Abstract: A decoding circuit has a nonlinear equalizer which employs a signal conditioning algorithm for conditioning a partial response sampled signal to eliminate intersymbol interference. The inventive decoding circuit has an analog-to-digital converter for sampling an analog signal, a linear equalizer for adjusting the amplitude and phase relations of the sampled signal, a nonlinear equalizer for conditioning the sampled signal and outputting a partial response sampled signal having two nonzero samples, and a partial response maximum likelihood detector, for detecting the partial response sampled signal having two nonzero samples.

Abstract: A method and apparatus for detecting a high fly write event in a computer disk drive is provided. The method and apparatus allow the detection of high fly write events occurring over very short time spans. In addition, the present invention provides a method and apparatus for detecting high fly write events with a great deal of sensitivity. The method and apparatus of the present invention provide quick response and high sensitivity by monitoring the strength of a signal derived from a servo sector position burst or a group of bursts, and signaling a high fly write event if the monitored signal strength is less than a predetermined or threshold amount.

Abstract: A method of encoding a digital data stream for writing to a digital storage (DDS) format tape data storage medium comprises writing a byte stream to a preamble region, immediately preceding a user data region. The byte stream has a power spectrum substantially similar to a power spectrum of the user data region. An automatic gain control circuit responds to the preamble data stream in a substantially similar fashion to its response to the user data stream.

Abstract: A disc drive device includes a base and a disc rotatably attached to the base. The disc drive also includes an actuator assembly rotatably attached to said base and a device for moving the actuator assembly. The actuator assembly includes an actuator arm and a transducer head in a transducing relationship with respect to the disc. The transducer is attached to the actuator arm. A method of screening disc drives for harmonic resonant frequencies includes sampling the position error signal at a track location in the disc drive, and determining the velocity of the position error signal from the sample of the position error signal. The velocity of the position error signal sample is divided by the position error signal to produce a quotient. The quotient is compared to a selected quotient threshold value to determine the type of a harmonic in the disc drive.

Abstract: A method (and magnetic recording circuit structure) for write drivers to reduce the reversal time for the current through the inductive recording head, includes a write driver output stage providing a write signal output with a write signal source strength SO, a magnetic write head with a write signal input essentially equal to strength SO, and an interconnect circuit having a characteristic impedance ZO coupled to the write signal output of the write driver output stage and the magnetic write head. The write driver output stage preferably includes a source-side termination circuit having output impedance ZS, wherein the source-side termination circuit output impedance ZS is substantially equal to ZO and the source strength SO of the write driver at the input of the interconnect circuit is temporarily enlarged after every polarity reversal of the write signal for a predetermined time duration &Dgr;t.

Abstract: Embodiments of systems, methods and article of manufacture provide for readback signal detection and analysis. One embodiment provides an in-situ system to detect envelope traces of a readback signal. Using the envelope data, the presence of undesirable activity and/or storage medium surface conditions may be determined. For example, head modulation may be determined. Upon detection of a modulation event in a sector or a track, the compromised data may be recovered using a signal processing system. Another embodiment provides for detection of a thermal signal component in a readback signal. The thermal signal is processed for surface information indicative of the surface condition. Information indicating a defect may then be used to avoid storage areas having the defects.

Abstract: Embodiments of systems, methods and article of manufacture provide for readback signal detection and analysis. One embodiment provides an in-situ system to detect envelope traces of a readback signal. Using the envelope data, the presence of undesirable activity and/or storage medium surface conditions may be determined. For example, head modulation may be determined. Upon detection of a modulation event in a sector or a track, the compromised data may be recovered using a signal processing system. Another embodiment provides for detection of a thermal signal component in a readback signal. The thermal signal is processed for surface information indicative of the surface condition. Information indicating a defect may then be used to avoid storage areas having the defects.

Abstract: A method and apparatus for running an analog portion (162) of a read/write channel (108) from a highly regulated power supply (260). The apparatus includes an analog portion (162), a clock synthesizer (154), and a highly regulated power supply (260) connected to the analog portion (162) and the clock synthesizer (154). The analog portion (162) and the clock synthesizer (154) both comprise high voltage transistors which operate in a first voltage range and low voltage transistors which operate in a second voltage range, wherein the first voltage range is within the second voltage range. The highly regulated power supply (260) supplies power that is within the first voltage range to the analog portion (162) and the clock synthesizer (154). The method includes generating power that is within the first voltage range using the highly regulated power supply (260), and supplying the power to the analog portion (162) and the clock synthesizer (154).

Abstract: A system for modeling air bearing designs for heads of a data storage system The modeling system includes user definable surface contours for mask surfaces. The system generates integrated surface functions for the mask surfaces based upon the user defined mask surface contours. The system includes a user definable depth dimension for the mask surface functions and the integrated mask surface functions and dimension parameter for the mask surfaces are compiled to simulate a modeled air bearing structure for performance analysis and evaluation. The integrated mask surface functions are used to define the multiple mask tiers for slider fabrication.

Abstract: The invention relates to a digital-signal processing apparatus for playing back a digital signal recorded on a recording medium, wherein the digital signal is recorded onto the recording medium by delimiting the digital signal at predetermined time intervals into blocks and then processing each of the blocks to convert the digital signal into at least first coefficient data prescribing the amplitude of the digital signal or first coefficient data prescribing the amplitude of a component obtained as a result of conversion of the digital signal and second coefficient data for prescribing the waveform of the digital signal in conjunction with the first coefficient data, and the digital-signal processing apparatus selectively updates the first coefficient data of the digital signal recorded on the recording medium.

Abstract: A matrix array of recording heads, wherein each head is independent from another both in terms of its magnetic circuit and excitation conductors. Each individual head has a planar magnetic circuit and an helical coil wrapped around the lower part of the magnetic circuit. The matrix array is collectively fabricated using full thin film technology on non-magnetic substrates. Preferably, the heads are aligned in an oblique lattice with the write gaps aligned along rows and offset by a constant value along columns. Each individual head is connected to the control electronics through interconnects to the backside of the wafer, allowing independent control of the write parameters. The die forming the device is shaped on its edges and top surface to optimize head/medium positioning and minimize wear.

Abstract: A magnetic transfer method, wherein the master carrier for magnetic transfer having a magnetic layer with a magnetic recording information recorded thereon is closely fitted to the slave medium where the information is to be transferred, and a magnetic recording information of the master carrier for magnetic transfer is transferred to the slave medium, whereby magnetization of the slave medium is performed by initial DC magnetization in track direction, and then, the master carrier for magnetic transfer is closely fitted to the slave medium processed by initial DC magnetization, a magnetic field for transfer is applied in a direction opposite to the direction of the initial DC magnetization on the surface of the slave medium, and magnetic transfer is performed, whereby relation between anisotropy field (Hk) of a master carrier for magnetic transfer and coercive force (Hc) of a slave medium satisfies the following condition: 4×10−4<(Hk/Hc)<2×10−1.

Abstract: An RW offset setting method which includes recording a test pattern by a write head, reading the test pattern by a read head, measuring an amplitude of a read back signal at each tracking position, finding an approximate expression of a profile of the measured amplitude, finding a tracking position, and finding a RW offset based on this tracking position, setting a RW offset for all tracks in the disk device based on the RW offsets about the plurality of tracks to be measured. A read data error recovery method that includes the steps of determining an off-track direction where the amplitude increases, searching an off-track position where the amplitude becomes a local maximum, measuring the amplitude at each off-track position reading data recorded in the data sector.

Abstract: A host-transparent, performance-unaffecting, self-contained write authentication test (SWAT) is implemented in a disc drive to utilize periods of disc drive inactivity to self-verify data written to a disc in a disc drive and further record in the Self Monitoring Analysis & Reporting Technology (SMART) feature of the disc drive, various resultant metrics characterizing the operation of the disc drive during the data authentication. The disc drive maintains a list of recently received write commands, and after a period of inactivity from the host, optionally sorts and parses the list of recent write commands, executes reads from the disc of the data recently written, and records operational parameters characterizing failed data verification during the reads in the SMART feature.

Abstract: A disk drive system including a write circuit for controlling current through a magnetic write head includes an H-switch circuit and a charge-pumping circuit. The H-switch circuit controls direction of current through the magnetic write head. The charge-pumping circuit is connected to the H-switch circuit for storing energy during a first state of the H-switch circuit, and delivering energy upon switching from the first state to a second state of the H-switch circuit to accelerate a change in direction of current through the write head.

Abstract: A method of detecting that a concentration of a low-density gas such as helium in a disc drive is in danger of reaching an unacceptable level includes monitoring a signal varying in response to variations in the concentration of the gas in the disc drive. A criterion is determined based on the signal where the criterion indicates that the gas level is about to reach the unacceptable level. Finally, a flag is set once the criterion is met. A disc drive containing a low-density gas such as helium includes a sensor within the drive that produces a signal responsive to variations in the concentration of the low-density gas in the disc drive. The disc drive also includes a processor that monitors the signal and sets a flag if a predetermined criterion is met.

Abstract: A sampled amplitude read channel incorporated within a magnetic disk storage system for reading data recorded tracks on a magnetic medium, where the data comprises user data sectors recorded at varying data rates across a plurality of predefined zones and embedded servo data sectors recorded at the same data rate across the zones. The read channel comprises a timing recovery component for synchronous sampling of a read signal from a magnetic read head positioned over the magnetic medium, a gain control component for adjusting the amplitude of the read signal, and a DC offset component for canceling a DC offset in the read signal. These components are dynamically configured to operate according to whether the read channel is processing user data or embedded servo data.

Abstract: A system (100) has a storage medium (110) that contains a number of storage units (108). A multimedia title is stored in the storage medium (110) as a number of blocks, whereby some of the blocks are stored multiple times such that different storage units (108) contain a copy of that block. Retrieving blocks from the storage medium (110) for supply to a user is executed in cycles and the system has for some of the blocks the freedom to choose from which of the storage units (108) the block is retrieved in order to balance the load on the storage units (108). Furthermore, the system (100) is arranged to look ahead a number of cycles to determine what blocks in the near future are necessary and to retrieve these future blocks earlier if the storage units are not yet fully occupied. The additional freedom to schedule retrieval of a block at earlier moments in time provides a further mechanism to balance the load on the storage units.

Abstract: The present invention uses temperature readings obtained aperiodically, on demand. Rather than merely obtaining temperature readings on each expiration of a fixed timer, operating parameters are updated in response to a fault detected in the data path. Data handling systems of the present invention each include at least one data path having a thermal range within which it operates best. Applicant notes that some “key” operating parameters typically have a substantial effect on this thermal range. Temperature sensors positioned near the transducers provide a temperature reading to control circuits, which update “key” operating parameter values in response to indications of faults in a primary data path. This reduces the need for more frequent temperature monitoring and calculation-intensive recalibration.

Abstract: A dual channel readback recovery circuit includes a high resolution channel and a low resolution channel and a data latch. A logical filter in one or both channels rejects signals that are followed by other signals if they are spaced apart less than the rejection time interval allowed by the code used. Polarity qualifying logic rejects signals in the channels that are not matched in polarity.