Abstract: A media storage device reads and writes data from and to a storage medium using a head and prevents in advance data loss due to thermal relaxation of data recorded on the storage medium. Table stores information which is related to a read error detected by a channel circuit in record units. The channel circuit measures information which is related to a read error and updates the information in the table. Further, data degradation is judged by this information which is related to the read error. Degradation of recorded data due to thermal relaxation can be detected accurately, and data loss can be prevented.

Abstract: A (e.g., hard-disk drive (HD)) system supports reader standby mode and/or writer standby mode. For reader standby mode, reader circuitry in the system's preamplifier is transitioned to a low-power mode during write operations. To provide quick transition from write mode to read mode, the reader circuitry is transitioned to pre-read mode before the end of the write operation. For writer standby mode, the preamplifier's writer circuitry is transitioned to a low-power mode during read operations. To provide quick transition from read mode to write mode, the writer circuitry is transitioned to a pre-write mode before the end of the read operation. The availability of a reader standby mode during write operations and a writer standby mode during read operations reduces power consumption as compared to HD systems that leave the reader circuitry in pre-read mode throughout each write operation and the writer circuitry in pre-write mode throughout each read operation.

Abstract: Embodiments of the present invention provide a magnetic disk drive system in which the write element leads the read element in the tangential direction of rotation of the magnetic disk. In addition, the servo sector information is preferably arranged such that information that is not needed for write operation is placed at the end of the servo sector. In this way, the servo read operation can be terminated sooner and the write operation can initiate sooner after going over the servo sector. The write element in a write operation writes data to the data sector of a track until an end of the data sector before reaching a front end of a servo sector following the end of the data sector. The read element reads information in the servo sector needed for the write operation. The write element starts writing data in a next data sector following the servo sector after the write element reaches the next data sector and after the read element has read all information in the servo sector needed for the write operation.

Abstract: Disclosed are a method and system for distinguishing spatial and thermal defects on perpendicular media. The magnetic domains of the perpendicular media are oriented to have a first polarity, scanned using a read head, oriented to have a second polarity and scanned again. The signals from the read head are combined to produce output signals having improved signal to noise ratios from which the locations of spatial and thermal defects can be identified and distinguished.

Abstract: A data storage device is disclosed with at least two partitions and a set of switches to separately enable and disable read and write operations to each of the partitions, wherein read and/or write operations for at least one of the partitions is disabled when the data storage device is accessible by one or more potentially malicious processes. In one embodiment, there are five partitions for (1) operating systems and trusted applications, (2) applications from non-trusted sources, (3) confidential data, (4) non-confidential data, and (5) all other data. A mode switch can be used to enable and disable reading and writing for each of the partitions according to a predetermined set of rules that effectively prevent viruses and other malware from altering or accessing programs and data.

Abstract: An information recording apparatus has a content encryption section which encrypts content information with an encryption key and outputs encrypted content information, a control section which identifies an already moved area in the content information and generates a reproduction enable condition containing reproducible area information indicating a movable area, a hash arithmetic device which executes hash calculation for the reproduction enable condition and stores an arithmetic result in a register, and a hard disk drive which records the encrypted content information output from the encryption section and the reproduction enable condition. Even content information that remains after interruption during movement can be moved.

Abstract: Embodiments of the invention provide a hard disk drive that is capable of performing degaussing promptly and properly and a recording method for use with such a hard disk drive. A hard disk drive according to one embodiment of the present invention comprises a current source for supplying a first current, which flows to a write head for writing data onto a magnetic disk; a current source for supplying a second current, which flows to the write head when the polarity of the first current changes; transistors for reversing the polarity of a current flowing to the write head; and a control circuit for exercising control so that the second current I2, which flows from the current source to the write head when the polarity of the first current I1 is reversed, becomes approximately zero before the first current I1 converges to approximately zero during a degauss period.

Abstract: Embodiments of the present invention provide a magnetic disk drive system in which the write element leads the read element in the tangential direction of rotation of the magnetic disk. In addition, the servo sector information is preferably arranged such that information that is not needed for write operation is placed at the end of the servo sector. In this way, the servo read operation can be terminated sooner and the write operation can initiate sooner after going over the servo sector. The write element in a write operation writes data to the data sector of a track until an end of the data sector before reaching a front end of a servo sector following the end of the data sector. The read element reads information in the servo sector needed for the write operation. The write element starts writing data in a next data sector following the servo sector after the write element reaches the next data sector and after the read element has read all information in the servo sector needed for the write operation.

Abstract: A plurality of recording media combined integrally having a plurality of recording surfaces; and a plurality sets of reading heads and writing heads, combined integrally, provided for the respective ones of the plurality of recording surfaces, are provided. Upon writing data on each recording medium with the writing head provided therefor, a writing position is controlled as a result of positioning information previously provided on the recording media including the recording medium other than the each recording medium being read with the reading heads provided therefor.

Abstract: An apparatus, method, and system for writing data to a hard disk drive synchronous with an apparent disk speed. The apparatus, method, and system has a phase-locked loop (PLL) to generate am output clock signal, wherein a clock interpolator responsive to phase rotation control is in the PLL feedback loop. The phase rotation control is proportional to the apparent disk speed, and the PLL output clock signal is also proportional to the apparent disk speed. A second clock interpolator further modifies the PLL output clock signal to provide pre-compensation control.

Abstract: Head-to-head variations in the head gap distance between write and read heads is compensated by measuring the head gap distance in each head by writing and reading a predetermined unique pattern, and compensating the timing to start the data writing by changing it in a head-to-head manner based on a time gap that corresponds to the measured head gap distance in each head. This allows data to be written at a desired physical position regardless of the variation of the head gap distance, thereby allowing formatting efficiency to be improved.

Abstract: A demagnetizer for an inductive load having a driver circuit including at least one transistor and a ramp-down voltage source switchably connected to the driver circuit, so that when the ramp-down voltage source is connected to the transistor, it drives the voltage of the transistor below its threshold voltage.

Abstract: The present invention provides a magnetic recording and reproducing apparatus, a magnetic recording and reproducing method, and a thin film magnetic head that enable a good contact between elements and a recording medium with a reduced track pitch even if the number of head channels is increased, thereby realizing high recording density and high transfer rate. At least one multitrack write head having N (N is an integer of 2 or more) write elements arranged along a track width direction in an integral fashion and at least one multitrack read head having L (L is an integer equal to or more than N) read elements arranged along the track width direction in an integral fashion are formed on the rotary drum. The multitrack write head writes signals to a group of N tracks aligned parallel on the magnetic tape during one rotation of the rotary drum, and the multitrack read head reads the group of N signal tracks by the use of any one of the L read elements.

Abstract: Demagnetizing magnetic media for recording data in a data storage device includes placing the magnetic media in a magnetic field at a first strength, and gradually reducing the magnetic field to a second strength to essentially eliminate net magnetization in the magnetic media.

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 writer for head positioning information, or a so-called servo track writer allows the read gap to follow a track which has been established on a recording medium or disk. As long as the read gap keeps following the existing track, the write gap is allowed to move along a path extending in parallel with the existing track. The write gap is utilized to write head positioning or servo information into the recording medium along the path. Even when the recording medium suffers from vibration or the like, the read gap can follow the track. The head positioning information can thus be written into the recording medium so as to establish a head positioning pattern at a higher positional accuracy.

Abstract: In order to generate a sampling clock having a higher accuracy, a synchronous signal generating circuit is provided with a phase error detector, detecting a phase error of a read out signal digitized on the basis of FDTS algorithm, and a VCO, controlling an oscillation frequency on the basis of a phase error detected by the phase error detector, to generate a synchronous signal by the VCO. On the basis of the synchronous signal generated by the synchronous signal generating circuit, an ADC digitizes the read out signal. The digitized read out signal is then converted to binary data by a detection circuit.

Abstract: The invention relates to a magnetic sensor utilizing a magnetoresistance effect, a method for driving a magnetic sensor utilizing a magnetoresistance effect and a magnetic recording system, and an object of the invention is to overcome the restriction in the level of sensitivity due to the upper limit of the sensing current that can be made to flow. A magneto resistive element 4 is connected to a portion of a feedback loop of a transistor 2 and an LC circuit 3 in an oscillating circuit 1 formed of transistor 2 and LC circuit 3, which is provided with a switching means 5 so that the reading rate of magnetic data is regulated by the switching frequency of switching means 5.

Abstract: Magneto-Resistive (MR) head read/write channel (400) provides timer (421), detector (433) and amplifier (432) to reduce the amount of time required to transition from read mode to write mode. Controller (410) issues the write command (WGATE) to signal a pending mode change from read to write mode. While read/write channel (400) remains in read mode, timer (421) begins a configurable countdown sequence, which allows Arm Electronics (430), except for a final output stage of amplifier (432), to power up in preparation for write mode. Once timer (421) has reached terminal count, signal (CHWGATE) is de-asserted, which causes write channel (422) to warm up. After warm up, write channel (422) writes serial data (WRITE DATA) to detector (433). Still in read mode, detector (433) detects the presence of WRITE DATA from write channel (422) and asserts signal (AEWGATE).

Abstract: A method and disc drive are disclosed that write servo wedges to a plurality of tracks of a disc. A head having a read element offset from a write element reads a servo wedge on a first track as a propagation guide and writes two or more servo wedges to be used as a subsequent propagation guide on a second track, all during one instance of a sector position of the disc rotating by the head. Additionally, a one of the written servo wedges can be radially continuous from the outer to inner diameter and is used for track-following during normal operation. In this manner, all radially continuous servo wedges for each sector of a given track can be written during one revolution of the disc, thereby reducing the amount of time necessary for servowriting.

Abstract: A cassette type audio signal recording apparatus comprising a recording detection sensor for generating a predetermined detection output as a recording button is pressed, a recording head for converting the applied magnetic signal to an electric audio signal and outputting the converted signal, an A/D converter for converting the audio signal output from the recording head to a digital signal, a memory for recording digital type audio data, a recording controller for controlling the encoding of the digital data converted by the A/D converter based on the detection output generated by the recording detection sensor and for storing the encoded data in the memory, and a power supply portion for supplying power to each of the components, wherein the outer shape thereof has the same size and shape as that of a cassette tape.

Abstract: Head-to-head variations in the head gap distance between write and read heads is compensated by measuring the head gap distance in each head by writing and reading a predetermined unique pattern, and compensating the timing to start the data writing by changing it in a head-to-head manner based on a time gap that corresponds to the measured head gap distance in each head. This allows data to be written at a desired physical position regardless of the variation of the head gap distance, thereby allowing formatting efficiency to be improved.

Abstract: In order to generate a sampling clock having a higher accuracy, a synchronous signal generating circuit is provided with a phase error detector, detecting a phase error of a read out signal digitized on the basis of FDTS algorithm, and a VCO, controlling an oscillation frequency on the basis of a phase error detected by the phase error detector, to generate a synchronous signal by the VCO. On the basis of the synchronous signal generated by the synchronous signal generating circuit, an ADC digitizes the read out signal. The digitized read out signal is then converted to binary data by a detection circuit.

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: The present invention relates to a signal recording and reproducing method used for video tape recorder. An erasing position precedes a recording position and a reproducing position precedes the erasing position. By using a period when reproducing does not reproduce a signal recorded on a track of a tape-like storage medium, the period occurring during recording and reproducing operation, recording apparatus records a signal on a recording track or erasing apparatus erases a signal recorded on a recording track. Hereby, if a signal recorded on a recording track of the tape-like storage medium is processed and replaced, the signal recorded on the recording track of the tape-like storage medium can be satisfactorily reproduced without being influenced by signal recording operation and signal erasing operation.

Abstract: This invention provides a read/write channel with a multiplex input/output system for a disk drive, which may have one or more magnetic disks, one or more read/write heads, and a read/write channel. The read/write channel may comprise a multiplex input/output (I/O) terminal, a write output driver, and a digital to analog converter. The read/write channel may be implemented on an integrated circuit. The multiplex input/output system may send different signals or voltages through the same input/output terminal at essentially at the same time or different periods of time.

Abstract: A magnetic disk drive system having a write head Hw and a read head Hr which can move over a magnetic disk in a radial direction of the disk and are arranged at a distance from each other. At a predetermined write start timing tWG, it writes measurement information by the write head in a specific sector at a first timing tW, then reads the information by the read head, detects predetermined positional information included in the information, and produces a second timing tDA. The system subtracts the interval between the second timing and the start timing from the interval between the first timing and second timing to measure the write/read head distance time difference in the track direction of the magnetic head unit. The write/read head distance information is used for correction and control of the operation of the magnetic head unit.

Abstract: One aspect of the invention is a digital audio tape (DAT) drive having a plurality of read and write heads. Each of the read and write heads has its own parameters, such as a cut-off frequency and a boost value of a read head, a write current of a write head, etc. The parameters of each head are stored in registers and used when an electrical signal representing digital data is to be written to or read from a magnetic tape is processed. When the electrical signal to be written or to have been read by a specific head is processed, the parameters of the specific head will be provided to an equalizer or a pre-amplifier. In the reading process, because the optimum cut-off frequency and boost value are used for a specific read head, the processed electrical signal more accurately represents the digital data recorded on the magnetic tape. In the writing process, the optimum write current to a specific write head makes the write head generate a sufficient magnetic field to magnetize the write head.

Abstract: In a magnetic recording device, a control element placed on a flexible wiring board between a control device and first actuators includes a plurality of actuator-driving-signal connecting terminals connected to a plurality of second actuators, an actuator-driving-signal input terminal to which driving voltage for the second actuators is input from the control device, connecting wires for connecting the actuator-driving-signal input terminal to the actuator-driving-signal connecting terminals, signal selection elements incorporated in the connecting wires, and a decoder for selecting one of the signal selection elements so that a specific actuator-driving-signal connecting terminal is connected to the actuator-driving-signal input terminal.

Abstract: A magnetic disc apparatus according to the present invention is one which is provided with a host interface unit 2 which controls the interface connected to a host apparatus 1, a command administrating unit 3, a position information administrating unit 4, a control unit 5 which controls the whole operation of a magnetic disc apparatus 9, a buffer memory 6 which temporarily stores data, a read/write control unit 7 and a magnetic disc 8. The magnetic disc apparatus thus constituted can enhance the data transmission efficiency even when accessing to plural systems of large capacity successive data are carried out.

Abstract: Methods and apparatus for increasing the density of data storage on a magnetic medium by using variations in positioning of magnetic transitions to encode bits. Conventionally encoded bits are written to the medium as sequences of magnetic transitions according to an encoding standard. Additional bits are encoded on the medium as deviations from a nominal position of magnetic transitions separating conventionally encoded bits. The deviation from the nominal position is within an allowable range of tolerance for the standard followed in encoding the conventionally encoded bits. In order to prevent accumulation of error, additional bits are only encoded in transitions separating a pair of conventionally encoded bits. The first and last transitions of the pair do not have additional bits encoded as deviations of transition locations. This technique allows the encoding of one additional bit for every two conventionally encoded bits.

Abstract: A reproducing apparatus for reproducing an information signal recorded on a recording medium is provided with a reproducing part arranged to reproduce the information signal recorded on the recording medium and to output the reproduced information signal, a muting circuit for muting the information signal outputted from the reproducing part, a detecting circuit for detecting the level of a noise component included in the information signal outputted from the reproducing part, and a control part for controlling a muting action of the muting circuit on the basis of a result of detection provided by the detecting circuit. These parts in combination enable the reproducing apparatus to reproduce the information signal without generating any noise component, in a minimal length of time after the commencement of reproduction.

Abstract: An offset circuit to correct an offset between differential signals includes a read circuit to read the differential signals, a circuit to measure the offset of the differential signals, and a programmable trim circuit to compensate for the offset of said differential signals.

Abstract: A writer for head positioning information, or a so-called servo track writer allows the read gap to follow a track which has been established on a recording medium or disk. As long as the read gap keeps following the existing track, the write gap is allowed to move along a path extending in parallel with the existing track. The write gap is utilized to write head positioning or servo information into the recording medium along the path. Even when the recording medium suffers from vibration or the like, the read gap can follow the track. The head positioning information can thus be written into the recording medium so as to establish a head positioning pattern at a higher positional accuracy.

Abstract: The present invention includes a circuit which can achieve a 200 nano second write to read time. The present invention eliminates a switch in the RMR measurement circuit.

Abstract: A method for writing and reading data in a hard disk drive and compensating for an offset between a write element and a read element of a head. The method determines an offset time by determining the difference between a desired sync byte position and an actual sync byte position located between a preamble and a data sector of the disk. The difference corresponds to the offset between the read and write elements. The offset time is subtracted from the normal time for enabling the read gate of a disk drive pre-amplifier.

Abstract: Multi-head disk drive system measures head resistances and selects lowest-resistance heads for track-servo operation during sleep mode, thereby substantially prolonging EM lifetime, improving field failure rate, unit production costs, and drive performance and yields.

Abstract: A method and disc drive are disclosed that write servo wedges to a plurality of tracks of a disc. A head having a read element offset from a write element reads a first servo wedge on a first track as a propagation guide and writes a second and third servo wedge to be used as a subsequent propagation guide on a second track, all during one instance of a sector position of the disc rotating by the head. Additionally, a fourth servo wedge that is radially continuous from the outer to inner diameter is also written for each sector of the track during the revolution and is used for track-following during normal operation. In this manner, all radially continuous servo wedges for each sector of a given track can be written during one revolution of the disc, thereby reducing the amount of time necessary for servowriting.

Abstract: A rotary magnetic head apparatus is provided which can be formed into a small size even if a plurality of reproduction heads are provided.

Abstract: In an information signal recording and reproducing apparatus, reproduced data is equalized by an equalizer and a clock signal synchronized in phase with the reproduced data is generated. An equalizing characteristic of the equalizer is controlled according to a difference in frequency between the clock signal and the reproduced data, and a generating operation for the clock signal is controlled according to a phase difference between the clock signal and the reproduced data. The clock signal thus can be stably generated without being affected by variations of temperature and variations due to aging. The equalizer thus has an adequate equalizing characteristic. The apparatus includes a recording mode and a reproduction mode. In the recording mode, a recording clock signal is generated by a clock signal generating circuit and a digital signal is recorded by using the recording clock signal.

Abstract: A tape recording and playback unit records and reads back data from tape either in a high track density standard format or alternatively reads back data from a tape previously recorded on another unit in accordance with a previous low density standard track format. The unit includes a primary head positioning mechanism for positioning a primary multi-channel write/read head and a secondary head positioning mechanism for positioning a secondary read-only head. The secondary head may be positioned angularly to read longitudinal and azimuth track patterns, and also to be retracted when not needed.

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: In a magnetic recording device, a control element placed on a flexible wiring board between a control device and first actuators includes a plurality of actuator-driving-signal connecting terminals connected to a plurality of second actuators, an actuator-driving-signal input terminal to which driving voltage for the second actuators is input from the control device, connecting wires for connecting the actuator-driving-signal input terminal to the actuator-driving-signal connecting terminals, signal selection elements incorporated in the connecting wires, and a decoder for selecting one of the signal selection elements so that a specific actuator-driving-signal connecting terminal is connected to the actuator-driving-signal input terminal.

Abstract: The present invention includes a circuit which can achieve a 200 nano second write to read time. The present invention eliminates a switch in the RMR measurement circuit.

Abstract: A magnetic read-write device with a magnetic head consisting of a core and a coil. The read-write device is incorporated into in a camera. A writing circuit is connected directly and in parallel to the coil, for driving the coil with writing current in a writing mode for writing binary code data on a magnetic recording layer provided on photo film. The writing circuit has a pair of write control switches which are turned ON and OFF alternately to each other, to apply the writing current to the coil in alternating directions. An amplification circuit is also connected directly and in parallel to the coil. The amplification circuit amplifies signal voltage induced between terminals of the coil in a reading mode for reading binary code data from the magnetic recording layer, to output a reproduction signal. A switching transistor is connected in a line through which a drive voltage is supplied to the amplification circuit.

Abstract: An apparatus for substantially eliminating a switching voltage transient in a magnetic recording system so as to minimize a write-to-read recovery time includes a first bias enable switch, a bias current source responsive to the first bias enable switch, an MR sensor for receiving a bias current from the current source, and a read amplifier being capacitively coupled to the MR sensor. The bias current flowing through the MR sensor produces the switching voltage transient due to the RC time constant presented by the input of the read amplifier. The apparatus includes a first compensating circuit for generating a compensating voltage transient having a polarity substantially equal and opposite to the switching transient. The first compensating circuit is electrically coupled to the MR sensor, and a superposition of the switching voltage transient and the compensating voltage transient is substantially zero.

Abstract: A tape recording and playback unit records and reads back data from tape either in a high track density standard format or alternatively reads back data from a tape previously recorded on another unit in accordance with a previous low density standard track format. The unit includes a primary head positioning mechanism for positioning a primary multi-channel write/read head and a secondary head positioning mechanism for positioning a secondary read-only head. The secondary head may be positioned angularly to read longitudinal and azimuth track patterns, and also to be retracted when not needed.

Abstract: A magnetic disk device of embedded-servo type is capable of performing dummy operation for suppressing waveform degradation of signal reproduced by magnetic heads at a high speed with high reliability. When a waveform deformation occurs in a No.0 head, a controller changes over the No.0 head to a No.1 head operating normally, whereupon a cylinder portion for which dummy operation is to be performed is sought on the basis of the servo information supplied from the No.1 head. The cylinder portion destined for the dummy write operation contains servo information at timing positions that are the same for the individual magnetic heads. When passing of the No.1 head over the cylinder portion is confirmed, the No.1 head is changed over to the No.0 head for performing dummy write operation for suppressing the waveform deformation of the reproduce signal outputted from the No.0 head. Before the timing for succeeding information, the No.1 head is restored by issuing a head change command signal.

Abstract: A magnetic recording and regenerating unit for photographic film and a camera, which feed photographic film coated with a magnetic recording layer, records magnetic information in the magnetic recording layer, and regenerates magnetic information from the magnetic recording layer. In the magnetic recording and regenerating unit for a camera, the number of turns of a coil wound around a core included in a magnetic head is small. Thus, one magnetic head is able to record and regenerate magnetic information. The number of turns of the coil is determined so as to output a regenerated waveform which does not enable reading of the magnetic information but permits determination of whether any magnetic information is recorded or not. Whether any magnetic information is recorded or not is determined based on the output voltage from a smoothing circuit, a peak hold circuit, etc. which receive signals output from the magnetic head via an amplifier.

Abstract: In a recording support mode, states of an HD device and a VTR are detected, and if the two are normal, video signals are recorded in both. The signal recorded in the HD device can be reproduced almost simultaneously with the recording upon request. Where either device is abnormal, the video signal is recorded in the normal device. In the reproduction support mode, the reproduction position of the HD device is detected, the VTR video tape is brought to that position, it is checked whether or not the video signal the same as the video signal which has been reproduced by the HD device is recorded based on the time code of the video signal recorded at that position, and the reproduction of the same video signal is carried out simultaneously with the HD device. Thereafter, where an abnormality occurs in the HD device, a third switch is changed over so that the video signal reproduced at the VTR is output.