Abstract: Embodiments of the invention provide a disk drive capable of writing information on data tracks even more positively when a shingle write method is adopted. In one embodiment, the disk drive is characterized in that, when information is to be written on a plurality of adjacent data tracks on a recording medium through the shingle write method, writing of information is controlled by detecting an actual writing position based on servo information recorded on the recording medium and determining whether or not the detected actual writing position meets a predetermined condition.

Abstract: Embodiments of the invention provide a disk drive capable of writing information on data tracks even more positively when a shingle write method is adopted. In one embodiment, the disk drive is characterized in that, when information is to be written on a plurality of adjacent data tracks on a recording medium through the shingle write method, writing of information is controlled by detecting an actual writing position based on servo information recorded on the recording medium and determining whether or not the detected actual writing position meets a predetermined condition.

Abstract: In a magnetic recording drive having a plurality of magnetic heads each employing a magnetoresistive sensor for the purpose of averaging the time required for sense currents to be caused to flow through the respective magnetoresistive sensors to shorten the longest reproducing time and to suppress the degradation of the characteristics due to the electromigration, thereby improving the reliability of the magnetic recording drive, the magnetic recording drive includes circuits for averaging the useful life depending on the currents caused to flow through the respective magnetoresistive sensors among the plurality of magnetic heads, whereby the time required for the sense current to be caused to flow through one MR reproducing head is greatly shortened. Therefore, the levels of outputs of the MR reproducing heads can be increased without reduction of the reliability and thus the reliability of the magnetic recording drive can be improved.

Abstract: In a magnetic recording drive having a plurality of magnetic heads each employing a magnetoresistive sensor for the purpose of averaging the time required for sense currents to be caused to flow through the respective magnetoresistive sensors to shorten the longest reproducing time and to suppress the degradation of the characteristics due to the electromigration, thereby improving the reliability of the magnetic recording drive, the magnetic recording drive includes circuits for averaging the useful life depending on the currents caused to flow through the respective magnetoresistive sensors among the plurality of magnetic heads, whereby the time required for the sense current to be caused to flow through one MR reproducing head is greatly shortened. Therefore, the levels of outputs of the MR reproducing heads can be increased without reduction of the reliability and thus the reliability of the magnetic recording drive can be improved.

Abstract: A magneto-optical data recording system comprises magnetic field pulse applying means for applying to a magneto-optic recording medium a magnetic field pulse of a polarity corresponding to code data to be recorded, and means for heating the recording medium in a pulsating manner at a predetermined frequency synchronous with the code data to be recorded. During recording, the magnetic field pulse applying means applies a magnetic field pulse of a polarity corresponding to code data along a track of the recording medium and the heating means continuously heats the recording medium in a pulsating manner at a predetermined frequency synchronous with the code data to thereby directly overwrite the code data. The magnetic field pulse applying means includes a magnetic coil driven by code data from a source of code data (data generator).

Abstract: A magnetic disk apparatus includes a dual head equipped with an MR head for reading data and an inductive head for writing the data. One ID portion and one servo pattern are disposed in one sector and an unequal track pitch is formed. The ID portion is formed at the center of a radius of two positions to which the MR head is positioned at the time of reading the data and writing the data, respectively.

Abstract: A magneto-optical data recording system comprises magnetic field pulse applying means for applying to a magneto-optic recording medium a magnetic field pulse of a polarity corresponding to code data to be recorded, and means for heating the recording medium in a pulsating manner at a predetermined frequency synchronous with the code data to be recorded. During recording, the magnetic field pulse applying means applies a magnetic field pulse of a polarity corresponding to code data along a track of the recording medium and the heating means continuously heats the recording medium in a pulsating manner at a predetermined frequency synchronous with the code data to thereby directly overwrite the code data. The magnetic field pulse applying means includes a magnetic coil driven by code data from a source of code data (data generator).

Abstract: A magneto-optical data recording system comprises magnetic field pulse applying means for applying to a magneto-optic recording medium a magnetic field pulse of a polarity corresponding to code data to be recorded, and means for heating the recording medium in a pulsating manner at a predetermined frequency synchronous with the code data to be recorded. During recording, the magnetic field pulse applying means applies a magnetic field pulse of a polarity corresponding to code data along a track of the recording medium and the heating means continuously heats the recording medium in a pulsating manner at a predetermined frequency synchronous with the code data to thereby directly overwrite the code data. The magnetic field pulse applying means includes a magnetic coil driven by code data from a source of code data (data generator).

Abstract: A sensing current adjusting zone is formed in the outermost or innermost periphery of a magnetic disk and reference signals are recorded in a recording width corresponding to the width of a plurality of tracks in the sensing current adjusting zone so that the phases of the reference signals are the same and the radially adjacent reference signals overlap each other. When adjusting the sensing current, an MR head is moved forcibly into the sensing current adjusting zone to reproduce the reference signal and the sensing current is adjusted so that the difference between the respective absolute values of the plus peak and the minus peak of the reproduced reference signal is reduced to the least extent.

Abstract: In a magnetic disk apparatus of high-speed data transfer, in order to cover an uncompensable section of the thermal asperity by error code correction to shorten the uncompensable section, upper and lower envelopes of a reproduced waveform are detected to obtain a level variation waveform due to the thermal asperity and subtract it from the reproduced signal. A thermal asperity processing circuit shown in FIG. 1 for compensating for the thermal asperity is used. In an envelope detection circuit in the thermal asperity processing circuit, a forced charge and discharge current control circuit is used in the thermal asperity portion to thereby be able to improve the follow-up characteristic to level variation of the thermal asperity and shorten the uncompensable section.

Abstract: Increased memory capacity for a magnetic disk device is realized without degrading information error rate, by making the number of sectors at a given circumference of the disk variable in accordance with a radial direction of a disk. The number of sectors is made variable by deciding a predetermined information error rate from a ratio of reproduced signal output to noises of head, disk and amplifier at a maximum recording and reproducing frequency at a certain radial position along a disk.

Abstract: A magneto-optical data recording system comprises magnetic field pulse applying apparatus for applying to a magneto-optic recording medium a magnetic field pulse of a polarity corresponding to code data to be recorded, and apparatus for heating the recording medium in a pulsating manner at a predetermined frequency synchronous with the code data to be recorded. During recording, the magnetic field pulse applying apparatus applies a magnetic field pulse of a polarity corresponding to code data along a track of the recording medium and the heating apparatus continuously heats the recording medium in a pulsating manner at a predetermined frequency synchronous with the code data to thereby directly overwrite the code data. The magnetic field pulse applying apparatus includes a magnetic coil driven by code data from a source of code data (data generator).

Abstract: In a magnetic recording drive having a plurality of magnetic heads each employing a magnetoresistive sensor for the purpose of averaging the time required for sense currents to be caused to flow through the respective magnetoresistive sensors to shorten the longest reproducing time and to suppress the degradation of the characteristics due to the electromigration, thereby improving the reliability of the magnetic recording drive, the magnetic recording drive includes circuits for averaging the useful life depending on the currents caused to flow through the respective magnetoresistive sensors among the plurality of magnetic heads, whereby the time required for the sense current to be caused to flow through one MR reproducing head is greatly shortened. Therefore, the levels of outputs of the MR reproducing heads can be increased without reduction of the reliability and thus the reliability of the magnetic recording drive can be improved.

Abstract: A magneto-optical data recording system comprises magnetic field pulse applying apparatus for applying to a magneto-optic recording medium a magnetic field pulse of a polarity corresponding to code data to be recorded, and apparatus for heating the recording medium in a pulsating manner at a predetermined frequency synchronous with the code data to be recorded. During recording, the magnetic field pulse applying apparatus applies a magnetic field pulse of a polarity corresponding to code data along a track of the recording medium and the heating apparatus continuously heats the recording medium in a pulsating manner at a predetermined frequency synchronous with the code data to thereby directly overwrite the code data. The magnetic field pulse applying apparatus includes a magnetic coil driven by code data from a source of code data (data generator).

Abstract: Increased memory capacity for a magnetic disk device is realized without degrading information error rate, by making the number of sectors at a given circumference of the disk variable in accordance with a radial direction of a disk. The number of sectors is made variable by deciding a predetermined information error rate from a ratio of reproduced signal output to noises of head, disk and amplifier at a maximum recording and reproducing frequency at a certain radial position along a disk.

Abstract: A magnetic recording and reproducing apparatus, comprising a magnetic recording medium, a head arrangement for reading data from or writing data on the magnetic recording medium including an inductive recording head and a magnetoresistive reproducing head, and a phase discriminating circuit for discriminating data `1` from peaks of a waveform reproduced by the head. The phase discriminating circuit has a differential circuit for differentiating the waveform, a pulse circuit for producing a zero cross pulse from a zero-level crossing point of the differentiated waveform, a discriminating circuit for discriminating `1` and `0` of the data with use of pulses output from the pulse circuit and a discriminating window needed for judgment of `1` and `0` of the data, and a decoding circuit for decoding and feeding out the data output of the discriminating circuit. The head comprises a recording head of inductive type, and a reproducing head of magnetoresistive type.

Abstract: A waveform equalizer for processing a signal read by a magnetic head from a magnetic written medium includes a slimming circuit which, in turn, has a first delay unit for delaying the read signal, a first attenuator connected in parallel with the first delay unit, a first differentiating circuit for receiving the output from the first delay unit and the output from the first attenuator, and a resistor connected to a first delay unit side input of the first differential circuit; and a pseudo-peak elimination circuit connected in series with the slimming circuit and including a circuit for separating the from the read signal the read signal or a signal reverse in phase to the read signal, a second delay unit for delaying the separated signal, a second attenuator for attenuating the amplitude of the separated signal, and a second differential circuit for receiving the read signal and the separated, delayed and attenuated signal.

Abstract: A recording medium is provided with a recording film having opto-magnetic characteristics formed on the substrate, with first information being recorded in advance in the form of pit strings of a phase structure. Second information is recorded over the first information through the application of a magnetic field with polarities corresponding to the second information in the presence of the irradiation of a high-power radiation beam, without damaging the record of the first information. The first and second information are produced independently and simultaneously with a single spot in the same area by use of different signal reproduction mechanisms for the first information and second information.

Abstract: A constant-density type of magnetic disk apparatus is made up of a plurality of magnetic disks, wherein at least one of the surfaces of the magnetic disks is a servo face divided into a plurality of zones in the radial direction of the disks. A magnetic disk used in this apparatus and a servo-writing device for making this magnetic disk are also disclosed. In the magnetic disk apparatus and the magnetic disk, servo information regions and clock information regions are alternately provided on the servo face in the circumferential direction of the disks. The servo information regions are arranged radially with respect to the rotation center of the disks and each of the clock information regions includes a plurality of magnetic transitions representative of clocks, the number of which is different for each of the divided zones.

Abstract: A magneto-optical data recording system includes magnetic field pulse applying apparatus for applying to a magneto-optic recording medium a magnetic field pulse of a polarity corresponding to code data to be recorded, and a heating apparatus for heating the recording medium in a pulsating manner at a predetermined frequency synchronous with the code data to be recorded. During recording, the magnetic field pulse applying apparatus applies a magnetic field pulse of a polarity corresponding to code data along a track of the recording medium and the heating apparatus continuously heats the recording medium in a pulsating manner at a predetermined frequency synchronous with the code data to thereby directly overwrite the code data. The magnetic field pulse applying apparatus includes a magnetic coil driven by code data from a source of code data (data generator).