invention provide quick response and high sensitivity by monitoring the strength of a signal derived from data written to the disk, and signaling a high fly write event if the monitored signal strength in connection with a particular piece of data is less than a stored high fly write number corresponding to that piece of data by a predetermined amount.

Abstract: An adaptive error recovery routine allows for the recovery from errors in read data of a disk drive. In one embodiment, a disk drive is provided which has an error memory having error memory elements used to record an error type and recovery step for each error recovered from the disk drive. If another error is detected that is of the same type and which is in a location close to a recorded error, the error recovery step used for the previous error is performed for the new error. If the previous error recovery step is not successful, the disk drive performs error recovery using an existing error recovery table, and omits the previous error recovery step.

Abstract: Conventional border, drop shadow and/or matte outline generating signals are selectively gated through an offset amplifier of less than unity gain and then fed back into the existing delay lines, to selectively modify the horizontal and vertical trailing edge of the waveform generated by the loop, which, in turn, modifies accordingly the selectively switched composite video signal, i.e., provides for selectively increasing the size and/or varying the configuration of the luminance key signals.