Abstract: An apparatus configured according to characteristics for driving a write head to write to a memory device includes: (a) a current directing circuit directing a write current through a first circuit path or a second including the write head in response to a first or second write signal; (b) at least one of: (1) an impedance system for including at least one impedance unit within each of the first and second current paths; and (2) a current system for including at least one circuit element between a locus at each end of said write head and a supply voltage; and (c) a control unit coupled with at least one of the impedance system and the current system for effecting the including for at least one of the impedance system and the current system to effect configuring the apparatus.

Abstract: A method and apparatus are provided for implementing in situ low flyheight warning in a direct access storage device (DASD). For each head in the DASD, a readback amplitude ratio is identified from two different disk radii. The initial ratio value is stored for each head in the DASD. During operation of the DASD, readback amplitude is monitored and an operating readback amplitude ratio is identified from two different disk radii. A change between the initial ratio value and the operating readback ratio is calculated and compared with a threshold value to identify a low-flying slider. A warning is generated responsive to the change value being greater than the threshold value.

Abstract: A method of performing an accurate magnetic transfer to a high-density slave medium having two magnetic layers and utilizing antiferromagnetic coupling. The magnetic layer, which has been initially magnetized in advance, of a magnetic recording medium is conjoined with the data bearing surface of a master medium. A transfer magnetic field is applied to the conjoined body in the circumferential direction of the track of the first magnetic layer in the direction opposite the initial magnetization direction of the second magnetic layer. At this time, the thickness of the magnetic layer of the master medium, the permeability (material) of the magnetic layer, the form of the patterned magnetic layer, the separation distance between the master medium and the magnetic recording medium, etc., may be controlled so that the magnetic field of the transfer magnetic field does not effect the magnetization state of the first magnetic layer.

Abstract: A favorable magnetic transfer is performed on a perpendicular magnetic recording medium. A permanent magnet apparatus provided with two permanent magnets, each having a width extending the length of the radial direction of a discoid magnetic recording medium, is used as a transfer magnetic field generating means. A conjoined body formed of the perpendicular magnetic recording medium, which has been initially magnetized unidirectionally in the direction perpendicular to the track surface thereof, and two master mediums, disposed on respective surfaces of the slave medium, is inserted between the permanent magnets. A rotating means rotates the conjoined body, in the direction along the tracks of the slave medium, while a transfer magnetic field is applied to the conjoined body in the direction substantially opposite that in which the initial magnetization of the magnetic layer of magnetic recording medium has been performed, so as to perform the magnetic transfer.

Abstract: Within a casing accommodating members for performing magnetic transfer of signals from one medium to another, a plurality of suction ports are fixedly disposed at various locations. Resin tubes connect the suction ports to respective particle counters for the measurement of particles at each location, whereby the source of particles is locatable.

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: A procedure for estimating bit error rate (BER) for disc media in a disc drive is disclosed. Initially, the BER estimation procedure writes random data to specified tracks on the disc media. The procedure then reads the specified tracks over predefined time intervals to determine a BER for the disc media at the termination of each interval. Using the determined bit error rates, the procedure extrapolates the BER values to generate a decay graph representative of a BER slope over the time period comprising the time intervals. The decay graph is then used to estimate BER for the disc media at a predetermined time, such as the end of the expected life of the disc drive.

Abstract: A system and method for recovering from write errors during writing of a moving storage medium suspend write current while allowing the storage medium to continue moving. The system and method continue to format data for writing while the write current is suspended and resequence the data for subsequent storage. Information is recorded to distinguish previously written data from current data with error correction pointers adjusted accordingly. Write errors may be detected in a track following streaming tape system based on data errors from a read back check or based on positioning errors of a read/write head servo system, for example. By allowing the storage medium to continue moving through the error event, the system and method improve speed, capacity utilization, and throughput of the storage and retrieval process.

Abstract: In an apparatus for reading recorded data, the apparatus, a read signal is sampled from recorded data of a recording medium by synchronizing with a first clock signal. A sample value obtained by the sampling part is stored and also the sample value from the first storing part is retrieved by synchronizing a second clock signal different from the first clock signal and maximum likelihood data is detected by processing the sample value in accordance with a predetermined algorithm. The recorded data is read based on the detected data.

Abstract: An information recording medium, an information recording/reproduction head, and an information storage device are provided for performing a track servo operation at a smaller track pitch than that conventionally used without reducing the widths of servo burst patterns. The widths of servo burst patterns (107, 108, 109, 110) are increased over a track pitch (TP) and the end of the servo burst pattern is disposed so as not to coincide with a center line (111) of an information track. In addition, a servo magnetic head (112) and a reproduction magnetic head (113) are implemented in one magnetoresistance element (159).

Abstract: A disk unit, such as a magnetic disk unit, has a temperature sensor, a humidity sensor, a heater, a Peltier element, etc. The disk unit heats and cools in accordance with temperature and humidity. The disk unit has a double-structure of outline comprising a first outline and a second outline surrounding said first outline, so that an internal environment is isolated from an external environment.

Abstract: A system and method for measuring the fly height of a head flying over a disc in a disc drive is disclosed. A head is vertically spaced from a rotating disc surface by an air bearing surface. The disc has one or more radial grooves in the surface of the disc. As the disc rotates, the radial grooves on the disc pass under the head and induce a perturbation in the signal. By measuring the perturbations in the signal caused by the grooves in the disc surface, and by processing the measurement signal, a vertical spacing signal proportional to the vertical spacing between the disc and the head can be obtained.

Abstract: There is disclosed a method of accurately locating an append point along a length of linear tape data storage medium, comprising entering a search mode searching for an absolute code word quad set number, and having found the absolute code word quad set number, entering an interrupt mode for control of tape transport, followed by a write mode to write data at a data set containing the absolute code word quad set number.

Abstract: The present invention aims to perform high-accuracy focus control in an optical disk drive, even if a solid immersion lens (SIL) or a solid immersion mirror (SIM) is set between an objective lens and the optical disk in order to increase a numerical aperture, by accurately detecting a change of the distance between an SIL or SIM and an optical disk. The present invention comprises light detection means (8) for detecting the light incoming to an SIL (2) or an SIM from an objective lens (1) at an incidence angle at which a numerical aperture is larger than 1 and reflected from a plane of the SIL (2) or SIM facing an optical disk, light detection means 10 for detecting the light incoming to the objective lens (1), comparison means (11) for finding a ratio between light amounts of the light detected by light detection means (8) and (10), and control means (11) for controlling operations of a focus actuator in accordance with the ratio.

Abstract: Systems and methods for reading information stored on a magnetic medium are described. Data symbols are generated from a signal encoded at a baud rate with data including an acquisition preamble defining an acquisition frequency and an acquisition phase. The system includes an inventive dual loop synchronizer that is optimized to improve the operating efficiency and reduce the overall latency of the read channel. In one aspect, the dual loop synchronizer includes a frequency synchronization loop, a signal sampler, an interpolator, and a phase synchronization loop. The frequency synchronization loop is configured to generate a sampling clock synchronized approximately to the acquisition frequency and the acquisition phase of the encoded data signal. The signal sampler is coupled to the frequency synchronization loop and is configured to sample the encoded data signal in response to the sampling clock to produce a plurality of data samples.

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: A reproducing apparatus and method, the method comprising the steps of comprising recording a plurality of files and number-of-reproduction-times limitation information thereof, selecting a desired file from the plurality of files stored in the memory, and comparing whether the number-of-reproduction-times limitation information allows for reproduction of the selected file. The method further comprises the steps of counting the reproduced elapsed duration of the selected file and comparing whether the reproduced elapsed duration exceeds a predetermined value. The number-of-reproduction-times limitation information stored in the memory is edited when the reproduced elapsed duration exceeds the predetermined value to reduce the number of times the selected file may be subsequently be reproduced.

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 method and a device enters a test mode in a floppy disk drive integrated circuit. The method and device includes a monitoring circuit and an integrated circuit having a selecting circuit. The selecting circuit selects a test-mode when a test mode command is received and a steady state voltage level is reached in a predetermined time period.

Abstract: To make the most of the storage capacity of a recording medium for data recording and reproduction, data is provisionally stored in a memory at a second data rate DL2, then data is read from the memory at a first data rate, and the recording medium is driven intermittently according to a change in data rate.