Did You Know...
...that in 1800 ether was first used by partyers as a fun diversion? Sniffing the gas led to hilarious and raucous laughter as people watched each other become more and more intoxicated and silly. Several doctors independently realized the value ether would have to anesthetize surgery patients. Of those who claimed rights to the "discovery," none had a happy ending. One had a seizure and died defending his rights. Another spent his life in an asylum because he had been denied acclaim. A third became addicted to chloroform and, in a New York City jail, he soaked a cloth in the drug, severed an artery and bled to death.
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| Number | Title | Issue Date |
| 6751042 | Track pitch correction method and apparatus Many parallel tracks on a storage surface of a data handling device are arranged in a longitudinal direction. Each track has a track center comprising reference points for fine lateral positioning. Each successive pair of track centers has a succession of lateral of... | 06/15/2004 |
| 6747837 | Disk drive comprising an integrator for controlling a VCM actuator and transformer for controlling a piezoelectric actuator A disk drive is disclosed comprising a voice coil motor (VCM) actuator and a piezoelectric (PZT) actuator. The VCM actuator is driven by a control effort including an integrator, and the PZT actuator is driven by a control effort including a transformer. ... | 06/08/2004 |
| 6747833 | Magnetic disk drive with a head oscillation function and the control method thereof The position information of the magnetic head is generated also from the data area to improve the positioning accuracy. The magnetic disk drive has a function of oscillating the magnetic head in the radial direction in the data area at a specific frequency and a fun... | 06/08/2004 |
| 6747836 | Position control system and method for magnetic hard disk drive systems with dual stage actuation A head position control system for a dual stage actuation disk drive system. A feedback system is provided for modifying a primary and a secondary input command signal to produce primary and secondary error signals. A controller receives the primary error signal and... | 06/08/2004 |
| 6744589 | Single-sided unipolar device driver for a piezoelectric transducer in a disc drive A disc drive including a rotatable data track, a dual-stage actuator with a primary actuator motor supporting an actuator arm, a read/write head supported by the actuator arm and communicating with a secondary actuator motor, and steps for controlling range of motio... | 06/01/2004 |
| 6738218 | Disk storage device and head positioning method Settling response characteristics after change-over from a speed controller to a position controller is attained. Fluctuations in a time taken until change-over is made from the speed controller to the position controller are reduced to stabilize a moving time and t... | 05/18/2004 |
| 6735033 | Method for recovering from shock events occurring to a disk drive during data write operations to improve data reliability The invention relates to a method for recovering from shock event to a disk drive. Embedded servo wedges are read to generate position error signal (PES) values. The disk drive is transitioned to a write unsafe state if a PES value is greater than a write unsafe (WU... | 05/11/2004 |
| 6724561 | Apparatus and method for compensating for environmental effects on media An apparatus and method for compensating for environmental effects on media. The apparatus includes an array of servo readers that are positioned at a non-zero azimuth angle relative to a medium. The position of the array of servo readers is dynamically updateable i... | 04/20/2004 |
| 6724563 | Two-stage actuator with sensitivity function preventing disturbances at all frequencies By increasing the gain of a controller for coarse motion CFBV within a frequency band in which the gain of a sensitivity function SP=1/(1+PP·CFBP) of fine motion actuator DP and controller for fine motion CFBP exceeds 0 dB, the gain of a sensitivity function SV=1/(... | 04/20/2004 |
| 6724560 | Head assembly employing microactuator in recording medium drive A head suspension supporting a head at the tip end is allowed to swing at the tip end of a carriage in a recording disk drive. A microactuator is interposed between the head suspension and the carriage. A resistor is connected to the microactuator in serial. The mic... | 04/20/2004 |
| 6721121 | In-situ determination of landing zone transition for improved disk drive reliability A data storage disk is formatted using a measured edge location of a textured landing zone as a reference for writing servo information to the surface of the disk. The edge of the textured landing zone is determined by moving a transducer across the surface of the d... | 04/13/2004 |
| 6721122 | Disk drive unit and control method for same A disk drive unit includes acceleration sensors mounted thereon. A sequence for calculating an amount by which a head actuator is adjusted during recording and readout operations is changed based on an output from the acceleration sensors. ... | 04/13/2004 |
| 6717761 | Recording/reproducing apparatus A recording/reproducing apparatus capable of switching over among a plurality of heads with high precision, wherein the apparatus is provided with: a recording/reproducing unit for recording/reproducing signals onto/from a recording medium with a plurality of heads;... | 04/06/2004 |
| 6710966 | Method for reducing an effect of vibration on a disk drive during a track following operation by adjusting an adaptive-filter gain applied to an acceleration sensor signal The present invention may be embodied in a method, implemented in a disk drive, for adaptively reducing an effect of vibration during a track following operation. The disk drive includes a disk and a rotary actuator. The disk includes distributed position informatio... | 03/23/2004 |
| 6710965 | Phase-advanced filter for robust resonance cancellation A filter for attenuating a resonance mode without substantial phase margin loss. The filter comprises a transfer function having an additional pole, such that the phase of the input signal is advanced. The phase-advanced filter substantially attenuates all frequenci... | 03/23/2004 |
| 6707633 | Magnetic disk device including coarse and micro actuators A magnetic disk device comprises at least a disk having information, at least a head for reading or writing information from or into the disk, at least a micro actuator for supporting the head and positioning the head, a coarse actuator for carrying the micro actuat... | 03/16/2004 |
| 6707635 | Method and apparatus for RRO learning on alternate tracks before and after shipping to cancel RRO in a disk drive The present invention may be embodied in a method, and related apparatus, for determining a repeatable runout (RRO) compensation value sets for a plurality of tracks on a disk in a disk drive, wherein the disk drive is initially manufactured and then shipped for ins... | 03/16/2004 |
| 6690534 | Method and apparatus for handling multiple resonance frequencies in disc drives using active damping A method of handling multiple resonance frequencies in a disc drive includes monitoring a position error signal (PES) for an actuator arm, generating a plurality of feedforward compensation signals from the PES using a plurality of bandpass filters, and a... | 02/10/2004 |
| 6690537 | Method and system for controlling the positioning of a read/write head of a data recording device A read/write head servo control system for data recording devices, wherein a method of compensating initial values is utilized to generate a control signal to move the head from an initial position to a target position. The method estimates and stores mul... | 02/10/2004 |
| 6683737 | Method and apparatus for predictive failure analysis technique for head crashes in hard drives using position error signal A position error signal indicative of the distance between an expected position of a magnetic head relative to the track centerline of a magnetic data storage and retrieval system and an actual position of the magnetic head relative to the track centerlin... | 01/27/2004 |
| 6671790 | Optimizing reader to writer offset compensation for a disc drive A method for optimizing logical track to physical track offset compensation of a data storage device includes steps of: associating each of a plurality of logical tracks to one of a plurality of physical tracks, selecting a set of sample tracks from the p... | 12/30/2003 |
| 6667840 | Method for screening oscillatory PES with 1.7 kHz harmonic resonance The present invention provides a method to screen tracks on a magnetic disc in a disc drive for harmonic resonance. There are several algorithms in the method performing different functions at various stages of the method. At any point in time, only one t... | 12/23/2003 |
| 6665138 | Technique for detecting head position in hard disk drive A technique for detecting a current position of a head of a hard disk drive detects the position of the head by using an analog-to-digital conversion value of a single crossing point of one of first and second servo burst signals written up and down with ... | 12/16/2003 |
| 6661359 | Device and method for generating synchronous numeric signals A device for generating synchronous numeric signals, including a reference generating device supplying a reference signal and a first timing signal, both having a reference frequency; and a timed generating device supplying a synchronized signal having th... | 12/09/2003 |
| 6657805 | Method of controlling read write operation of a magnetic disk apparatus When the amount of position error PE of a magnetic head meets the condition of Ewf>PE>=Eww for two threshold values Ewf and Eww meeting Ewf>Eww, the track is registered in the track information table as a track requiring rewrite and the tracks on both sid... | 12/02/2003 |
| 6657801 | Disk drive with improved characterization segment pattern and method of recording the same A disk drive and related method, the disk drive including a rotating magnetic disk and read and write elements for reading and writing data from and to the rotating magnetic disk, comprising: a magnetic characterization pattern recorded on the rotating ma... | 12/02/2003 |
| 6654195 | Disk drive having a register set for providing real time position variables to a host A disk drive provides head position information as position status variables to a host. The position status variables are derived from information formatted on a disk and processed by a media controller for storage in a position register set. The position... | 11/25/2003 |
| 6650491 | System and method for setting a read/write offset and for recovering from data read errors 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 mea... | 11/18/2003 |
| 6646824 | Head-positioning control method and device for a disk device This invention relates to a head-positioning method and device for positioning the head, that reads a disk medium, to a specified position. A disk device having a head, actuator and control circuit comprises: a demodulation unit for demodulating the demod... | 11/11/2003 |
| 6646823 | Disk drive using offset data sectors A disk drive stores data within a single track of a data storage disk at two different lateral positions with respect to the track centerline. The radial distance between the two lateral positions is preferably equal to the lateral offset between the read... | 11/11/2003 |
| 6643084 | Adaptive off-track recovery A method and system for adaptively limiting an off-track recovery displacement of a recording head during an off-track data recovery operation. A head disk assembly (HDA) includes an actuator that positions the recording head in accordance with an actuato... | 11/04/2003 |
| 6636376 | Disc drive resonance disturbance cancellation filter An apparatus and method for canceling nonrepeatable runout position error in a disc drive. Pursuant to the method, a frequency of a specified nonrepeatable runout disturbance is determined. A position error signal indicative of a position of a read/write ... | 10/21/2003 |
| 6636375 | Seek in a disc drive with nonlinear pivot friction According to one embodiment of the present invention, a disc drive includes a disc and a transducer supported by an actuator assembly that is accelerated by controlling current in a voice coil. The disc drive controls a position of the transducer over a p... | 10/21/2003 |
| 6628471 | Detection and cancellation of cage frequency using the clock head in a servowriter The magnitude and frequency of runout due to vibration of the cage of the spindle motor is detected. A plurality of servo patterns are written to a reference track having a clock pattern on the disc, and the plurality of servo patterns are then read over ... | 09/30/2003 |
| 6618220 | Head actuator and hard disc drive including the same A head actuator includes a head slider for carrying a head for recording information to or reproducing information from a recording medium; and a head supporting member for supporting the head slider. The head supporting member includes a substrate and a ... | 09/09/2003 |
| 6614609 | Gray code detection for a disk drive system A disk drive system is disclosed that includes a disk device coupled to control circuitry. The control circuitry includes a read channel with a detector that detects a bit sequence associated with Gray codes and delays indications of the bit sequence dete... | 09/02/2003 |
| 6614614 | Method and apparatus for writing servo pattern The invention relates to a method for writing servo patterns on a data recording disk of a disk drive device. A read/write head is stopped at a reference position on the data recording disk, then the read/write head is moved along a radial direction of th... | 09/02/2003 |
| 6608731 | Dynamic reduction of track shape errors in disc drives The invention eliminates relative and absolute track shape errors by writing zero acceleration path (ZAP) correction factors into the servo sectors during track propagation. A servo track guide zone is written to the disc. ZAP correction factors are writt... | 08/19/2003 |
| 6606213 | Actuator resonance screening in disc drives A disc drive system and method of screening an actuator resonance includes a servo controller providing a multi-servo zone architecture. The servo controller partitions the disc into a plurality of servo zones. Each of the servo zones has a corresponding ... | 08/12/2003 |
| 6606214 | System and method to minimize bearing pivot effect in disc drive actuator A disc drive is provided which incorporates a rotatable actuator which is mounted to a base of the disc drive through a pivot mechanism. The actuator positioning is controlled by a servo system and during track following operations, the actuator arm is ca... | 08/12/2003 |
