Abstract: A tape head assembly comprises a transducer head having plural arrays of transducing elements, the transducing elements comprising at least one of write elements and read elements. The tape head assembly further comprises a set of conditioning elements, the conditioning elements comprising at least one of write drivers and read amplifiers. Multiplexing circuitry selectively couples the conditioning elements to one of the plural arrays of transducing elements.

Abstract: The invention enables a magnetic disk drive to be inserted and removed against an attraction force exerted by a magnetic force that is strong enough to erase data on a magnetic disk enclosed within a metal case. A converting mechanism comprising a ballscrew and a ballscrew nut bracket is provided that converts rotational motion of a handle into translational motion of an HDD holder; by rotating the handle, the HDD holder with the hard disk drive mounted thereon is moved in the inserting and removing directions by overcoming the attraction force being exerted by the magnetic field generated by means of a permanent magnet. An electric motor may be used to generate the rotational force.

Abstract: A method and system are disclosed for providing a variable speed digital read channel. The read channel includes an analog portion and a digital portion. The read channel includes an analog-to-digital converter (ADC) for converting an analog read signal into a sampled read signal. The ADC is synchronized to a sample clock. The sample clock has a variable clock rate. The digital portion includes a digital filter for reducing noise. The digital filter can be implemented as a low pass filter (LPF), a high pass filter (HPF), or a bandpass filter (BPF). The filter receives the sampled read signal from the ADC. The digital filter is synchronized to the sample clock. The digital filter's cutoff frequencies adjust automatically as the variable clock rate is changed, and does not require reprogramming. The digital portion may also include a digital automatic gain control device.

Abstract: A driver circuit drives a write element for magnetic recording, and permits high speed recording while preventing noise from entering an adjacent read element. An H bridge circuit, which causes a write current to flow, in accordance with a write drive signal, in a write coil of the write element, is provided with an overshoot circuit, in which positive and negative power sources are of the same potential. It makes a flyback voltage vertically symmetrical. Further, a feedback circuit is provided which monitors the voltages at both ends of the write coil, and prevents a variation in the common potential of the write coil. Terminal resistors are further provided to prevent the effects of reflection in a transmission line, and to prevent a change in the write waveform.

Abstract: In recovering data originally written on a carrier of magnetic media after a catastrophic failure, data may be read without prior knowledge of the write channel by which the data was originally written and in the presence of intersymbol interference of the readback signal. This is accomplished by forming an image of the spatial response function of the magnetoresistive transducer used to recover the data and by forming an image of the raw data read from the carrier of magnetic media by the magnetoresistive transducer for which the response function has been characterized. An image of the distribution of virtual magnetic charge on the carrier of magnetic media is obtained through deconvolution of the image of the response function of the magnetoresistive transducer and the raw readback signal. The readback signal corresponding to the data originally written on the carrier of magnetic media is then recovered by spatial differentiation of the image of virtual magnetic charge.

Abstract: A disk drive of a perpendicular magnetic recording type uses a double-layered disk. The disk has a plurality of tracks for storing data and a non-recording region (GB area) between tracks. Not a DC magnetized pattern but an AC magnetized pattern or a random magnetized pattern is recorded in the GB area. With this structure, it is possible to prevent an influence of magnetic disturbance due to a DC magnetic field on the surface of the disk.

Abstract: A method of optimizing design parameters of a data storage system in which a failure of products is caused by changes in the time required for using the products and characteristics of the products is pre-estimated. Design parameters used in a signal processing circuit in the pre-estimated failure condition are optimized and stored. A signal is processed using the design parameters optimized in the pre-estimated failure condition if errors occur due to changes in conditions of use of the data storage system. According to the method, the period and frequency of use of the data storage system can considerably be extended.

Abstract: A method of forming a magnetic transition pattern in a longitudinal magnetic recording medium, comprising steps of: (a) providing a magnetic recording medium including a layer of a magnetic material having a surface comprised of a plurality of longitudinally extending magnetic domains; (b) contacting the surface of the layer of magnetic material with a topographically patterned imprinting surface of a stamper/imprinter formed of at least one high saturation magnetization, high permeability magnetic material; and (c) applying a unidirectional magnetic field perpendicular to the imprinting surface of the stamper/imprinter, the perpendicular magnetic field creating a longitudinal magnetic field component of sufficient strength to effect selective alignment of the magnetic domains of those portions of the layer of magnetic material which face the depressions of the imprinting surface while retaining the alignment of the magnetic domains of those portions of the layer of magnetic material which face the project

Abstract: A system and method provide overshoot protection to facilitate driving a load by output circuitry in response to a transition from a first operating mode to a second operating mode. The overshoot protection occurs by masking an input bias from biasing the output circuitry for an initial part of the second operating mode based on a transition to the second operating mode, and then allowing the input bias to bias the output circuitry in a desired manner in a subsequent part of the second operating mode.

Abstract: A disk drive is disclosed which has a facility to perform a pinning reset operation on a GMR read element included in a head if a read retry operation fails to achieve recovery from a read error. When a bias and write currents are supplied to the head, a CPU of the disk drive determines an optimum bias and write currents on the basis of a temperature measured value of the GMR read element.

Abstract: A voltage regulator includes an output node and first and second regulator circuits. The first regulator circuit generates a first regulated voltage on the output node when a supply voltage equals or exceeds a predetermined threshold, and the second regulator circuit generates a second regulated voltage on the output node when the supply voltage is less than the predetermined threshold.

Abstract: A self-vaccine as used herein will refer to methods of operating a disk drive and the apparatus implementing such methods, which make the disk drive immune to changes in temperature, that keep the disk drive healthy when hot or cold. The invention includes a self-vaccine extending the read channel optimization parameter database of a track zone or sequence to test temperature ranges actually found in the user's operation of the disk drive. The invention also includes the self-vaccine updating the read channel optimization parameter database for an already tested temperature range, whenever there has been sufficient time passed since the read channel optimization was performed for that temperature range. The invention includes read channel optimized parameters for at least temperature ranges within the embedded disk controller, which are updated in the user's operating environment during idle time providing the self-vaccine. The invention includes disk drives including a self-vaccine method.

Abstract: The invention provides a method insuring that each read channel optimization step is controllable in terms of quality divergence, that a systematic response can be made which can be readily automated. The method is applicable to a pre-existing read channel optimization (RCO) script. The method includes the following operations. Acquiring a first quality measure and a first parameter list. Performing the pre-existing RCO script creating a second quality measure and a second parameter list based upon the first parameter list. Convergence processing the first and second quality measures and parameter lists.

Abstract: A bias circuit for a magneto-resistive head having a bias current output circuit for flowing a bias current through a magneto-resistive head, and a feedback circuit for controlling the bias current from a bias current output circuit by detecting voltage variation across the magneto-resistive head so that a voltage across the magneto-resistive head becomes a predetermined value. The bias current output circuit comprises a regulating circuit for regulating an operation of the bias current output circuit in the bias current output circuit, a control circuit for controlling the regulating circuit to be in a predetermined condition, and a switching circuit for switching a read/write condition for activating the control circuit for the regulating circuit in a non-read condition of the magneto-resistive head. The regulating circuit includes an oscillation suppressing capacitor; and the control circuit for the regulating circuit is a charging circuit for the oscillation suppressing capacitor.

Abstract: In order to solve a problem that it takes a long time to shift from a write mode to a read mode when there is a cross talk of an output signal of a recording head to a reproducing amplifier side, there is provided a reproducing amplifier including an amplifier circuit portion having a differential pair of transistors is provided with a switching circuit comprised of switches connected with resistors, which supply a bias voltage to each base of the differential pair of transistors, respectively in parallel. The switching circuit turns on for a write mode period and for a fixed period after a change from the write mode to a read mode to decrease the input impedance of the reproducing amplifier for the periods.

Abstract: A magnetic disk device having a magnetic disk for recording information, a rotary mechanism for rotating the magnetic disk, a magnetic head unit for recording information on the rotating magnetic disk, a slider having mounted thereon the magnetic head unit and flying over the rotating magnetic disk, a magnetic head supporting mechanism for supporting the slider, and a positioning mechanism for setting the magnetic head unit at a predetermined radial position. The magnetic head supporting mechanism has mounted thereon an integrated circuit (IC) for amplifying an information write/read signal of the magnetic head unit, and a control circuit is connected to the IC. A recording frequency is controlled according to the radial position of the IC on the magnetic disk by the control circuit.

Abstract: One circuit generates a constant positive potential, another circuit generates a constant negative potential. The positive potential and the negative potential are applied to a magneto-resistive head that reads data from and writes data to a magnetic disk. The positive potential is generated using a positive voltage source, an operational amplifier, and an NMOS transistor. The negative potential is generated using a negative voltage source, an operational amplifier, and a PMOS transistor.

Abstract: A method of erasing a disk by applying a direct current to a transducer while the transducer is moved in a selected manner relative to the rotating disk. The rotating disk in conjunction with the erasing transducer moving in a first direction in a substantially continuous and smooth manner yields a helical shaped erased path on the disk. Such helical erasure of the disk is faster than conventional erasure method that erases the disk by erasing in concentric circular paths. To erase in circular paths, the transducer needs to be positioned on that circular path, and positioning of the transducer involves a repositioning time that can be significant. The helical erasure method substantially eliminates the repositioning time since the path of the transducer is substantially continuous and smooth. The reduction in erasure time by use of helical erasure method is substantial when compared to the total erasure time.

Abstract: A method to erase a magnetic tape, where the magnetic tape is first mounted in a magnetic tape in a tape drive, where that magnetic tape includes a physical beginning of tape (“PBOT”), a physical end of tape (“PEOT”), and information written thereon between the PBOT and the PEOT. The method then establishes one or more critical areas located on the magnetic tape, attempts to erase the information, and determines if each of the one or more critical areas have been erased. In the event each of said one or more critical areas have not been erased, Applicants' method provides an error message.

Abstract: A method of tuning a bias parameter for a magnetoresistive head in a data storage system includes the step of identifying, from multiple possible bias parameter values, a smallest bias parameter value for the magnetoresistive head which both maintains a bit error rate above a predetermined threshold bit error rate, and which satisfies a second criteria. The method then includes the step of setting an operational bias parameter value for the magnetoresistive head to the identified smallest bias parameter value. Also disclosed are data storage systems, or controllers which are connectable to or included with data storage systems, configured to implement the methods.

Abstract: A magnetic circuit is provided in an enclosure that can efficiently generate magnetic flux from the enclosure, configuring a magnetic disk, to a magnetic disk. Thus, by providing such a magnetic circuit, a magnetic field different from that in other enclosure parts, that is, a local magnetic field, is generated from the magnetic circuit in case the disk device is set in an external magnetic field. Hence, this local magnetic field can effectively erase data in the magnetic disk. In particular, since the local magnetic field is generated even if the external magnetic field is weak, it is possible to not only suppress the demagnetization of permanent magnets used in the spindle motor at minimum, but also effectively erase data in the magnetic disk.

Abstract: The invention includes operating a merged read/write head in a disk drive by determining both the maximum read bias current and maximum write current, based upon the measured read resistance of the read mechanism and the write current in use with the write mechanism. Both the read mechanism and write mechanism are near each other in the merged read/write head.

Abstract: A disk drive of perpendicular magnetic recording method including a read head comprising a GMR element and a drive using a double-layered disk medium, is disclosed. In the magnetic field response characteristic of the GMR element, the relationship between the degree of nonlinearity and a pulse width at 50% threshold (PW50) of a differentiated read signal is used. The degree of nonlinearity of the GMR element is adjusted such that the PW50 is smaller than the maximum value. The read channel comprises a differentiation circuit for converting the read signal output from the GMR element into the differentiated read signal.

Abstract: A magnetic head driving circuit includes a main driving circuit symmetrical with respect to a centered recording coil, and at least two pairs of adding circuits, each pair including a positive pulse adding circuit and a negative pulse superposed circuit symmetrical with respect to the centered coil. And, by reversing the direction of the magnetic head coil current, at least one of the adding circuits is made to operate and make it as a magnetic head driving circuit for adding a potential equal to or higher than the power supply, thereby to drive as a sub-driving circuit arranged symmetrically with respect to the centered coil, which promotes the reversal of the magnetic head coil current, and which drives stably with a central potential of the coil at about the disk potential.

Abstract: A circuit controls the gain of an amplifier that amplifies an information signal. The circuit includes a buffer for storing first and second samples of the amplified information signal, and a gain-determination circuit coupled to the buffer. The gain-determination circuit generates a gain adjustment based on the sum of the first and second samples, the gain adjustment causing the amplifier to change the amplitude of the amplified information signal to or toward a predetermined amplitude. Such a circuit can provide an initial, coarse gain adjustment to a read-signal amplifier in a disk-drive read channel. Compared to prior read channels, this initial adjustment promotes faster settling of the amplifier gain at the beginning of a data sector. This faster settling allows the data sector to have a shorter preamble, and thus allows the disk to have a higher data-storage density.

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 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: Arm electronics (AE) suitable for use in a disk drive are disclosed. The AE has write circuitry configured to operate the AE in a write mode during which a write mode supply current is drawn, and read circuitry configured to operate the AE in a read mode during which a read mode supply current is drawn. The AE uses a decaying current pulse generator that generates a decaying current pulse at the beginning of each write-to-read mode transition. The decaying current pulse has an initial value that is equal to the difference between the write mode supply current and the read mode supply current. This controlled load forces the AE to draw a gradually decreasing supply current for each write-to-read mode transition such that supply voltage transients (otherwise present due to parasitics in cabling between the AE and power supply) are reduced. Thus, the undesirable effects of such transients in the read circuitry are reduced so that write-to-read mode recovery times can be shortened.

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 of tuning a bias parameter for a magnetoresistive head in a data storage system includes the step of identifying, from multiple possible bias parameter values, a smallest bias parameter value for the magnetoresistive head which both maintains a bit error rate above a predetermined threshold bit error rate, and which satisfies a second criteria. The method then includes the step of setting an operational bias parameter value for the magnetoresistive head to the identified smallest bias parameter value. Also disclosed are data storage systems, or controllers which are connectable to or included with data storage systems, configured to implement the methods.

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 system, method and computer program product provide an annealing process for setting a magnetization condition of a read head. An amount of heat for stabilizing magnetization condition of a read head is calculated. A width and amplitude of a voltage pulse that generates the calculated amount of heat in the read head are calculated. A voltage pulse of the calculated width and amplitude is applied to the read head for generating Joule heating in the read head. The width of the voltage pulse is less than one second.

Abstract: This invention provides a magnetic recording/reproducing apparatus with high storage capability and an areal recording density over 7.75 Gbits/cm2, in which fluctuation of readback output and decay of magnetization or erasure of recorded magnetization in the recording layer are prevented. On the substrate of a magnetic disk, a soft magnetic underlayer and a perpendicular recording layer are formed in order, where the soft magnetic underlayer has a triple-layered structure in which a domain control layer including an anti-ferromagnetic layer is sandwiched between two first and second soft magnetic layers. Given that thickness of the first soft magnetic layer is d1 and thickness of the second soft magnetic layer is d2, d1 and d2 should be between 25 nm and 150 nm and a ratio of d1/d2 should fall within a range of 0.3 to 1.5. Thereby, magnetic domains in the soft magnetic underlayer of a perpendicular magnetic recording medium are controlled and magnetic domain wall motion can be inhibited.

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: An improved bias circuit for a disk drive head which reduces or eliminates transients while switching biasing. Embodiments of the invention are directed to eliminating transients while switching the bias of a MR head such as from current bias to voltage biasing. In an embodiment of the present invention, bias enable signals from a control circuit are inputs to delay circuits. The delay circuits provide a delay on the high-to-low transition, and essentially no delay on the low-to-high transition. The unsymmetrical delay ensures that the read head bias current will continue to be driven during the biasing transition to reduce voltage swings that could damage the head.

Abstract: A disk drive is disclosed which has a facility to perform a pinning reset operation on a GMR read element included in a head if a read retry operation fails to achieve recovery from a read error. When a bias and write currents are supplied to the head, a CPU of the disk drive determines an optimum bias and write currents on the basis of a temperature measured value of the GMR read element.

Abstract: A magnetic recording process includes applying an initial magnetic field to magnetize a magnetic recording medium and positioning a ferromagnetic mask over the magnetic recording medium. The ferromagnetic mask has a tooth which shields a portion of the magnetic recording medium in order to maintain the initial magnetic field in the portion. The process also includes applying a biasing magnetic field to the magnetic recording medium and applying a recording magnetic field to the magnetic recording medium while applying the biasing magnetic field. The biasing magnetic field is substantially perpendicular to the initial magnetic field and the recording magnetic field is substantially opposite in polarity to the initial magnetic field.

Abstract: Apparatus responsive to a signal derived by a magnetic transducer includes a variable gain amplifier arrangement having an input responsive to the signal and an output terminal. An analog gain control circuit responds to the signal at the output terminal. An analog to digital converter responds to the signal at the output terminal. Circuitry responsive to an output signal of the analog gain control circuit and an output signal of the analog to digital converter causes the gain of the variable gain amplifier to be simultaneously controlled in response to gain control output signals resulting from the output signals of the analog gain control circuit and the analog to digital converter. Both gain control output signals are derived in response to the same instantaneous value of the output signal at the output terminal of the variable gain amplifier arrangement.

Abstract: A variable read output impedance control circuit of the present invention includes a variable impedance circuit as the output impedance of a magnetic media storage system. Preferably, the variable impedance circuit includes one or more diodes. The diodes are preferably coupled in series, to provide the output impedance of the magnetic media storage system. The impedance of the diodes is variable based on the amount of bias current that is provided to the diodes. The bias current is provided to the diodes from a current source preferably controlled by a controller circuit. By varying the amount of current provided to the diodes, the impedance of the diodes is adjusted. Accordingly, the read output impedance of the magnetic media storage system is controlled by controlling the bias current provided to the diodes.

Abstract: An information processing assembly includes at least one heater suitable for information processing, and a controller for controlling the at least one heater by at least one of adjusting a power to the at least one heater to match a target power level, and changing a polarity of an electrical current supplied to the heater.

Abstract: A write current circuit (40) adapted to drive a thin film write head (L0) of a mass media information storage device. The write current circuit includes a write current reference voltage circuit (42) adapted to selectively establish amplitude of a write current signal. The write current circuit further includes programming circuitry (M5-M10) driven such that several parameters of the write current waveform can be controlled, including the write current amplitude, overshoot amplitude and overshoot duration. The present invention achieves technical advantages by providing the ability to both produce an accurate write current, and also providing the ability to establish the write current waveform shape so that customers can optimize disk drive performance even when using different thin film write heads available from different suppliers.

Abstract: In a high-frequency impedance type magnetic head having high impedance and capable of efficiently detecting a change in impedance, an electrically conductive metal film is sandwiched between two soft magnetic films, and the two soft magnetic films form a portion of a magnetic path. The thickness of one soft magnetic film is smaller than the thickness of the other soft magnetic film. The electrically conductive metal thin film has a pair of electrodes at respective ends thereof, to which are connected an oscillator for applying a high frequency carrier signal to the electrodes and a high frequency amplifier having a demodulator circuit. Further, an electrically conductive metal film winding is provided, and a DC current is applied to the electrically conductive metal film winding at the time of reproduction, while on the other hand, a signal current is applied to the electrically conductive metal film winding at the time of recording.

Abstract: The present invention is a method and system to determine a quality of a head in a hard disk drive. The method comprises providing a disk having a at least one side with a plurality of tracks, writing on a predetermined track on the plurality of tracks and reading a profile of the predetermined track to provide a first profile value. The head is then moved to an adjacent track where it writes on the adjacent track. A profile of the predetermined track is then read to provide a second profile value. A quality of the head can then be determined based on the first and second values.

Abstract: The present invention is a method and system to optimize a write channel in a hard disk drive. The method comprises providing a disk having a at least one side with a plurality of tracks, and selecting a target track from the plurality of tracks. Data is written at least once on a predetermined plurality of tracks adjacent to either side of the target track and on the target track. Data is also written a predetermined number of times on tracks immediately adjacent to the target track. Data written on the predetermined plurality of tracks adjacent to either side of the target track and on the target track is then read. The process then determines if a number of errors on the tracks is greater than a predetermined criteria, if so, a write current value of the write channel is decreased, otherwise the write current value is increased.

Abstract: A system, method and computer program product provide an annealing process for setting a magnetization condition of a read head. An amount of heat for stabilizing magnetization condition of a read head is calculated. A width and amplitude of a voltage pulse that generates the calculated amount of heat in the read head are calculated. A voltage pulse of the calculated width and amplitude is applied to the read head for generating Joule heating in the read head. The width of the voltage pulse is less than one second.

Abstract: A recording/reproducing apparatus capable of switching over among a plurality of heads with high precision, wherein the apparatus is provided with: a recording/reproducing unit for recording/reproducing signals onto/from a recording medium with a plurality of heads; a generating unit for generating control data for controlling the recording/reproducing unit; and a transmitting unit for transmitting control data generated by the generating unit to the recording/reproducing unit, wherein priority is given in transmission to data for controlling the switching of the plurality of heads over other data.

Abstract: A self-vaccine as used herein will refer to methods of operating a disk drive and the apparatus implementing such methods, which make the disk drive immune to changes in temperature, that keep the disk drive healthy when hot or cold. The invention includes a self-vaccine extending the read channel optimization parameter database of a track zone or sequence to test temperature ranges actually found in the user's operation of the disk drive. The invention also includes the self-vaccine updating the read channel optimization parameter database for an already tested temperature range, whenever there has been sufficient time passed since the read channel optimization was performed for that temperature range. The invention includes read channel optimized parameters for at least temperature ranges within the embedded disk controller, which are updated in the user's operating environment during idle time providing the self-vaccine. The invention includes disk drives including a self-vaccine method.

Abstract: A disk driver writer precompensation system modulates the write current waveform based on a pattern of data bits magnetically recorded on a medium in order to adjust the timing of magnetic transitions recorded on the medium.

Abstract: A magnetic recording/reproducing apparatus is provided in which among diametrically oppositely disposed heads, a recording head and an erasing head of a same channel are disposed adjacently to each other. The recording head is disposed so as to precede by two tracks the erasing head with respect to a direction of cylinder rotation, when insert-editing, using a reproduced signal obtained by the recording head, erase and record timing setting and head tracking are performed and an erasing current is not applied during the reproduction by the recording head. The reproducing heads are disposed so as to be angularly apart by about 90 degrees from the recording and erasing heads, and a rotary transformer for reproduction is applied with a shield measure and then, formed as a core independently at an upper portion of the cylinder. In addition, more narrow tracks are compatibly reproduced by the recording head.