Abstract: An apparatus and method for demagnetizing a write head of a disc drive. Under control of a clock oscillator, synthetic demagnetizing pulses are generated and applied to a writer-driver bridge. Also under control of the clock oscillator, a write current produced by the writer-driver bridge incorporates the demagnetizing pulses and ramps down to about zero. The train of demagnetizing pulses and the write current ramp down demagnetizes the head, reducing write head magnetic bias that may influence the proximate read head of the disc drive head.

Abstract: A reproducing head including a read element, first and second electrodes provided at the opposite ends of the read element, a ground electrode provided between the first and second electrodes, a first constant current circuit for passing a first constant current between the first electrode and the ground electrode, and a second constant current circuit for passing a second constant current between the second electrode and the ground electrode. The reproducing head further includes a computing unit connected to the first and second electrodes for synthesizing an output from the first electrode and an output from the second electrode, and a storing unit having a table showing the relation between a synthetic value computed by the computing unit and the outputs from the first and second electrodes.

Abstract: The present invention relates generally to the storage and/or retrieval of information on magnetic storage media by using one or more novel approaches alone or in combination. These novel approaches are capable of using at least one code which may comprise more than two values (i.e., more than a “0” and a “1”). A series of approaches applies generally to existing electric and/or magnetic storage/retrieval systems (e.g., magnetic, magneto-optic, etc.) as well as other novel electrical/magnetic systems. Each series of approaches is capable of storing information in one or more codes, wherein such approaches permit, if desired, the use of at least one higher order code which is different from the traditional binary code of “0's” and “1's” currently utilized for the storage of digital information.

Abstract: An information recording method in a rotating storage apparatus comprising a rotating recording medium for recording information, a head for performing at least a write operation onto the rotating recording medium, and an acceleration sensor for detecting a shock. The method comprises outputting a shock out signal if an output from the acceleration sensor exceeds a predetermined threshold. A signal is output at a first level for a write inhibit period in response to the input of the shock out signal, where the write inhibit period is selected based at least in part on a time span in which the output of the acceleration sensor exceeds the predetermined threshold. Writing to the rotating recording medium is prohibited during the write inhibit period.

Abstract: Systems and techniques relating to interpreting signals on a noisy channel with polarity uncertainty. A signal processor, such as a read channel transceiver device usable in a magnetic recording system, includes a detector operable to find a data pattern that indicates control information in a read signal and to determine a signal polarity of the read signal by determining Euclidean distances between a sampled sequence from the read signal and multiple possible sequences corresponding to preamble-shifted and polarity-reversed versions of the data pattern. The read signal is obtained from a partial response channel, such as in a storage device, and the data pattern can be a servo mark selected based on Euclidean distances between the servo mark and preamble-shifted and polarity-reversed versions of the servo mark generated according to a target channel and an encoding scheme specified for the storage medium.

Abstract: A magnetic recording media includes a servo region including a preamble region and a burst region and having marks of a magnetic film, and a data region having discrete tracks of the magnetic film. The burst region includes a signal section and a non-signal section, the signal section including rectangular marks of the magnetic film, in-plane geometry of which is a rectangle, formed in a periodic pattern in a track direction, and the non-signal section including marks of the magnetic film having a pattern different from the pattern of the rectangular marks in the signal section.

Abstract: An asymmetry compensator for measuring and correcting of asymmetry in magnetic recording devices. The magnetic recording device includes a read head, an asymmetry compensator, a data decoder, and an analog-to-digital converter. The read head produces a read data signal that contains potential errors due to asymmetry. The read data signal is processed into a compensated data signal by the asymmetry compensator. The asymmetry compensator includes a power of two squaring device, a gamma amplifier, and a summing junction connected in a feed forward manner. The gamma amplifier uses an approach involving, for a positive isolated pulse, the amplitude of the positive pulse and the undershoot and, for a negative isolated pulse, the amplitude of the negative pulse and the overshoot. The approach further involves probabilities and weights in a weighted average to account for any variations with frequency. The approach may be performed in either the analog or digital domain.

Abstract: An apparatus for use in applying write signals for driving a write head to effect writing information to a memory device; the write signals including a first write signal and a second write signal; includes: (a) a directing circuit receiving the write signals, directing a current to establish a voltage across the write head in a first excursion toward a first polarity in response to the first write signal and directing the current to establish the voltage across the write head in a second excursion toward a second polarity substantially opposite the first polarity in response to the second write signal; (b) a first boost system coupled with the directing circuit and boosting the write voltage toward the first polarity during the first excursion; and (c) a second boost system coupled with the directing circuit and boosting the write voltage toward the second polarity during the second excursion.

Abstract: A warning against the possible failure is accurately sent from the magnetic disk device to a host device. In one embodiment, error indices per unit time are stored discontinuously/continuously for each magnetic head, and if the new index (partial integral error rate) updated with the stored multiple error indices as the items to be monitored satisfies required conditions, this state is diagnosed as an abnormality or a pseudo-abnormality, and reported to the host device. The partial integral error rate is updated with an increase in the number of sets of error indices. Each time a new set of error indices per unit time are stored, the oldest of the existing error indices to be monitored is discarded and one of the new error indexes is added. In this way, a new partial integral error rate is calculated from the fixed number of new sets of error indices to be monitored.

Abstract: Selection of servo signals for peak detection of timing based servo tracks of magnetic tape for lateral positioning of heads relative to the magnetic tape. Servo signals from magneto-resistive servo read head(s) reading a magnetic tape are digitized by analog to digital converter(s); digital peak measurement apparatus is configured to sense the digital converter(s), and provide positive peak values and negative peak values of the digitized servo signals; and control apparatus is configured to determine the greater of the provided positive peak values or negative peak values, and select servo signals having the greater values for a servo channel. Servo apparatus is configured to respond to the selected servo signals to control the lateral positioning of the servo read head(s).

Abstract: A disk drive is disclosed comprising a disk having top and bottom surfaces, and top and bottom heads actuated over the top and bottom surfaces, respectively. Control circuitry detects a warping of the disk by writing a first test pattern to the top surface, reading the first test pattern to generate a first read signal, monitoring a first read signal value proportional to an amplitude of the first read signal, writing a second test pattern to the bottom surface, reading the second test pattern to generate a second read signal, monitoring a second read signal value proportional to an amplitude of the second read signal, and processing the first and second read signal values to detect a negative correlation between the amplitudes of the first and second read signals.

Abstract: A servo writer of the invention writes a servo signal in a magnetic tape, reads and inspects the signal, and has a servo writer main body and a plurality of unit panels changeably loaded to a panel change unit provided at the main body according to a product class of the tape, wherein any of the unit panels has a servo write head for writing the signal in the tape and a write-sub-control mechanism for controlling a writing of the signal by the write head, wherein the write head and the sub-control mechanism write a predetermined signal in the tape, and wherein the main body has a signal main control mechanism for mainly controlling a writing of the signal in the tape by the write head, a servo read head for reading the signal written in the tape, and a signal inspection mechanism for processing and inspecting the signal.

Abstract: Apparatuses and methods for detecting reference marks on magnetic data storage mediums are described herein. In one variation, the apparatus comprises a magnetic servo position demodulator operable to extract information from the magnetic data storage medium utilizing Partial Response/Maximum Likelihood (PRML) technique. Synchronization marks stored within the PRML channel is then detected utilizing a digital filter. For each of the detected synchronization mark, a further refined position of the synchronization mark can be determined utilizing a mathematical prediction model.

Abstract: A data track area and a servo pattern area are formed on a magnetic recording medium by embedding a nonmagnetic material inside concaves in a plurality of types of convex/concave patterns formed of a magnetic material on a substrate. The servo pattern area includes a plurality of types of first functional areas, in which control signals for disk access are recorded during manufacturing using the convex/concave patterns, and a second functional area, in which a convex/concave pattern of a different type to the convex/concave patterns of the respective first functional areas is formed and in which the nonmagnetic material is embedded so that an average height within the second functional area is substantially equal to an average height in the data track area.

Abstract: A flexible recording medium, which has a track width in the range of approximately 1-3 ?m, capable of facilitating good tracking control. A magnetic pattern bearing servo signals is provided on the guard bands formed on both sides of a data track of a magnetic recording medium. An improvement in tracking control is achieved by performing the servo tracking in a continuous manner.

Abstract: A disk drive includes a rotatable data storage disk, and head, a controller, and a preamplifier. The head is configured to write data to and read data from the disk. The controller is configured to generate a write current command. The preamplifier includes a plurality of write current parameters, and is configured to select among the plurality of write current parameters based on the write current command from the controller, and to generate a write current having a shape that varies based on which of the write current parameters are selected. The write current is provided to the head to write a plurality of data bits on the disk.

Abstract: An apparatus comprises a data storage medium having a plurality of servo sectors and a plurality of data sectors, wherein each of the servo sectors includes a phase locked loop field and a track identification field, a controller for controlling the position of a recording head with respect to the data storage medium, and a servo demodulator for recovering timing information from both the phase locked loop field and the track identification field, and for producing a timing estimate. The method performed by the apparatus is also included.

Abstract: The present invention relates to a magnetic recording media including servo zones having magnetic or nonmagnetic patterns which are utilized as servo signals including burst marks of a burst section adapted to detect off-track deviation, and data zones, in which the burst marks of the burst section in each of the servo zones are formed of an isolated nonmagnetic material surrounded by a magnetic material.

Abstract: A disk drive includes a rotatable data storage disk, a transducer, an actuator, and a controller. The transducer is configured to read and write data on the disk. The actuator is configured to position the transducer relative to defined portions of the disk. The controller is configured to determine how many times data has been written to the defined portions of the disk. The controller is also configured to refresh data residing at a particular one of the defined portions of the disk when the number of times data has been written to the particular defined portion of the disk satisfies a threshold value.

Abstract: Apparatus using information about the extent of errors in sensed data for performing as a control function at least one of adjusting the position of a magnetic head to improve alignment relative to a track and selecting from two or more data signals a data signal having the least amount of errors is shown. The apparatus uses information about the extent of errors to perform a control function for reproducing the data stored in predetermined storage locations in a storage media. The apparatus positions a transducer for sensing from predetermined storage locations stored data containing at least one constraint. The transducer generates a first signal representative of the data containing at least one constraint stored in the sensed data and any errors introduced into the sensed data during the sensing.