Abstract: A data write control method of a hard disk di ive which can prevent the loss of data by sensing an abnormal flying height of a transducer head luring a data write operation. In the method, servo information is read from a write medium to compare an amplitude level of the servo information with a prescribed setting value. If the amplitude level of the servo information is less than the setting value, a flying height of a transducer head from the write medium is determined not suitable for the data write operation. A write disable flag is set to change the disk drive to a write non-ready state until the flying height of the transducer head is suitable for the data write operation.

Abstract: The present invention is a method and apparatus for removing transient DC level shifts caused by thermal asperities. A read signal is generated by a transducer in response to proximate contact between the transducer and magnetic flux fields recorded on a magnetic media surface. The read signal is provided to a continuous time filter and a sampler. During normal operation, the output of the sampler is provided directly to a fixed delay tree search detector. Upon encountering a thermal asperity, the output of the sampler is first provided to a 1-D sampled filter which removes the DC shift caused by the thermal asperity and then to the fixed delay tree search detector, which provides signal recovery. A multiplexer provides selection of the output signal from between sampler and the 1-D sample filter.

Abstract: A magnetic recording system utilizing a plurality of surfaces on a magnetic recording disk with recording zone boundaries established on the respective surfaces of the disk based on performance characteristics of the read/write transducer associated with the surface. The performance of the read/write transducer from the aspects of the width of the track written by the transducers as well as the recording performance at the expected recording frequency, are both utilized in building disk drives. Since the zone boundaries are established uniquely for the performance of each transducer, rather than by defining the boundaries of all zones for all surface in advance based on assumed performance characteristics of the heads, the zone boundaries on one surface of the disk will not necessarily align with the zone boundaries on another surface of the disk. Similarly, when a plurality of disks are utilized, the zone boundaries will not necessarily be aligned.

Abstract: A digital audio signal processing apparatus for creating coded edited data by insertion of second coded audio data coded in block units not synchronized with frames and fields into first coded audio data coded in block units also not synchronized with the frames and the fields at a request made by a command signal synchronized with the frames or the fields comprises coding means for creating the first and second coded audio data, and switching means for receiving the first and second coded audio data whereby selective switching of the first coded audio data and the second coded audio data from one to another is carried out at a location selected among a position specified by the command signal and positions before or after the specified position when the selected location coincides with a boundary between two consecutive coded blocks of the first and second coded audio data.

Abstract: A digital magnetic reproducing apparatus comprises a reproducing head to reproduce data from a magnetic recording medium; an equalizer for shaping, by a partial response method, the waveform of the reproduced signal outputted from the reproducing head; and a decoder for decoding, by a maximum likelihood decoding method, the equalized reproduced signal obtained from the equalizer. The reproducing head employed in this apparatus is an MR (magnetoresistance effect) head which is capable of reducing the second harmonic distortion of the reproduced signal to be -25 dB or lower. Therefore the deterioration of the bit error rate that may result from the nonlinear distortion of the MR head can be further lowered within a sufficiently suppressed range in practical use.

Abstract: A magnetic recording/reproduction apparatus of an azimuth system for recording/reproducing a digital signal by helical scanning a magnetic tape has an SP mode and an LP mode having recording/reproducing time period N (N is an even number) times that of SP mode. The apparatus includes a pair of magnetic head units with opposite azimuth, disposed in close proximity on a circumferential face of a rotary head cylinder with difference in level therebetween corresponding to a predetermined track pitch t for scanning simultaneously two continuous tracks at that pitch. The cylinder is rotated at the same rotation speed in both SP and LP modes, while the tape travel speed is reduced to 1/N that of SP mode when LP mode is specified. When LP mode is specified, the data amount of a digital signal to be recorded is compressed to 1/N that in SP mode, which are provided to the magnetic heads 2-channel record data, and the data amount of reproduced 2-channel digital signals of is expanded by N.

Abstract: A head-switching circuit for switching a first head operating on a first recording medium to a second head operating on a second recording medium so as to read out data written on a recording medium according to a staggered servo mechanism, includes a selector for selecting one of the recording media, a classifier 20, 30, 31, 32 and 33 for classifying the skew time of a recording medium selected by the selector and another recording medium selected by the selector, a sync signal generator 40, 41, 42, 50, 51, 60, 61, 62, 70, 71, 72 and 80 enabled by the output signal of the classifier and for generating a sync signal when the skew time is identical with a predetermined time, thereby generating a sync signal precisely during head-switching in staggered servo mechanism.

Abstract: A storage device is described which has a plurality of different error recovery routines which are are divided into groups. When an error occurs, specific routines are selected from the groups in accordance with the error type. The selected routines are executed in order. By preferentially executing the selected routines corresponding to the error type, the error recovery rate in the early stages of the error recovery procedure is enhanced.

Abstract: An apparatus for correcting read errors in a disk drive is disclosed. In one embodiment, the apparatus includes circuitry for determining that an undesired distortion exists in a data signal read from a surface of a data storage disk; circuitry for finding an approximate starting location of said distortion within said data signal; and, circuitry for correcting errors in said data signal caused by said undesired distortion using said approximate starting location of said distortion. A method for correcting read errors in a disk drive is also disclosed.

Abstract: There is provided a magnetic tape drive capable of attaining a stable read-out output value of information even if a tracking displacement occurs. The magnetic tape drive of the present invention is a magnetic tape drive for 36-track comprising a magnetic tape 1a having a width of 1/2 inch and having information written therein by an 18-track magnetic tape drive, a plurality of magnetic heads 2, 3 for performing a reading of information of each of the tracks in the magnetic tape 1a and a control section 9 for controlling a writing or reading operation for information from the magnetic heads 2, 3, wherein as the magnetic heads, each of the forward reading head 2 and the reverse reading head 3 is installed in correspondence with each of the tracks of the magnetic tape 1a.

Abstract: In an information recording/reproducing apparatus, frame synchronization is speedily performed when initialization is executed or the recording surfaces are switched, and the reliability of recorded data is improved. Segment IDs, each being formed by coding an information word representing a rotational angle measured from a rotational angle origin, are provided within the respective servo areas in such a manner that they are spaced equally in the track direction. While initial synchronization is performed, frame synchronization is established based on the information obtained by decoding the segment ID. This eliminates the need for detecting a home index pattern, thereby speedily performing the initial synchronizing operation. After initial synchronization is achieved, it is constantly monitored whether a frame is not out of synchronization based on the information obtained by decoding the segment ID.

Abstract: In the recorded magnetization state measurement method of this invention, a recorded magnetization pattern formed on a medium is first detected by a magnetic force microscope (MFM). An MFM output signal extractor then extracts a one-dimensional MFM output signal along the direction of recording at a prescribed MFM reproduction width from the recorded magnetization pattern detected by the magnetic force microscope. A waveform value analyzer then calculates as output reproduction the average value of amplitude of the MFM output signal extracted by the MFM output signal extractor and calculates as medium noise the standard deviation of amplitude of the MFM output signal.

Abstract: A technique for method for positioning a magneto resistive head located upon an actuator arm onto a loading ramp of a storage unit. The technique includes the steps of operating a removable magnetic disk at a first number of revolutions per second, the magnetic disk having an outer diameter, positioning the magneto resistive head adjacent to the removable magnetic disk, reading data from the removable magnetic disk, detecting a reset signal, producing a back electro-motive force in response to the reset signal, biasing the magneto resistive head towards the outer diameter of the removable magnetic disk in response to the reset signal and to the back electro-motive force, reducing a number of revolutions per second for the removable magnetic disk from the first number to a second number of revolutions per second, the first number greater than the second number; thereafter using an energy storage unit to bias the magneto resistive head onto the loading ramp, in response to the reset signal.

Abstract: A read/write head for a magnetic medium magnetic is modified by the addition to it of a parallel-connected resistor and by the measurement of the difference in voltage at the terminals of this unit, on the one hand when the read/write head and the resistor are perfectly connected and, on the other hand, when one of the connections is in an open circuit condition or even in short-circuit condition with respect to ground. Consequently, a measurement is taken, preferably, of the state of connection of the read/write head when it is in read mode and not when it is in write mode. It is shown that far greater reliability in the detection of this type of defect is obtained, in avoiding false alarms.

Abstract: A disc reproduction device, in which at the time of normal reproduction, a rotational speed of a spindle is detected based on a reproduction signal from the disc by a rotational speed counting circuit, a control signal that makes a speed error with respect to a reference speed zero is given to a first VCO as the control voltage thereof, a reproduction clock is generated while controlling the frequency and phase at a digital PLL circuit by using the oscillation output thereof as the reference frequency of the first PLL circuit containing a second VCO and in which, at the time of access, the control signal to the first VCO is switched to the output signal of the phase comparator by the switch circuit under the control of the controller and a multiple PLL circuit containing the first VCO, phase comparator, LPF, and so forth, is constituted to make the oscillation frequency of the first VCO track the reproduction speed at the destination of access predicted based on the access information by the controller.

Abstract: An apparatus for recording a digital information signal and a subcode signal in slant tracks (FIG. 1) on a record carrier (140), includes an input (111) for receiving the digital information signal and an input (123) for receiving the subcode signal. Portions of information of the subcode signal are accommodated into subcode signal blocks (FIG. 2) and portions of information of the information signal are accommodated into information signal blocks (main sync blocks, FIG. 1). The subcode signal blocks and the information signal blocks are combined into a composite signal for recording the tracks on the record carrier. Time code signals are generated and accommodated in specific subcode signal blocks in the subcode signal recording portion having sequence numbers that satisfy the following formula:N(i)={N(i-1)+1+2.multidot.p}mod2.sup.m,where p is an integer positive constant for which holds 0.ltoreq.p.ltoreq.2.sup.

Abstract: A semiconductor integrated circuit device including pairs of lower level input/output terminals 6 and 7 and pairs of high capacity input/output terminals 8 and 9, high capacity read amplifiers 10 and 11 and high capacity write drivers 14 and 15 both of which are connected to the pairs of high capacity input/output terminals 6 and 7, lower level read amplifiers 12 and 13 and the lower level write drivers 16 and 17 both of which are connected to the pairs of lower level input/output terminals 8 and 9, in which outputs from the high capacity read amplifiers 10 and 11 and outputs from the lower level read amplifiers 12 and 13 are outputted to data output terminals 36 and 37 via an amplifying circuit 35 and an output from a data input terminal 40 is outputted selectively to either one of the high capacity write drivers 14 and 15 and the lower level write drivers 16 and 17 by a write data forming circuit 39.

Abstract: A staggered servo writing technique of a hard disk drive includes the steps of: setting a plurality of cylinders on disks to a group, writing servo information on each cylinder of the group set above by a specified head, and writing servo information on the remaining cylinders of the disks.

Abstract: A system and a method are provided for making magnetic recording servo tracks with inherent dropout robustness and with encoded track set information, longitudinal position information and other information recorded during tape or disk manufacture. A tape is provided having at least two servo tracks of opposite polarity recordings separated by a transition region. Servo data signals are produced for recording on the at least two tracks of the tape during a single pass during manufacture of the tape. The servo data signals are derived from MR elements that determine the polarity of the servo data signals.

Abstract: A method and apparatus are described for controlling a phase of the data window, using data patterns in addition to any dedicated sync patterns to improve the synchronization when decoding data from a magnetic recording medium, such as, for example, a floppy diskette. A data window is generated to separate the data pulses from the clock pulses in a pulse series which has been recorded using a method which generates peak shifts such as MFM (Multi-Frequency Modulation) or FM. When a pulse series that matches any of a set of predetermined bit patterns is found in the data, the phase of the data window signal is adjusted based on the deviation of the timing of a selected transition in the pattern from the expected ideal value. Preferably the bit patterns have a plurality of symmetrically arranged bits and include a criterion position that is not affected by a peak shift. The pulse series from the recording medium is separated into data pulses and clock pulses by using the adjusted data window.