Abstract: A peak detection circuit receives a playback signal from a magnetic storage medium and generates a peak detection signal. A shift register transmits the peak detection signal, and a pattern detection circuit is responsive to signals from the shift register to detect a first predetermined temporal pattern of peaks in the peak detection signal. A pattern correction circuit adjusts the relative timing of peaks in the peak detection signal so that the first predetermined temporal pattern of peaks in the peak detection signal is converted to a second predetermined temporal pattern of peaks in a corrected peak detection signal.

Abstract: A method sets bit densities and track densities for a plurality of heads in a data storage device. The method includes determining an initial bit density and an initial track density for each head. An initial total capacity for the storage device is determined based on the initial track densities and the initial bit densities. A desired capacity for the storage device is selected and the initial total capacity and the desired capacity are compared. One of either a bit density or a track density is then adjusted so that the data storage device has an adjusted capacity that provides some excess capacity over the desired capacity where the excess capacity is less than any excess capacity that was present between the initial capacity and the desired capacity. A data storage device formed through this method is also provided.

Abstract: A method and apparatus for removing second order distortion is disclosed. The method couples a differential load between two source followers of a gain stage. The apparatus includes a differential load having two MOS transistors of unequal channel width/length ratios. The differential load implements a square and summing function in a single circuit eliminating the need to split the signal path.

Abstract: An information storage device (10, 510, 610, 710) includes a cradle (12, 512, 612, 712) which can removably receive a cartridge (11, 411, 511, 611, 711). The cartridge contains a rotatably supported disk (91, 326-327), and a pivotal actuator arm (101) which supports a read/write head (107, 331-334) for movement adjacent the disk. A coil (117) on the arm interacts with an external magnetic field to effect pivotal movement of the arm. The cartridge may contain a spin motor (92) for effecting rotation of a disk. A preamplifier (111) and an electrostatic discharge buffer (112) are provided for the head. A read-only memory (186) contains characteristic information about the cartridge, and an hour meter (191) contains information about the cumulative amount of time that the cartridge has been used. A connector (71) is provided to electrically couple external circuitry to electrical components within the cartridge.

Abstract: This invention provides a read/write channel with a multiplex input/output system for a disk drive, which may have one or more magnetic disks, one or more read/write heads, and a read/write channel. The read/write channel may comprise a multiplex input/output (I/O) terminal, a write output driver, and a digital to analog converter. The read/write channel may be implemented on an integrated circuit. The multiplex input/output system may send different signals or voltages through the same input/output terminal at essentially at the same time or different periods of time.

Abstract: An apparatus and method for removing baseline shift in low frequency readback signals of a disc drive, such signals characterized by peaks separated by baseline portions. The disc drive comprises a head controllably positionable adjacent tracks on a rotatable disc, a servo circuit which controls the position of the head in response to the readback signals and an adjustable filter operably connected to and serially disposed between the head and the servo circuit. When baseline shift is detected in the baseline portions of the readback signals at a predetermined margin threshold, the response characteristics of the adjustable filter are adjusted to remove the detected baseline shift from the readback signals.

Abstract: Apparatus for detecting defects in a magnetic disk includes a read head including multiple read elements for reading multiple tracks of the disk. Read signals produced by the read elements are received by certifier circuit portions for determining whether any of the read signals includes an indication of a defect in the disk. A monitoring circuit monitors the read elements to detect a malfunctioning read element. The read head position is controlled so that a malfunctioning read element is not used.

Abstract: A method and apparatus for detecting and respond to low-amplitude-write/skip-write events in a disc drive. The invention involves characterizing the gain factor of a variable gain amplifier embedded in the read path of a disc drive during at least two instances in which the read head passes over a servo sector, prior to a write event. Next the write event is executed. After the write event, the gain factor employed by the variable gain amplifier is acquired as the read head passes over the following servo sector. Finally, the acquired gain factor is compared to the characterization in order to detect a low-amplitude-write/skip-write event.

Abstract: A data storage system includes a data storage disc for storing magnetically encoded data and servo information. The data storage disc includes a data layer adapted to be magnetically encoded with data to be written to the data storage disc, and a servo information layer formed beneath the data layer and having magnetic servo pits formed therein to provide servo information. The magnetic servo pits are positioned in portions of the servo information layer which are at least partially directly beneath magnetically encoded data regions on the data layer such that a data head can read both magnetically stored data and servo information from the disc at substantially the same time. A method of fabricating a magnetic data disc is also disclosed.

Abstract: A master-information magnetic recording apparatus for recording preformat information signals into a magnetic recording medium using a ferromagnetic film pattern formed on a master information carrier, in which the pattern corresponds to the preformat information signals. With the master information carrier in contact with the magnetic recording medium, the ferromagnetic film pattern is magnetized by a magnetic field applying device. Thus, the preformat information signals are recorded into the magnetic recording medium. The magnetic field applying device is so constructed that the direction of magnetizing the ferromagnetic film pattern is perpendicular to a track-scanning orbit of a magnetic head in a recording and reproducing apparatus in which the magnetic recording medium is installed. It enables the magnetic head to gain sufficient reproduction amplitude for track-scanning for reproducing the information signals.

Abstract: A method for allocating tracks into servo sector zones in a disk drive such that each zone has an equal range of channel bit densities is provided. In addition, a disk drive having servo sector zones that each have an equal range of channel bit densities is provided. According to the method and apparatus of the present invention, servo sector zones are sized such that the range of servo sector channel bit densities encompassed by each zone is constant from zone to zone. By constraining the range of channel bit densities encompassed by the servo sector zones, the equalization or conditioning of signals derived from the servo sectors can be optimized for a given number of zones. Accordingly, the method and apparatus of the present invention increases the accuracy with which servo sector data is detected while decreasing the complexity of the detector circuit.

Abstract: A method and apparatus for providing adaptive drive-level compensation for amplitude and BER loss due to media thermal decay is disclosed. Specifically, in one embodiment, a disk surface having information stored thereon is provided. The information is written in the form of magnetic transitions, which are subject to thermal decay. A head is used to read the information stored on the disk surface and is biased by a bias current (or a bias voltage). A value related to the thermal decay of the magnetic transitions is determined. If the value indicates that the thermal decay has reached an unacceptable level, the bias current is increased in order to compensate for the thermal decay of the magnetic transitions. Once a bias current limit has been reached, information stored on the disk surface is rewritten.

Abstract: A mobile device is disclosed comprising a disk storage system including a disk and a head actuated over the disk, wherein the disk comprises a data area. The mobile device further comprises a motion detector for detecting a relative velocity and distance of a foreign object with respect to the mobile device. When the motion detector detects an impending impact with the foreign object, retracting circuitry within the mobile device retracts the head away from the data area of the disk.

Abstract: Embodiments of a data storage tape control system and methods are disclosed that may work to correct off-track errors, reduce the frequency of off-track errors, and/or reduce the negative effects of off-track errors in writing performance. The invented method slows tape speed in response to off-track errors, preferably by continuously decelerating while attempting writing multiple retries. The invented method helps prevent further off-track errors and the resulting frequent interruptions of writing, by helping improve head placement accuracy. Once a selected amount of data is written, for example, a standard data-set or other block of data, the tape speed optionally may be accelerated to the original target speed. While the average tape speed may be reduced during the invented writing procedure, the overall efficiency of writing may be increased compared to an operation in which off-track errors and writing failures occur repeatedly because of high tape speeds.

Abstract: Synchronous acquisition in a sampled amplitude read channel. A timing error estimation unit (302) is provided to calculate an acquisition timing error. The estimate is based on use of synchronous (interpolated) samples and an approximation to an arctangent function.

Abstract: An improved sampled amplitude read/write channel is provided. The system is an integrated Generalized Partial Response Maximum Likelihood (GPRML) read channel incorporating Read, Write, and Servo modes of operation. One implementation includes a 32/34 rate parity code and matched Viterbi detector, a 32 state Viterbi detector optimal parity processor, robust frame synchronization, self-adaptive equalization, thermal asperity detection and compensation, adaptive magneto-resistive asymmetry compensation, low latency interpolated timing recovery and programmable write precompensation.

Abstract: The overvoltage applied on a head during switching of the head is prevented. At the time when the head switching signal changes, a switch S4 for turning on/off an operational amplifier Gm1 is turned off, and the operational amplifier Gm1 is turned off. Simultaneously, the switch S3 is turned on, the current source I1 is connected to a capacitor C1, and the capacitor C1 is discharged. Then, switches S1 and S2 for switching the MR head are switched. Finally, the switch S3 is turned off and the switch S4 is turned on, thus the switching of the MR head is finished.

Abstract: A magnetic recording apparatus equipped with a recording circuit for generating a recording current corresponding to an input recording signal, a magnetic head, operable in response to the generated recording current, for recording, in a magnetic recording medium, data corresponding to the input recording signal, and a waveform shaping section for shaping the generated recording current such that a current value of said recording current approximates to a predetermined value while keeping thereover throughout a period corresponding to the data length. Both the recording circuit and the waveform shaping section may be mounted in an integrated form on a single microchip. The result is that the input recording signal can be transferred at high speed as measures are provided to reduce both a rise time and a fall time of the recording current.

Abstract: A data eraser applies a strong magnetic field to a magnetic disk while suppressing the strength of a magnetic field applied to a spindle motor. The data eraser includes an upper magnet fixer, a lower magnet fixer, and a linkage. The upper magnet fixer fixes one set of permanent magnets and the lower magnet fixer fixes another set of permanent magnets. The plate members are provided at the tips of the upper and lower magnet fixers. The plate members are made of a soft magnetic material, for example, JIS SS400, respectively. Each of these plate members functions as a yoke.

Abstract: Sampling data with wide bi-phase code symbols includes sampling a wide bi-phase code symbol in the data a number (N) of times to produce samples of data, selecting a subset of the samples, determining which sample in the subset of samples has a largest magnitude, and selecting a subset of samples in a subsequent wide bi-phase code symbol based on a sample in a previous subset that has the largest magnitude.