Abstract: A self servo writing file and method for writing servo patterns in a direct access storage device are provided. First servo information is written on a data storage media at a first crash stop. The transducer heads are moved offset from the written servo information while reading the last written servo information until the detected servo signal equals a predetermined value. Then servo information is written on the data storage media responsive to the detected servo signal equal to the predetermined value. The moving and writing steps are sequentially repeating until a second crash stop is reached. A quad-burst servo amplitude pattern or phase pattern can be used for the servo information. The servo writing method is adapted easily for many different servo options. When the file uses a hybrid servo or sector servo, the other surfaces can be written by duplicating the servo bursts with a high bandwidth servo system of the file.

Abstract: Storing data on a data processing system is done upon generation of a data file by displaying a user interface allowing user selection of storage criteria for the data file. Responsive to user selection of storage criteria for a file determining a physical format type for the file from a plurality of available physical format types. Then the file is stored on a direct access storage device as at least a first record conforming with the determined physical format type.

Abstract: A method and apparatus are provided for writing servo bursts with compensation for erase bands in a direct access storage device (DASD). A first servo burst is written on the magnetic disk media using a transducer head in the DASD. The transducer head is moved in a first direction and the first written servo burst is trimmed. The transducer head is moved in a second direction opposite the first direction corresponding to the width of an erase band and then a next servo burst is written.

Abstract: A self servo writing file and method for writing servo patterns in a direct access storage device are provided. First servo information is written on a data storage media at a first crash stop. The transducer heads are moved offset from the written servo information while reading the last written servo information until the detected servo signal equals a predetermined value. Then servo information is written on the data storage media responsive to the detected servo signal equal to the predetermined value. The moving and writing steps are sequentially repeated until a second crash stop is reached. A quad-burst servo amplitude pattern or phase pattern can be used for the servo information. The servo writing method is adapted easily for many different servo options. When the file uses a hybrid servo or sector servo, the other surfaces can be written by duplicating the servo bursts with a high bandwidth servo system of the file.

Abstract: A method and apparatus is provided which introduces a relative skew between a servo pattern and a magneto-resistive (MR) head in order to reduce interference introduced by inductive reading of shields formed as part of the MR head. The relative skew may be accomplished by introducing a skew angle directly on the head or by skewing the servo pattern formed on the magnetic medium relative to the head. Various skewed patterns may be used to reduce the overall interference.

Abstract: A disk drive stores multimedia data in long spiral data tracks. The tracks on opposite surfaces of the disk spiral in opposite directions, so that a track on one surface can be read as the actuator sweeps in, and a track on the opposite surface can be read as the actuator sweeps out. Because the actuator only follows spiral tracks without performing long seek operations, the actuator motor can be reduced in size and stresses on actuator bearings and other parts are reduced. Additionally, due to reduced disturbances associated with seeks, it is possible to follow tracks more closely and therefore reduce the width of individual tracks. Further cost reductions are accomplished by spinning the disks at a slower speed and reducing the size of the spin motor accordingly. Finally, data density can be increased simply because multimedia data does not require the same low error rate as conventional data. Preferably, a group of disk drives optimized for multimedia data is used to form a video-on-demand system.

Abstract: The magnetic states of MR reproducing heads are reinitialized during media drive manufacturing by applying initializing magnetic fields to the transducers after they have been manufactured and incorporated into media drive assemblies.

Abstract: A self servo writing file and method for writing servo patterns in a direct access storage device are provided. First servo information is written on a data storage media at a first crash stop. The transducer heads are moved offset from the written servo information while reading the last written servo information until the detected servo signal equals a predetermined value. Then servo information is written on the data storage media responsive to the detected servo signal equal to the predetermined value. The moving and writing steps are sequentially repeated until a second crash stop is reached. A quad-burst servo amplitude pattern or phase pattern can be used for the servo information. The servo writing method is adapted easily for many different servo options. When the file uses a hybrid servo or sector servo, the other surfaces can be written by duplicating the servo bursts with a high bandwidth servo system of the file.

Abstract: A peak detector for extracting pulses in a magnetoresistive sensor circuit while suppressing the recovery transients created by thermal asperities. The disclosed peak detector circuit is a simplified variation of the standard magnetoresistive sensor peak detector circuit. The signal differentiation is performed ahead of the usual amplification to remove transient pulse amplitudes before they can affect the AGC gain. The resulting differentiated signal is processed by a modified amplitude qualification circuit to extract data output pulses. The thermal asperity transient recovery period is eliminated without additional circuit complexity, leaving only the initial thermal asperity pulse effects to be corrected by any suitable relatively simple error correction code (ECC).

Abstract: A multipath channel apparatus for a data storage device wherein data is stored on a storage medium and is read from the storage medium by a transducer or for a data communications system wherein data is transmitted to a receiver. A data channel having a plurality of data paths is operatively connected to the transducer to receive data read from the storage medium by the transducer, or operatively connected to receive data demodulated by the receiver or base band data received by the receiver. Preferably, each of the data paths has a differing parameter value. An error checking unit checks customer and redundancy data from each of the data paths. A selecting unit, which is responsive to the error checking unit, selects data from one of the data paths. In a preferred embodiment, the data stored on a storage medium includes a data field and an error correcting code field, and the customer and redundancy data from each of the data paths is checked using a calculated error correcting code sydrome.

Abstract: A peak detector for extracting pulses in a magnetoresistive sensor circuit while suppressing the recovery transients created by thermal asperities. The disclosed peak detector circuit is a simplified variation of the standard magnetoresistive sensor peak detector circuit. The signal differentiation is performed ahead of the usual amplification to remove transient pulse amplitudes before they can affect the AGC gain. The resulting differentiated signal is processed by a modified amplitude qualification circuit to extract data output pulses. The thermal asperity transient recovery period is eliminated without additional circuit complexity, leaving only the initial thermal asperity pulse effects to be corrected by any suitable relatively simple error correction code (ECC).

Abstract: A disk drive slider is designed to make contact, if any, in a region of the slider which does not have a substantial effect on the fly height. Preferably, the slider utilizes a tapered center rail having a narrow tail which is closest to the disk and a pair of outside rails which are wider at the leading edge. The center rail tapers from a narrow leading edge to a wider support region and then tapers to a narrow trailing edge. The trailing edge is closest to the disk and provides virtually no contribution to aerodynamic support of the slider. Since the trailing edge does not contribute to the support of the slider, any contact induced wear can be tolerated without affecting the fly height. Even further, the wear characteristic is self-limiting. That is, after the initial wear has taken place, the likelihood of further wear is reduced.

Abstract: Disclosed is a disk drive having at least one disk for storing data. The disk drive includes at least one transducer for reading or writing data to or from the disk. The transducer is attached to an actuator which positions the transducer with respect to the disk. The actuator includes a controllable motor which is used to move the actuator and the transducer attached thereto. The disk drive also includes a ramp for off loading the transducer or for parking the transducer off of the surface of the disk. Also disclosed is apparatus and methods for measuring and controlling the movement of the actuator and attached transducer while the transducer is coming from a position off of the ramp and onto the surface of the disk.

Abstract: Apparatus and method of data recovery are provided for data detection in a partial-response (PR) data channel. The PR data channel includes an analog-to-digital converter (ADC) for providing digital samples of a readback data signal and a voltage controlled oscillator (VCO) timing control coupled to the ADC. A data recovery procedure (DRP) is established responsive to a detected readback error. Using amplitude offset circuitry, amplitude of the readback data signal is selectively adjusted responsive to the detected readback error; and using gain control, a correction current applied to the VCO timing control is changed responsive to the detected readback error.

Abstract: A method and apparatus is disclosed for adaptively controlling the biasing current applied to magnetoresistive (MR) read heads within a magnetic disk drive to provide optimized bias for each head/disk/channel component combination. An optimized bias current for each head is ascertained and stored on the disk surface at the time of manufacture. During each power up operation the values are transferred to random access memory which is accessed during the execution of each head switch command to apply bias current in accordance with the optimized value to the active MR head. Periodic reoptimization and updating of the stored values is effected by general error measurement circuitry that forms a part of the device control system and is invoked to perform the reoptimization upon the occurrence of an event such as a predetermined duration of power on operation subsequent to the last reoptimization procedure.

Abstract: A method and apparatus are provided for data recovery in a disk drive data storage system of the type including at least one disk surface and at least one transducer head for reading and/or writing data to a respective disk surface. A plurality data recovery procedures (DRPs) are stored. When a readback error is detected in a readback data signal, a plurality of predetermined transducer head and disk parameters are identified. One of the stored plurality of data recovery procedures (DRPs) is selected responsive to the detected readback error and the identified plurality of predetermined transducer head and disk parameters.

Abstract: Disclosed is a slider with an air bearing surface for flying a magnetic transducer on an air lubrication film over a moving recording medium. The air bearing surface allows the slider to fly at a close and substantially uniform height over the disk surface regardless of the skew angle of the air flow. The slider has a pair of nonidentical, nonsymmetrical rails disposed about the longitudinal axis of the slider, which through the viscous effects of the air flow, provide the air lubrication film when the recording medium is in motion.

Abstract: A dedicated servo transducer head for phase skewed position information signals in servo information tracks of a rigid magnetic disk drive unit has a width spanning up to eight servo information tracks in order to overcome problems in gain irregularity caused by abrupt phase jumps between tracks. An embodiment of the invention includes a track reading surface that varies in sensitivity across the width of the head to avoid gain loss during incremental radial movement with head edges overlying track edge fringes.

Abstract: Clocking of Class IV partial response coded binary data is provided by way of circuit means that includes two analog threshold detectors. One detector is responsive to the analog read signal's positive-going amplitude corssing a a preset positive threshold value. The other detector is responsive to the read signal's negative-going amplitude crossing a preset negative value. The time of occurrence of both detector crossing transitions is phase-compared to a clock signal, and a phase error signal is generated for each detector, if a phase error exists. The two phase error signals are integrated by the use of a loop filter. The integrated phase error signal is then used to adjust the phase of a clock signal generator. The output of the clock signal generator is used to accurately clock, and to enable accurate recover of, the binary data that was originally encoded and written in accordance with the Class IV partial responsive coding convention.

Abstract: A magnetic recording apparatus and method for the constant frequency recording of concentric data tracks on a magnetic recording disk in a manner to provide continuously reducing track width and continuously reducing track-to-track spacing from the disk's inner track to the disk's outer track. A magnetic recording head moves on a path from the disk's inner track to the disk's outer track. The head's gap-to-radius skew increases as the head moves from the inner track to the outer track. Thus, the gap's width-projection onto a disk radius at the location of each track continuously decreases in length, from the inner track to the outer track. As the track width progressively decreases, the track-to-track spacing also decreases, to thereby provide higher track density at the disk's outer tracks. A flying head having a parallelogram shaped slider is described, allowing use of the invention in non-contact recording.