Abstract: A magnetic disk drive includes redundant data written at a plurality of out of phase angular locations to reduce the latency and enhance performance during a read operation. The loss of recording capacity is reduced by increasing the data density to achieve the same soft error rate standard required for single recording. Dual recording also allows different recording codes to be used at the duplicated locations to thereby have the more highly stressed code words occur at different locations in the data to further reduce the possibility of an error. The redundant recording can be used in one portion of the media and normal recording used in another media portion to enable selection of the recording technique in accordance with the type of data being stored. The size of the normal and redundant recording portions can be controlled by the format operation and the user of the disk drive can intervene to designate the size of the redundant and normal media recording portions effected during the format operation.

Abstract: A recording apparatus has a check-after-write function for reproducing and checking the recorded state of a recorded track. When overwriting of data is started, an identification number to be stored in a track is set at a fixed value, and check-after-reproduction is performed by the fixed value during reproduction in which a check is made. Also, a reproducing apparatus includes a system for detecting that a very small error segment has occurred on the data and for making the data of the error segment invalid or not outputting the data when it is determined that the error segment has occurred.

Abstract: An object of the present invention is to minimize an overhead attributable to internal control and to provide a CDR type disk unit in which even when a head moves over a zone boundary, a sector pulse indicating a destination sector can be generated reliably without waiting for an index pulse. The disk unit includes a processing unit; a sector pulse generation unit which generates a sector pulse according to a signal written in the servo information on medium surface; and a format control unit which starts the formatting control when said sector pulse is received after a activating command is received from said processing unit; a target sector detection unit which detects the instant when said head reaches the target sector. The sector pulse generation unit stops outputting the sector pulses to the format control unit from when the access operation starts until a target pulse is received from the target sector detection unit.

Abstract: A recording and reproducing apparatus can translate a detecting device for detecting information, such as the kind and content of tape cassette and a reel lock mechanism releasing device to proper positions corresponding to tape cassettes of different sizes. A tape cassette information detecting device (71) and reel lock releasing device (72a, 72b) can be translated to positions at which large and small tape cassettes are in use through a swing drive member (54), a translating lever (73), a driving link (74), a detection mechanism holding member (75) and a reel lock releasing plate (77) in unison with a movement of reel mounts (44, 45).

Abstract: A lone precoder of 2T type generates interleaved non-return to-zero, invert-on-ONEs (I-NRZI) modulation for digital signal recording apparatus used for recording in parallel tracks on a record medium, the interleaved codes providing for the inclusion of pilot signals in selected sets of recording tracks. A first set of NRZI codes is generated directly by the precoder, and a second set of NRZI codes is generated by bit-complementing odd bit places of the first set of NRZI codes. Preferably the lone 2T precoder is one that performs its coding of each information word on a parallel-bit basis, to implement pipeline processing of the generation of I-NRZI modulation, and to avoid the need for intermittently written or intermittently read buffer storage. The digital signal recording apparatus is suited for the recording of television signals, with pilot signals being included on the tracks when sync and run-up data are recorded, as well as when video and audio data are recorded.

Abstract: A servo gate method and apparatus to allow switching between a servo mode and a data mode in the read channel of a disk drive. The present invention uses a servo gate signal to select components and parameters in the read channel of a disk drive. The servo gate signal, when enabled, preloads appropriate registers with new values and preloads the programmable filter with new values. The servo gate signal is not limited to preloading the above values, but may be used to control many characteristics of a disk drive read channel.

Abstract: Input digital data are formatted into a data block composed of a predetermined amount of data, subjected to error correction encoding process, and recorded on a predetermined number of continuous tracks of a recording medium. In the error correction encoding process, the data block is subjected to an inter-track error correction encoding, an outer error correction encoding and an inner error correction encoding. In the inter-track error correction encoding, each information element to be coded is produced by symbols collected from the data which are to be recorded on different tracks of the continuous tracks. The error correction encoded data in the data block are distributed to a first predetermined recording area of each track of the continuous tracks, and parity code words produced by the inter-track error correction encoding are distributed to a second predetermined recording area of each track of the continuous tracks.

Abstract: There is used a disk medium in which tracks are divided into a plurality of zones in the radial direction and information is read and written with a constant linear density by using a clock signal of a different frequency every zone. A drive unit forms a dead space corresponding to at least one track at a zone boundary of the disk medium and reads or writes the information. In the case where it is judged that the head passes through the zone boundary by the seeking operation to the cylinder address position instructed from an upper apparatus, the cylinder address instructed from the upper apparatus is corrected on the basis of the number of boundary passing times and the seeking operation is performed.

Abstract: A magnetic disk storage apparatus provides with a phase locked loop or a phase sync circuit including a phase comparator, a charge pump, a filter and a voltage-controlled oscillator. The phase sync circuit includes a register which is connected to an information processing system and adapted to store therein the response characteristics of the phase comparator, the charge pump, the filter and the voltage-controlled oscillator as instructed from the information processing system. In this way, in accordance with the information on the response characteristics from the information processing system, the phase sync circuit is controlled thereby to assure a stable operation even in the case of the data transfer speed varying between inner and outer track such as occurs in a magnetic disk.

Abstract: An apparatus for the adaptive cancellation of at least a first pole frequency in a magnetoresistive (MR) head device includes a preamplifier coupled to first and second terminals of the MR head. A signal at a pole frequency produced by the preamplifier is cancelled by a zero boost frequency signal generated as a result of a signal across the MR head read by a differential amplifier. The zero boost frequency signal is passed to the read channel coming from the MR head to cancel the pole.

Abstract: The present invention overcomes the problems that accompany the use of ramps to load and unload transducer carrying sliders in rigid magnetic disk data storage devices. The tracks in the region where the slider loads and unloads are read and the errors recorded following each slider loading operation. One technique is to track the error increase and identify imminent device failure when the rate of error increase during a given number of the most recent slider load cycles exceeds a threshold value. In another mode, a dedicated sequence of tracks is recorded at an increased linear density to assure that read errors occur to enable a more effective comparative evaluation. This makes possible a two stage evaluation, a first threshold number of errors indicative of degrading performance which initiates lower actuator velocity to inhibit further degradation and a second threshold error quantity that indicates imminent catastrophic failure and triggers a warning to the system user.

Abstract: A magnetic disc apparatus employing a constant-density recording type and a magnetic disc driver for accessing data thereon. The magnetic disc apparatus comprises a plurality of tracks extended in a circumferential direction on the magnetic disc apparatus surface; a plurality of servo and data information areas which are provided in the circumferential direction of each track; a WID (wedge identification) field for recording the ID for data sectors positioned in one data information area, the ID being recorded in only one interval for each data information area; and a PID (pseudo identification) field positioned in front of each data sector and having an interval corresponding to transfer time of the PID (i.e. the ID of a corresponding data sector) generated from a WID field during access of the magnetic disc apparatus.

Abstract: A magnetic-tape apparatus with a rotary scanning device in which a plurality of magnetic heads are mounted at the circumference and are associated with rotating amplifiers, which for the signal transfer are connected to stationary devices at a stator side via respective rotary transformers. The stator side of the rotary scanning device includes a generator for the generation of a phase-data signal including a periodically recurring pulse sequence bounded by synchronization pulses (S) and comprising between the synchronization pulses a bit-serial sequence of pulses whose pulse edges time the transfer of the signals from and to the magnetic heads. A feedback register circuit at the rotor side derives various timed head-switching signals for turning on/off the rotating amplifiers from an optically transmitted phase-data signal.

Abstract: There is provided a recording/reproducing apparatus, e.g., digital video tape recorder, etc., applicable to a transmission system sufficiently utilizing communication capacity. The recording/reproducing apparatus comprises a recording element (e.g., rotary head) for recording, onto a recording medium (e.g., magnetic tape), time base compression processing implemented digital data delivered from the external, e.g., broadcasting station side, etc.; a control circuit for carrying out a control to read out the digital data from the recording medium at a speed lower than a recording speed in dependency upon the time base compression processing implemented to the digital data; and an output circuit for outputting, as a reproduced output, digital data which has been read out from the recording medium.

Abstract: A method and apparatus for determining the position of a head with respect to a rotating magnetic disk within a disk data storage device using standard signals output from a head/drive assembly (HDA). Servo zone detect pulses are used to determine the position of the read/write head with respect to the servo cells. An index pulse determines the angular position of the head. A servo zone counter is incremented by one in response to a servo zone detect pulse. Accordingly, the servo zone counter maintains a unique value which is corresponds to each data wedge on a surface of the disk. A servo clock has a constant number of cycles between sectors. The servo clock is coupled to the clock input of a sector counter. A sector pulse is generated and the sector counter is reset to zero when the number of cycles counted indicates that the beginning of a sector is under the read/write head. A sector ID counter counts the number of sector pulses.

Abstract: The method and apparatus records/reproduces multiple kinds of digital signals having different data amounts per unit time on a recording medium. The multiple kinds of digital signals are organized into a plurality of blocks. At least two of the multiple kinds of digital signals are organized into blocks having different lengths. A synchronizing signal is appended to each of the plurality of blocks. The synchronizing signal identifies a length of each of the plurality of blocks. This method an apparatus increase the recording rate, and is therefore suitable for higher density recording. In reproduction, synchronization protection is performed for variable synchronization periods based on the length of the blocks being reproduced.

Abstract: A signal reproducing circuit includes: a magneto-resistive effect head having one end thereof coupled to a first power supply line, for reproducing data recorded on a magnetic recording medium in a read operation; a first constant current source coupled between another end of the head and a second power supply line, for supplying the head with a sense current in the read operation; first and second transistors having collectors thereof coupled to the first power supply line, and responsive to voltage signals obtained from both ends of the head; second and third constant current sources coupled between each emitter of the first and second transistors and the second power supply line, for supplying the first and second transistors with a predetermined constant current in the read operation; a capacitor connected between each emitter of the first and second transistors; and a control circuit responsive to a read/write control signal, for controlling respective ON/OFF timings of the first to third constant curren

Abstract: A filter for compensating discrete secondary pulse formations associated with a data stream of discrete main pulses produced from data read from magnetic media. The filter's impulse response comprises a center coefficient with side compensating coefficients for attenuating the secondary pulses when the input signal is convolved with the impulse response. The magnitude and delay of the compensation coefficients are programmable and are adaptively adjusted to optimize the impulse response for a given environment. In a traditional FIR embodiment, two delay lines are used to generate the two programmable delays between the center coefficient and side compensation coefficients. In the preferred embodiment, an IIR filter provides the two programmable delays using only one delay line thereby reducing the size and cost of the circuit. Also in the preferred embodiment, the data stream is interleaved into an even and odd data stream and processed in parallel by two filters in order to double the throughput.

Abstract: A digital magnetic recording system comprises an input for a binary-encoded data signal comprising two symbols. The binary signal is converted, using a binary-to-ternary convolutional encoder, to a ternary signal comprising three symbols. The ternary signal is recorded onto a magnetic medium wherein two symbols are recorded using conventional saturation recording and a third symbol is recorded using a nonoriented state. The nonoriented state results from the application to the medium of a high-frequency oscillating magnetic flux. The recorded signal is subsequently reproduced and equalized. A Viterbi algorithm is used to convert the equalized signal back to the original binary signal which is then output from the system.

Abstract: A method is described which provides various new data storage system capabilities by using data storage structures within industry standard (or other pre-existing) formats used with data recording devices employing removable media. The data storage structures used by the present method comprise formats which contain regions previously marked as "contents of this region are not of interest" or marked as "no data was recorded within this region". These data storage structures are thus transparent to present data recording devices so as not to disrupt their data processing functions. However, the data storage structures are available to be used by new data recording devices (or old devices that have been updated) so that new data embedded therein may be used to enhance the functionality of the system which utilizes the data storage structures.