Abstract: An information storing device and an information processing device having a memory for registering a plurality of working modes at recording/reproduction and a switching circuit for selecting one of the plurality of working modes, which select the optimum working mode automatically or by an instruction of an operator according to power supply capacity of a device of higher rank to effect recording/reproduction.

Abstract: An apparatus for providing a read signal at an output locus for access by an information processing device receives an input signal containing the information; the apparatus includes: (a) a read signal control unit receiving the input signal at a control unit input locus; the control unit is coupled with the output locus and controls the read signal; (b) a plurality of switches; and (c) a plurality of bias arrays coupled with the switches. A first bias array set cooperates with the plurality of switches in a first orientation to couple the first bias array set with the control unit to establish a first operational mode. A second bias array set cooperates with the plurality of switches in a second orientation to couple the second bias array set with the control unit to establish a second operational mode.

Abstract: A system and method for acquisition signal error estimation is provided which uses one or more past values of the sequence to determine the nearest ideal sample value without comparing the received sample value to the potential sample values. According to one embodiment, the nearest ideal sample value is selected based on the received sample value and values of three consecutive samples. According to another embodiment, the nearest ideal sample value is selected based on the received sample value and a value of an immediately preceding sample. According yet to another embodiment, the nearest ideal sample value is selected based on the received sample value and a value of a previous sample. The acquisition signal error estimator maybe used in conjunction with gain, DC offset, or magneto-resistive asymmetry control loops in a sampled amplitude read channel.

Abstract: A method and apparatus for providing quadrature biasing for coupled-pair circuits. A QBCP-circuit for quadrature amplifiers provides a new input common-mode sense point that separates the inputs for the differential-and-common mode feedback-control loops. The QBCP circuit biases all four transistors equivalently and reduces the feedback-loop interaction, thereby simplifying the bias control system and improves the voltage-transfer frequency-response performance.

Abstract: A method and apparatus for providing matched differential MR biasing and pre-amplification. Tightly matched and well centered low-level MR bias voltage is provided directly to the sensing element for controlled input-impedance differential pre-amplification without common-mode voltage level control with loops.

Abstract: A head protection device in a data recording circuit is disclosed in which write-current of a given level that corresponds to a high or low level of coercive force of the magnetic recording portion of a recording medium is provided as an output and supplied to a magnetic head for data recording and reproduction. The data recording circuit comprises an alternate write-current supply portion for alternately providing, by a suitable current switching means, a low write-current corresponding to a low coercivity magnetic head and a high write-current corresponding to a high coercivity magnetic head, a common output portion for providing data to be recorded using a low current or a high current from the alternate write-current supply portion. The low coercivity magnetic head and the high coercivity magnetic head can be at least electrically switched. A current protection portion for a current switching means is provided so as to prevent generation of high write-current at the alternate write-current supply portion.

Abstract: A method and apparatus are provided for implementing improved phase alignment in a direct access storage device (DASD). A reference clock input is received for providing a system clock. Locking to a synchronization field of a readback signal is performed by adjusting the phase of the system clock. A timing mark is detected and then the adjusted phase of the system clock is held. Responsive to the detected timing mark, a reference delay of a predefined number and fraction of system clock periods is identified. At an end of the reference delay, a write circuit accepts data and generates write signals for a write operation. The phase of the system clock is adjusted corresponding to a predefined fractional delay and is used to run a programmable counter that counts the predefined number of system clock periods corresponding to the reference delay.

Abstract: A programmable write equalization circuit includes a first digital clock that is used as a reference to indicate data rate, a second digital clock used to indicate write equalization quantization, a look-up table used to store waveforms used in equalizing the input from the first digital clock domain to the second digital clock domain, a counter used to indicate the number of bits within the look-up table that are to be used for each translation, a polarity detector used to detect the current state of the input data, a non-return-to-zero (NRZ) filter used to indicate the placement of data transitions and non-transitions, and a software interface including programmable registers to control each one of the parameters within the equalization circuit.

Abstract: A system and method enable boosting a bias applied to a load so as to facilitate reversing the direction of the bias applied relative to the load. The amount of boosting provided to facilitate reversing the bias polarity, depends on a substantially fixed boost voltage, which can be programmable. Thus, by setting the boost voltage to a predetermined voltage improved performance can be achieved, including, for example, improving the rise and/or fall times of bias current applied to an inductive load.

Abstract: A storage device stores a plurality of information, each having first and second partial information. A reading device reads the first partial information of one arbitrarily selected information to be reproduced, and the corresponding first partial information is reproduced. Also, a reading device reads the second partial information of the arbitrarily selected information during the reproduction of the first partial information.

Abstract: An apparatus and method of indirectly measuring half frequency whirl in a spindle motor having a rotor adapted to rotate a disc having a track which is followed by a transducer head that is actuated by a control system is provided. Vibration signals produced at the transducer head while the transducer head follows the track are detected. The half frequency whirl is determined as a function of the detected vibration signals.

Abstract: A measuring apparatus and a method is provided for measuring performance characteristics of a recording unit including a circular recording medium on which one track is divided into a plurality of sectors, where the recording unit records a data signal on the recording medium by using a magnetic head. A mechanism device including micro actuator and a piezo-electric stage moves the magnetic head in a direction substantially perpendicular to a circumferential direction of the recording medium in response to a control signal. The measuring apparatus writes a write signal for respective sectors while moving the magnetic head by outputting the control signal having different levels corresponding to respective sectors to the mechanism device, and reads out the written write signal, then measuring a read-out write signal as a read signal relative to a position of the magnetic head.

Abstract: A magnetoresistive element measurement circuit configured for measuring resistance of a magnetoresistive element biased by a current source is disclosed. In a preferred embodiment, the measurement circuit includes the magnetoresistive element, a current source providing a fixed current to the magnetoresistive element, at least one current bypass switch controllingly engaging a measurement resistor in an electrical parallel configuration with the biased magnetoresistive element, and an analogue voltage detector measuring voltage first across the biased magnetoresistive element and then across the biased magnetoresistive element in electrical parallel communication with the measurement resistor. The measured voltages are factored with the measurement resistor to determine the resistance of the magnetoresistive element.

Abstract: A method for determining presence or absence of a low flying read/write head is disclosed. In a preferred embodiment, a disc is accelerated to an operating rotational velocity, a voltage is applied across a magnetoresistive element of the read/write head, the voltage applied across the magnetoresistive element is monitored for an occurrence of a contact event voltage signature, a level of the voltage applied across the magnetoresistive element concurrent with the occurrence of the contact event voltage signature is determined and compared to a predetermined applied voltage threshold to determine presence of a low flying read/write head. Occurrence of a contact event voltage signature prior to reaching the predetermined applied voltage threshold identifies the read/write head as a low flying read/write head. Non-occurrence of a contact event voltage signature prior to reaching the predetermined applied voltage threshold identifies the read/write head is a non low flying read/write head.

Abstract: Bi-Variant Coupled Pair (BVCP) circuits suitable for use in channel front-end low noise preamplifiers of magnetic storage devices are described. In a magnetic storage device, a BVCP circuit provides a DC bias voltage for a read transducer, low-noise amplification performance, and relatively small AC coupling capacitor values for reducing the cost of an integrated circuit (IC) in which the BVCP circuit may be embodied. The BVCP circuit also has a controllable input impedance for matching a transmission line impedance for high data rate applications.

Abstract: The invention provides a method for performing magnetic transfer by bringing a master carrier for magnetic transfer and a slave medium in close contact with each other and by applying a magnetic field for transfer, whereby a product (Ms1&dgr;1) of saturation magnetization (Ms1) and film thickness (&dgr;1) of a magnetic layer of the master carrier to be used for magnetic transfer on a surface of the slave medium with earlier magnetic transfer and a product (Ms2&dgr;2) of saturation magnetization (Ms2) and film thickness (&dgr;2) of a magnetic layer of the master carrier are in a relation of: 1.5<(MS2&dgr;2)/(Ms1&dgr;1)<10, and a transfer magnetic field (Hdu1) applied to the surface with the earlier magnetic transfer and a transfer magnetic field (Hdu2) on the surface of the slave medium with the subsequent magnetic transfer are in a relation of: 0.2≦Hdu2/Hdu1≦0.9.

Abstract: A rotary magnetic head apparatus which can be formed into a smaller size in which signals of a plurality of recording tracks which are recorded on a tape-like information recording medium are reproduced by using a plurality of reproduction heads without depending on the arrangement of the recording tracks in the information recording medium. The rotary magnetic head apparatus includes a rotary drum, a fixed drum, a reproduction signal selection device, a rotor reproduction signal wiring section, and a stator reproduction signal wiring section.

Abstract: Techniques for detecting control data, such as servo data, from input or incoming data read from a magnetic recording medium in the presence of radial incoherence are provided. More specifically, the techniques employ multiple (i.e., two or more) data detectors for choosing between multiple sampling phases associated with the input data read from the magnetic recording medium. In the context of servo data detection, such techniques offer several orders of magnitude in performance improvement in detecting SAM and Gray data in the presence of RI and may advantageously be employed in a read channel integrated circuit. Furthermore, such techniques may be applied to any data encoding system.

Abstract: Digital data recording apparatus includes a modulator for modulating a recording clock by a recording data. A reference voltage and a reference current in signal processing are set based on a reference clock having a multiple cycle of the cycle of the recording clock when the reference clock is supplied via a rotary transformer. A demodulator demodulates a modulation signal supplied via the rotary transformer to produce a demodulation signal, from which a recording signal is generated for recording on a recording medium. The demodulator obtains a modulation signal and an inverted modulation signal from which first and second saw-tooth wave signals are produced when the reference current is supplied. A mixer mixes the first and second saw-tooth wave signals, and the demodulation signal is obtained, based on the mixer output and the reference voltage.

Abstract: For scanning a disc-shaped information carrier at a high average information rate with minimum access time, the angular velocity is decreased substantially as the radial distance to the scan location increases, while at the same time the linear velocity of track scanning increases substantially. The track may be divided into zones which are scanned with constant angular velocity. With respect to the inner tracks of at least two adjacent zones, or the innermost and the outermost tracks, the angular velocity decreases less than inversely with increase of radial distance, while the linear velocity increases less than proportionally with increase of radial distance.