Abstract: A hard disk drive that contains a self-test for generating data on head spikes. The data is stored on a system track of the drive. The self-test may be firmware embedded into a memory device of the drive. The self-test automatically runs when power is provided to the drive. This allows for a 100% spike detection test for disk drives assembled at a manufacturing facility. The self-test includes writing a test waveform, reading the test waveform and comparing the read waveform with a threshold to determine the existence of spikes. Data on the spikes is then stored on the system track. The data is compared with certain criteria to determine whether the disk drive is defective.

Abstract: A data sector format suitable for a high density hard disk drive includes an ID region for writing ID information for the data sector, and a data region for writing data transferred from an external device. The ID region is formed within the data region and a synchronization signal for reading the ID information is written into the data region. The data sector includes a data sync region for writing a synchronization signal for reading information written on the data sector, the ID region for writing ID information for the data sector, a PAD region for separating the ID region and the data region, a data address mark region for indicating a validity of data written on the data sector, the data region for writing the data transferred from the external device, and an error correction code region for writing an error correction code to automatically correct an error upon occurrence of a defect when data is written on the data region.

Abstract: A data sector format suitable for a high density hard disk drive includes an ID region for writing ID information for the data sector, and a data region for writing data transferred from an external device. The ID region is formed within the data region and a synchronization signal for reading the ID information is written into the data region. The data sector includes a data sync region for writing a synchronization signal for reading information written on the data sector, the ID region for writing ID information for the data sector, a PAD region for separating the ID region and the data region, a data address mark region for indicating a validity of data written on the data sector, the data region for writing the data transferred from the external device, and an error correction code region for writing an error correction code to automatically correct an error upon occurrence of a defect when data is written on the data region.

Abstract: A method of providing the servo pattern for detecting fine defects in the servo burst signals of a hard disk drive (HDD) comprises the steps of writing a preamble portion for providing a servo sync signal in reading servo data together with a gap to inform of a servo sector, writing a servo address mark (SAM) for notifying the start of the servo to provide a sync signal to read the following gray code, writing the gray code for providing the identification data ID of a track, and writing a burst signal portion consisting of multiple repetition of the position error signal required for even or odd numbered track data and track following.

Abstract: A method and apparatus for determining a number of defects detected on a disk in a hard disk drive. The hard disk drive comprises an actuator arm mounted to a housing and a head mounted to the actuator arm. A spin motor is mounted to the housing and a disk is attached to the spin motor. The disk has a plurality of tracks, each of which has a plurality of sectors. Each of the sectors has a data field. The hard disk drive further comprises a defect detection circuit coupled to the head that detects a number of defects located in the data field. In one embodiment, the hard disk drive comprises a defect size detection circuit coupled to the head, that detects a corresponding size of each defect detected.

Abstract: A servo control method of a hard disk drive includes: providing a disk having a plurality of first servo track patterns, including a gray code field, for providing track information for each track, and a plurality of second servo track patterns which fail to include the gray code field of the first servo track patterns, both the first and second track patterns being positioned on the same track; providing a head for reading data from a given track of the disk or writing data on the given track; checking, in response to a data read/write command received from a host computer, whether or not the head must move to a target track; if it is determined that the head must move to the target track, repeatedly switching from one head to a following head, in a sequential manner, to perform a track seek; after performing the track seek, checking whether or not a velocity of the head is decreasing; and, if it is determined that the velocity of the head is decreasing, fixing the head on the disk including the target track

Abstract: A circuit for preventing servo sectors from being overwritten during write operations due to misdetection of servo address mark (SAM) in a disk drive which includes a CPU, a SAM detection circuit for detecting the SAM, a reference pulse generator for generating reference pulses to obtain a servo detection timing in response to a SAM detection signal, a main counter for counting the system clock signals upon receipt the reference pulses, a data sector end pulse generator for generating a data sector end signal, a SAM detection window generator for generating a SAM detection window signal enabled to a window value loaded by the CPU upon receipt of the end signal and a pseudo SAM upon misdetection of the SAM in the SAM detection window signal, a pseudo SAM counter reset by the SAM detection signal for counting the PSAMs provided by the SAM detection window generator to generate a counting pulse when the counted value exceeds a given value, a delay and search flag bit generator for delaying the servo detection ti

Abstract: An automatic servo address mark detecting and servo timing compensating circuit of a disk drive includes a servo address mark detection window generating unit for generating a servo address mark detection missing signal and count control signal where the servo address mark is not detected within a range of a servo address mark window of a predetermined servo sector; a servo address mark missing signal counter, which is reset according to a servo address mark detection signal, for generating a servo address mark search signal and pseudo servo address mark where a servo address mark detection missing signal count matches data loaded from the control unit; a servo address mark search controller for selecting the servo address mark search signal and pseudo servo address mark among multiple signals input by the servo address mark missing signal counter according to a select signal input by the control unit; and a servo timing compensation unit for counting system clocks, starting from the data loaded from the cont

Abstract: A disk recording medium includes a servo track pattern where a gray code field has been deleted, capable of embodying a high capacity hard disk drive. The hard disk drive which uses as a recording medium, a disk having a plurality of servo sectors for each track, includes: a first plurality of servo track patterns on each track, the number of first servo track patterns equal to the total number of first servo sectors existing on each track divided by the number of heads of the hard disk drive, each of the plurality of servo track patterns having a gray code field for providing information for each track; and a second plurality of servo track patterns on each track, the number of second servo track patterns equal to the total number of servo sectors existing on each track minus the number of first servo track patterns, each of the second plurality of servo track patterns corresponding to the first servo track pattern but with the gray code field deleted.

Abstract: A serial interface circuit for interfacing serial data between a control unit and a read/write channel circuit of a magnetic disk drive, includes a bit control data loading unit for loading the serial data to interface with the read/write channel circuit of a specified standard and the bit control data related to the transfer control signal of the serial data under the control of the control unit, and a serial interface control circuit for supplying the serial data to the read/write channel circuit by performing the bit conversion to adapt to the serial data, controlling the polarity and edge of the transfer control signal, and controlling the bit conversion by employing the loaded bit control data.

Abstract: A decoding compensation circuit, which compensates for missing pulses when decoding the gray code written in a magnetic disk of a hard disk drive (HDD) includes: a central processing unit (CPU) for controlling the hard disk drive, a positive pulse detection window generator for generating a positive pulse detection window signal, a digital servo data generator for generating a digital servo data, a gray code detection window generator for generating a gray code detection window signal, a first logic gate circuit for logically processing the positive pulse detection window signal, digital servo data and gray code detection window signal so as to produce positive and negative pulse gray codes, a gray sync/data separation circuit for separating gray data and gray sync from the positive and negative pulse gray codes, a second logic gate circuit for logically processing the positive and negative gray data and sync to compensate for missing gray data and sync, a gray sync decision circuit for detecting the gray syn

Abstract: A technique for generating sector pulses in a hard disk drive using hardware involves: receiving read reference clocks produced during a read operation of the hard disk drive and producing a byte clock in sync with every byte; outputting the byte clock as an effective production clock in a time interval in which no servo gate signal indicative of a servo zone on a magnetic disk or the hard disk drive is produced, counting the production clocks, and comparing the counted value obtained during the production clock counting step with a previously stored value indicative of a sector length and generating a sector pulse when the counted value is equal to the previously stored value.

Abstract: A gray code decoding circuit of a hard disk drive includes a servo pattern area, a data pick-up device, and a pattern detecting device. The servo pattern area has data recorded as a gray code. The data pick-up device detects the recorded data, converts it into encoded read data, and outputs the encoded read data. The pattern detecting device detects a position of the servo pattern area in response to the encoded read data and outputs a reference pulse. The gray code decoding circuit also contains a gray window generating device, a synchronous signal generating device, a gray code extracting device, and a gray-binary converting device. The gray window generating device divides the encoded read data by a division ratio, converts the divided encoded read data into gray data, outputs the gray data, and generates a first synchronous signal after counting by a system clock to a first value. The synchronous signal generating device outputs first and second window signals in response to a second synchronous signal.

Abstract: Disclosed is a drive control circuit for driving a VCM, wherein the voice coil motor is driven by the current corresponding to the level of a PWM signal and a current gain selected by a switching operation according to the servo control modes. The switching operation is performed after a delay for the duration between the starting point of the pulses of the PWM signal and the time of the overshooting of the VCM being minimized.

Abstract: A spindle motor driving control circuit in a disk drive recording device including a spindle motor for rotating a disk recording medium, a motor driving unit for controlling driving of the spindle motor, and a control unit for controlling the overall operation of the disk drive recording device.