Patent application number | Description | Published |
20080291564 | Detecting head-disk contact during off-track operations - A disk drive that can detect contact between a head and a disk during an off-track operation such as a seek routine, a ramp load or a head take-off. The disk drive includes a circuit that causes the head to move across the disk in a seek routine. A head heater element is driven to move the head into contact with the disk. A read signal provided by the head is filtered through a band pass filter that has a center frequency. The frequency that produces the maximum signal is selected as the center frequency for the band pass filter. The drive can monitor subsequent head contact during an off-track operation by detecting output from the band pass filter. | 11-27-2008 |
20080316635 | Deriving servo PES from DC erased bursts in perpendicular recording - A hard disk drive with a disk that has DC erased servo bursts. The DC erased servo bursts are read by a perpendicular recording head that produces a relatively square burst signal. The burst signal is used determine a position error signal and center the head on a track of the disk. | 12-25-2008 |
20080316639 | Large data block written on overlapping tracks in a hard disk drive - A hard disk drive with a disk that includes a first group of tracks and a second group of tracks. The second group of tracks are used to write large blocks of data. For example, data in the second group may be video or audio. The second group of tracks has a higher track density than the first group of tracks. The large data block is written sequentially in the second group of tracks so that there is only one adjacent track write within the group. Using only one adjacent track write allows the tracks within the second group to be overlapped to increase track density. | 12-25-2008 |
20090067091 | Process for filling a patterned media of a hard disk with UV-cured lubricant - A patterned disk for a hard disk drive. The patterned disk includes a magnetic material over a substrate. The magnetic material includes a plurality of grooves. The grooves are filled with a lubricant that is hardened with UV exposure or some other hardening process. The lubricant provides a protective cover for the magnetic material exposed by the grooves. The use of lubricants in the fabrication of disks is known, thus the process does not introduce a process step that requires special equipment and/or process development. | 03-12-2009 |
20090135693 | Data recovery through eliminating adjacent track interference - A hard disk drive with a disk that contains a target track and an adjacent track. The drive includes a circuit that determines an error in data read from the target track. Data from the adjacent track is stored in memory. The adjacent track is then erased and the target track data is re-read from the target track. Erasing the adjacent track allows the target track data to be read without adjacent track interference. The data from the adjacent track is typically rewritten onto the disk from memory so no data is lost. | 05-28-2009 |
20090147390 | Detecting head/disk contact using timing jitter - A disk drive that includes a head and a disk. The disk drive also includes a circuit that can detect head/disk contact from a jitter determined from a read signal provided by the head. The jitter may correspond to the time interval between two detected sync marks. Alternatively, the jitter may correspond to a change in frequency of a read clock generated from the read signal. These approaches allow for detection of head movement in a down track direction. Down track is a direction that is essentially parallel with the longitudinal axis of the head. | 06-11-2009 |
20090251817 | Data error recovery using voting on multiple retrials - A hard disk drive with a disk that has a plurality of data bits. The drive includes a circuit that reads each data bit n times and selects a value for the bit based on the most frequent occurrence of one of a plurality of values. This process provides a voting technique that enhances the quality of accurately captured data. | 10-08-2009 |
20090273856 | Timing insensitive method and apparatus for spectral analysis in a disk recording system - A hard disk drive that includes a disk that contains at least one signal and a head that is coupled to the disk. The disk drive also contains a circuit that includes a data sampler that-generates a plurality of data samples from the signal, a harmonic sensor coupled to the data sampler and a spectral power accumulator coupled to the harmonic sensor. The harmonic sensor accumulates the data samples. The circuit includes a window generator that determines a window length of the data samples accumulated by the harmonic sensor. The spectral power accumulator accumulates the windows of sample data accumulated by the harmonic sensor. The sample data accumulated by the spectral power accumulator can be accessed by a processor that performs a spectral analysis of the data. | 11-05-2009 |
20100128380 | SES ASSISTED WRITE FLY HEIGHT MONITOR AND CONTROL - A hard disk drive that includes a disk, and a head that is separated from the disk by a flying height. The disk drive also includes a circuit that determines the flying height from a signal read during a write operation of the drive. The circuit performs a calibration routine to determine a temperature dependent variable of the signal to offset any temperature effects on the signal used to determine the flying height. The calibration routine can be performed using a spacing error signal (“SES”) generated by the drive. | 05-27-2010 |
20100128399 | HARMONIC MEASUREMENT FOR HEAD-DISK SPACING CONTROL USING USER DATA - A hard disk drive that determines a flying height from a ratio of a first harmonic transfer function and a third harmonic transfer function. The transfer functions can be determined from a response to an impulse function. The impulse function (also known as an impulse response) can be a playback waveform de-convolved by channel data sequence. Any change in the ratio of the first and third harmonic transfer functions corresponds to a change in the flying height. The disk drive may utilize the transfer function ratios in a feedback routine to control the flying height. | 05-27-2010 |
20100149677 | SELF-SPINNING DISK BULK ERASURE FOR HARD DISK ASSEMBLY - A method for erasing a disk of a hard disk drive. The method includes moving the hard disk drive adjacent to an erasure head that emanates a magnetic field. The magnetic field and moving hard disk drive cause a disk of the hard disk drive to spin under a Lorentz force created by the magnetic field and moving disk. The magnetic field is applied by the erasure head for a duration that causes erasure of the entire disk. The spindle motor is not activated during the entire process. Not activating the spindle motor eliminates any Faraday coupling from the erasure head into the motor. | 06-17-2010 |
20100177418 | WRITER AND READER CENTER ALIGNMENT WITH SERVO AND DATA TRACK IN DISCRETE TRACK RECORDING - A hard disk drive with a patterned disk that has a discrete track. The disk drive includes a controller that controls a head and a voice coil motor to optimize a writing of information onto the discrete track. Writing optimization can occur by initially writing a track of information and recording the write position. The written track is then located by reading the information with a read element of a drive head and analyzing a quality of the read signal, such as signal amplitude or error rate. The read position is then recorded. The information is erased and the head is moved. The process of writing, finding the written track location, storing the write and read positions and again moving the head is repeated. The write and read positions that provide the best quality signal is saved and subsequently used to write and read data on the discrete track. | 07-15-2010 |