Abstract: A disc drive includes a base and a disc rotatably attached to the base. The disc drive also includes an actuator assembly rotatably attached to the base and a device for moving the actuator assembly. The actuator assembly includes an arm carrying a write head in a transducing relationship with respect to the disc. The write head further includes a preamp current driver circuit. A data pulse circuit is operatively coupled to the preamp current driver circuit to provide a write current impulse based on an input data pattern. The preamp current driver circuit further includes a plurality transistors to receive the write current impulse and provide a sequence of write current impulses of opposite polarity to the write head for effecting magnetic recording on the disc of the disc drive based on the input data pattern.

Abstract: An adjustable impedance boosting circuit for a magneto-resistive head in a gain stage beyond the input gain stage. The boosting circuit compensates for a frequency pole of the head leads by introducing a zero in proportion to the resistance of the magneto-resistive element and with selectable circuit parameters to further adjust the pole compensation. The invention includes selectively adjusting the sensitivity of the pole compensation to changes in the resistance of the head, selectively adjusting the peak compensation, and adjusting the frequency of the compensating zero.

Abstract: An apparatus and method for detecting synchronous (SYNC) signals written on a disk memory device is performed by dividing a reproduced SYNC pattern, which includes a predetermined number of symbols, into a plurality of groups. Each of the plurality of groups includes at least one symbol that overlaps a symbol contained in another group. The invention outputs a SYNC detected signal when the symbols of at least one of the divided groups match the symbol of the SYNC pattern. In order to detect the SYNC signal, the invention increases the number of symbols included in each of the divided groups even when a large defect exists in the disk memory device.

Abstract: The invention discloses in one embodiment a parallel probe array (N×M) incorporating thermal near-field heaters (or writers) as well as magnetic sensors (or readers), which can be moved en bloc as well as independently of each other. To this end, the present invention uses a suitable controlling electronics for coordinating a parallel or quasi-parallel reading/writing, as well as controlling the positioning of an individual probe in an array. The control electronics enables the addressing of an individual or preselected set of probes, for controlling reading and/or writing, thereby securing the considerable advantage of versatility and efficiency of reading/writing in a parallel operation mode.

Abstract: In a coding method which does not restrict a run length of “1” while data is recorded/reproduced, there are such a drawback that when an error correction is carried out, a total number of error data to be corrected is increased, and also errors of not-detectable data are increased. While data is coded, a continuous number of “1” contained in a code word is limited, and then an error correction is carried out inside a coding/decoding process operation. Thus, a recording/reproducing apparatus having a small number of decoding errors is available.

Abstract: A magnetic head includes a multi-layer coil for generating a magnetic field, and a flat, magnetic field regulator spaced from the coil along the central axis of the coil. The field regulator is formed with a center hole for passing disk-illuminating light. The magnetic member consists of a plurality of sections that are electrically insulated and arranged around the central axis of the coil.

Abstract: A preamplifier circuit is disclosed comprising a data input for receiving write data, a read signal output for outputting an amplified read signal, a read signal input for receiving a read signal from a read element, and a write signal output for supplying a write signal to a write element. The preamplifier circuit further comprises a first amplifier circuit, responsive to the write data, for generating the write signal supplied to the write element, and a second amplifier circuit for amplifying the read signal from the read element to generate the amplified read signal output via the read signal output. A head control circuit, responsive to head select data, simultaneously enables the first and second amplifier circuits to perform a simultaneous read and write operation.

Abstract: A recording clock generating apparatus for a data recording system includes a wobble signal sampler which samples a wobble signal, from wobble grooves of an optical disk. A first phase comparator provides a first phase-difference signal based on a difference in phase between the wobble signal and a first recording clock signal. A prepit detector detects a prepit signal from prepits of the optical disk. A second phase comparator provides a second phase-difference signal based on a difference in phase between the prepit signal and the first recording clock signal. A phase control signal generator provides a phase control signal based on a sum of the first phase-difference signal and the second phase-difference signal. A clock generator provides a second recording clock signal having a phase corrected in response to the phase control signal provided by the phase control signal generator.

Abstract: Apparatus in a disc drive for transferring data between a rotatable disc and a host computer. An analog pre-processor integrated circuit device incorporates circuitry to carry out analog processing functions including write current driving, readback signal amplification, prewrite compensation, frequency-domain filtering, and equalization. A digital post-processor integrated circuit device incorporates circuitry to carry out digital signal processing functions including Viterbi detection, decoding, error detection and correction, buffering, host interface functions, and data encoding and serialization. The analog pre-processor is preferably mounted within the interior environment of the disc drive to an actuator assembly that supports a head adjacent the disc. The digital post-processor is preferably supported on a printed circuit board mounted to an exterior surface of the disc drive.

Abstract: A write amplifier circuit in a magnetic storage system has a cross coupling circuit and an active damp circuit to supply an improved write current to the head writing the data onto the media within the magnetic storage system. The inclusion of the cross coupling circuit decreases a rise time and a fall time associated with the write current. The active damp circuit reduces the undershoot and ringing of the write current. Thus, the write amplifier circuit is suitable for high speed data storage writing applications requiring minimal distortion of the data written to a magnetic medium. The write amplifier circuit achieves these improvements in the waveform of the write current by incorporating circuit elements and using both a negative feedback path and a feedforward path.

Abstract: A transducing head for perpendicularly writing data to a magnetic medium having a recording layer and a soft magnetic underlayer comprises a perpendicular write transducer for writing data into the recording layer and a DC magnetic writer having legs in spaced relation to generate a magnetic field along tracks of the magnetic medium. The magnetic field writes a DC magnetic effect longitudinally into the soft magnetic underlayer, thereby reducing noise due to the operation of the perpendicular write transducer.