Abstract: A head suspension has a segmented trace conductor array for electrically interconnecting a read/write head to electronic circuitry in a disk drive. Each trace segment has a predetermined generally rectangular cross-sectional area such that the intermediate first segment has a predetermined cross-sectional width greater than a predetermined cross-sectional width of an first outer segment, in order to optimize current density at very high signaling frequencies associated with information transfer between the head and the read/write circuitry.

Abstract: According to the invention, a data integrity code including logical block address ("LBA") and circuit implementation are provided. The code and implementing circuitry are utilized to enable data block LBA verification during a block transfer and retrieval process. The preferred data integrity code has embedded LBA information and also serves as a crosscheck code used to detect miscorrection by an error correction code ("ECC"). In a preferred disk drive embodiment, data integrity block ("DIB") is provided to verify that the LBA value associated with a given data block in a host interface matches the value associated with that same data block in a buffer memory and in a data sequencer. In a preferred method of use, data integrity/cross-check redundancy with LBA is appended to data blocks transmitted to a buffer memory and verified after the data block has been transferred from the buffer.

Abstract: The pole pieces of a thin film head are formed by two thin film layers of the magnetic metal NiFe, each NiFe layer being about 20,000 angstroms thick. These two NiFe layers are separated by an electrically insulating layer of alumina (Al.sub.2 O.sub.3), ceramic or NiFe oxide that is about 100 angstroms thick. In one embodiment, a hard-baked photoresist layer is formed only around the edges of the first NiFe layer, the electrically insulating layer is deposited over the top surface of the first NiFe layer and over the hard-baked photoresist layer, and the second NiFe layer is then deposited, thus providing a three-layer metal/insulator/metal pole piece wherein the hard baked photoresist blocks edge short circuiting between the two thin film NiFe layers.

Abstract: A head suspension has an integrated multi-layer trace conductor array for supporting and electrically interconnecting a read/write head to electronic circuitry in a disk drive. The trace conductor array includes an integrally formed electrical shield which may be grounded or ungrounded and formed to have a depth greater than a skin effect depth at a frequency of an interfering wave front.

Abstract: In a disk drive using a write-wide inductive write element and a read-narrow magneto-resistive read element within a head transducer assembly for writing and reading magnetic patterns on a rotating magnetic storage disk in a plurality of concentric tracks, a track pattern formed in each concentric track includes embedded servo wedges wherein each wedge includes a servo position portion which is offset from a centerline of both the servo sector and a following user data sector by an amount related to offset between the inductive write and magneto-resistive elements of the head transducer assembly. Furthermore, the servo sector contains four servo bursts. The servo bursts are arranged such that each sequential burst is offset from a previous burst by a fractional offset increment. The fractional offset increment is typically one-third of a track pitch.

Abstract: Embedded servo sectors within a data track of a hard disk drive including a rotating data storage disk and a closed loop rotary actuator structure for positioning a data transducer head relative to the data track are written by a method including the steps of positioning the rotary actuator structure relative to the data track with a laser-interferometer-based servo writer and writing a pattern of circumferentially sequential, radially offset fine position bursts within each servo sector with the data transducer head, this step including writing-in undetermined position errors within each pattern being written, moving the disk drive to a self scan environment away from the servo writer, operating the rotary actuator structure in closed loop for following the data track by reference to the servo burst pattern, extracting the undetermined position error from each pattern thereby to iteratively determine written-in position errors, generating burst correction values from the determined written-in position errors

Abstract: A magnetic tape head actuator assembly has a stepper motor having a threaded output shaft and a bracket for supporting a tape head assembly. The bracket includes a pair of outwardly extending flanges. The flanges each have a bore, whereby the bores are axially aligned and dimensioned to accept the output shaft therethrough. The bracket further has an integral platform portion oriented normal to the threaded output shaft for mounting a tape head assembly. A threaded split nut positioned intermediate the bores is rigidly attached to the bracket and engages the threaded output shaft for movement of the bracket back and forth along the shaft. The nut further has an annular groove encircling its outer perimeter, wherein a circular spring positioned therein provides an inwardly directed compressive force on the nut.

Abstract: A single reel tape cartridge includes a type of magnetic recording tape having characteristics which are identified to a cartridge tape handling system in accordance with size variation of a tape type hole following a beginning of tape (BOT) hole by a predetermined, qualifying distance. A cartridge tape handling system for identifying the particular tape type, and for formatting the tape in accordance with determined tape type is also described.

Abstract: A method of performing spectral analysis of signals recorded by a magnetic recording or storage system is provided using a modified channel chip of the system. The modified channel chip enables measurement of harmonic components of the recorded signal. The recorded signal is a periodic analog signal having a period N. The method is performed by reading the recorded periodic analog signal and converting the signal into a discrete time periodic signal. The discrete time periodic signal is digitally sampled at predetermined intervals, and the digital samples are selectively accumulated in a register or registers of the channel chip. Incoming digital samples are accumulated by selectively being added to contents of the registers, or alternately being added and substracted to contents of a single register. The accumulated results represent summations used to determine harmonic coefficients of the recorded signal.

Abstract: A multiple-solid-burst error correcting system determines the number and locations of "solid burst" errors in a high-rate Reed Solomon or BCH code by determining the greatest common divisor of the error locator polynomial .sigma.(x), which has roots .alpha..sup.-i.sbsp.k that correspond to error locations i.sub.k, and a mapping error locator polynomial .sigma.(.alpha.*x) that maps the error locations , i.sub.k, to locations i.sub.k+1. The roots that are common to both polynomials, that is, the roots that are included in the greatest common divisor, d(x), correspond to adjacent error locations that are contained in the solid bursts. The roots of the non-common factors, p.sub.1 (x), of the error locator polynomial correspond to the first locations of the respective solid bursts and the roots of the non-common factors p.sub.2 (x) of the mapping error locator polynomial correspond to one location beyond the end locations of the solid bursts.

Abstract: A Reed-Solomon error-correction coding (ECC) scheme selectively supports two different-length codes to optimize the trade-off between error performance and the amount of disk space required to store protection symbols. The encoder contains two sets of alpha multipliers; part of one set is multiplexed with the other depending on which code is being used. Also, a shift register within the encoder is selectively lengthened or shortened depending on the code. The code pair is selected so that the generator polynomial of the shorter code is a complete divisor of the generator polynomial of the longer code. Thus, one code is a sub-code of the other. Accordingly, the ECC system is able to use the same syndrome calculator for each code. The error-correction decoder uses those syndromes that correspond to the roots of the generator polynomial of the code being used.

Abstract: A pulse width modulated, digital-to-analog converter (PWM DAC) that includes a pulse generator for generating width modulated pulses in accordance with a digital control value is set forth. The generator includes a clock for generating a clocking signal, a counter responsive to the clocking signal for generating repeating sequences of N-bit counts, each sequence representing a count interval. The PWM DAC further includes a bit rotator for receiving the sequences of N-bit counts and for rotating the bit position of at least a most significant one of N-bits. A latch holds a digital control value, whereby a comparator compares the digital control value with each one of the rotated bit counts to put out the width modulated pulses during the count interval. The rotated bit counts increases the frequency of the comparator, in a substantially linear manner, such that subsequent filtering can be accomplished with minimum time requirements.

Abstract: Rate 24/25 modulation encoding methods and apparatus improve efficiency in a PRML magnetic recording channel. The rate 24/25 code word uses rate 8/9 RLL encoding of one byte of user data, combined with interleaved unencoded bytes to achieve improved code rates with reasonable global run length constraint. Use of the the rate 8/9 RLL (0,3) subcode results in a rate 24/25 RLL (0,11) code, while a rate 8/9 (0,6/5) subcode results in a rate 24/25 RLL (0,14/13) code.

Abstract: A word-wise encoder circuit that processes word formatted data blocks in response to a word clock signal and generates redundancy in accordance with an 8 bit symbol code. The encoder is provided with two parallel data paths, each receiving one of the respective bytes halves of the received data words during one word clock period to implement an 8 bit symbol code in response to a word clock signal. The word-wise encoder replicates, in one word clock period, the state of the registers in a standard sequential encoder after two consecutive bytes have been processed in response to a byte clock. In a preferred embodiment, a word-wise encoder is used to implement a Reed-Solomon data integrity code. In this example, the word-wise encoder generates redundancy that is appended to associated data blocks temporarily stored in a block buffer memory within a data channel to provide a mechanism for detecting data errors caused by the buffer.

Abstract: A head suspension has an integrated self-shielding trace conductor array for supporting and electrically interconnecting a dual element read/write head to electronic circuitry in a disk drive. Write traces are placed proximately to the read traces and are grounded during data reading operations in order to serve as a read trace electrostatic shield during the data reading operations.

Abstract: A method and apparatus for processing a magnetic transducer which uses gallium ion beam milling to precisely define pole tip widths of the magnetic transducer. The gallium ion beam may be defocused to improve definition of the region which is damaged by gallium ion implantation. The precision pole tip widths provide a transducer that may record correspondingly precise track widths on a magnetic storage medium, such as a rotating disk. Subsequent to the ion milling process, the invention restores the magnetically conductive properties of the pole tip region, which may be degraded as a result of the ion milling process, by means of a lapping process.

Abstract: A method and apparatus for reconstructing syndromes in a disk drive system. In the present invention, two levels of handling data errors are provided. The first attempt at correcting errors is performed by a dedicated error correction hardware. The error correction is based on a syndrome which was generated as a function of the data and ECC bits. An ECC code is selected such that the resulting syndromes produces a repeating, cyclical pattern. If the hardware correction circuit is unable to correct the error, the original syndrome value is reconstructed by processing the syndrome a number of times to where its current value in the next cycle corresponds to the original value in a previous cycle. This reconstructed syndrome is then used by the processor to handle the persisting error under firmware control.

Abstract: A head suspension has an integrated multi-layer trace conductor array for supporting and electrically interconnecting a read/write head to electronic circuitry in a disk drive. The electrical micro strip transmission line characteristics of the conductor array is controlled by the selective placement and connection of the trace paths within the multiple layers in order to control and balance electrical parameters including array inductance, inter-trace capacitance, and trace capacitance to a ground plane. The ground plane may further comprise a solid sheet of material or an arrangement of grounded traces disposed in proximity to signal-carrying traces of the micro strip transmission line in order to control and obtain desired electrical characteristics.

Abstract: A method for forming a precision groove in a cylindrical surface of an article such as a sleeve-shaft hydrodynamic journal bearing system includes the steps of: aligning a groove-forming machine to an axial datum plane of the article defined in a spaced-apart relation with the cylindrical surface by a predetermined nominal first dimension, translating the groove-forming machine in an axial direction toward and upon a first edge of the cylindrical surface by an amount equal to the predetermined nominal first dimension and thereupon forming a first groove axial step segment in the cylindrical surface until a second predetermined axial datum plane is reached, simultaneously axially translating and rotating the groove-forming machine from the second axial datum plane until a third predetermined axial datum plane is reached and thereupon forming the precision groove pattern in the cylindrical surface between the second axial datum plane and the third axial datum plane, and axially translating the groove-forming ma

Abstract: A pressure differential actuator latching apparatus for a disk drive device is provided. The latching apparatus includes a rotatable body portion, a rigid air vane portion and a latching trap. When a data storage disk of the disk drive is not being rotated, the latching apparatus maintains a transducer actuator assembly of the disk drive in a locked position by engaging the transducer actuator assembly in the latching trap. When the data storage disk is rotated, airflow is generated proximate to the surface of the disk, in the same direction in which the disk is rotated. The transducer actuator assembly, positioned over the surface of the disk, blocks the airflow. The blockage of airflow creates an area of low pressure just downstream of the actuator assembly. The latching apparatus is disposed in a space between the edge of the data storage disk and walls of the housing so that the air vane portion is positioned between the areas of low and ambient pressure.