Abstract: Servo regions are re-magnetized in the present invention. A magnetic storage device measures a first amount which is indicative of the magnitude of magnetization of a servo region, by a read head portion. The first amount may be a reproduced output, or an inverse of a gain used in an automatic gain control, etc. Servo regions are re-magnetized by a write head portion, when a servo region is detected in which a ratio of the measured first amount to an initial value of the first amount is smaller than a predetermined value, i.e., it is determined that the magnetization is reduced.

Abstract: A servo circuit includes a servo channel and a processor. The servo channel recovers servo data from servo wedges that identify respective data sectors on a data-storage disk. On spin up of the disk, the processor detects a spin-up wedge associated with one of the servo wedges and then detects the servo wedge. Once the servo wedge is detected, a head-position circuit can read the location data from the servo wedge to determine an initial position of the read-write head. By detecting a both a spin-up wedge and a servo wedge to determine an initial head position on disk spin up, such a servo circuit often allows one to increase the disk's storage capacity by reducing the lengths of the spin-up wedges.

Abstract: A phase locked loop (PLL) system for generating a reference clock to write recording data on an optical medium includes a clock generator generating the reference clock according to a phase difference between the reference signal and a first frequency-divided signal; a phase-shift detector generating a phase adjusting signal; and a phase-controllable frequency divider dividing the frequency of the reference clock to generate the first frequency-divided signal, and receiving the phase adjusting signal to adjust the phase of the first frequency-divided signal. The phase-shift detector includes an ADIP sync detector generating an ADIP synchronization signal synchronous to the ADIP units of the optical medium; a frequency divider dividing the reference clock to generate a second frequency-divided signal; and a phase difference detector detecting a phase difference between the second frequency-divided signal and the ADIP synchronization signal to generate the phase adjusting signal.

Abstract: The magnetic recording and reproducing apparatus reads a transfer clock synchronized with servo information and records a write-once clock pattern in a state where 0 is set as a delay time of the delay device 13 and 1 is set as the dividing ratio of the frequency divider 17. The apparatus corrects the delay time according to the output of the phase comparator 14 which changes on the basis of the phase difference and rewrites a write-once clock pattern. Rotation of the magnetic disk, detection of the phase difference and correction of the delay time are repeatedly preformed until no change occurs in the output of the phase comparator 14. After the output stops changing, preformat information patterns excluding the servo information pattern are recorded as fine patterns by changing the dividing ratio of the frequency divider 17 to multiply the frequency.

Abstract: A storage channel, e.g., for a disk drive system, may asynchronously sample and buffer an entire sector, and then process the buffered sector to recover timing information. The storage channel may operate in an open-loop and utilize an exhaustive search to determine timing parameters. Alternatively, the storage channel may operative in a closed-loop, processing the sector once, and feeding back information obtained during decoding to the timing loop.

Abstract: A method of reproducing data and a control device using a controllable dummy read gate. In the method of reproducing data, at least one of a pulse width, a pulse generating location and a number of pulses is controlled so that a dummy read gate is generated. Then, a read gate for reproducing a target sector is generated, and data is reproduced using the read gate. According to the method, the pulse width of the dummy read gate is generated, a location of the defect sector is avoided and error estimation is decreased. Further, in a case where it is determined that the defect sector or signal distortion exists, the read error is prevented by adjusting the pulse generating location of the dummy read gate.

Abstract: In a disk drive that performs perpendicular magnetic recording, the read/write channel has a sync mark generator. The sync mark generator generates a second sync mark before the read/write channel operates to write data on a disk. The second sync mark has a bit pattern including a series of bits representing positive polarity and a series of bits representing negative polarity. The series of bits, which is longer than the other, has a bit length that is at least 50% but less than 85% of the total bit length of the second sync mark.

Abstract: A method and apparatus for determining sector block sizes using existing controller signals has been disclosed. The invention detects a characteristic of a data channel gate signal indicating a length of data, determines the length of data based on the detection of the characteristic, and calculates the size of a last data block in the length of data based on the determined length.

Abstract: A servo writing system for writing servo sectors onto a disk includes a direct digital synthesizer (DDS) that forms a phase and frequency adjustable continuous wave signal based upon a reference digital clock signal. A PLL coupled to the DDS measures repeatable timing errors (RTEs) associated with the continuous wave signal and generates an output clock signal that is used to clock the writing of servo sectors onto the disk. A digital control system is coupled to the DDS and the PLL, which calculates repeatable error compensation adjustment values based on the RTEs measured using the PLL. The compensation adjustment values may be applied to the DDS such that the DDS compensates for the RTEs and such that the output clock signal used to clock the writing of the servo sectors onto the disk includes minimal RTEs.

Abstract: A rotatable storage media includes a first data segment stored in first tracks and a second data segment stored in second tracks. The first tracks include a first start track and a first end track, and the second tracks include a second start track and a second end track. The first data segment starts in the first start track at a start rotational phase, ends in the first end track at an end rotational phase, starts in adjacent first tracks at start rotational phases offset by an intra-segment rotational skew angle and ends in adjacent first tracks at end rotational phases offset by the intra-segment rotational skew angles. The second data segment starts in the second start track at the start rotational phase, ends in the second end track at the end rotational phase, starts in adjacent second tracks at start rotational phases offset by the intra-segment rotational skew angle and ends in adjacent second tracks at end rotational phases offset by the intra-segment rotational skew angle.

Abstract: A digital PLL system includes a first multiplier coupled to a phase difference signal for multiplying the phase difference signal by a first gain factor; a second multiplier coupled to the phase difference signal for multiplying the phase difference signal by a second gain factor; a digital loop filter coupled to the first multiplier and the second multiplier for providing an integral signal and a proportional signal and for generating a control signal according to the integral signal and the proportional signal; and an auto-gain control (AGC) unit coupled to the first multiplier, the second multiplier, and the digital loop filter. The AGC unit further comprises a first control unit for updating the first gain factor according to the integral signal; and a second control unit for updating the second gain factor according to the proportional signal.

Abstract: Techniques are described for accurately processing playback signals of time-based servo patterns recorded on a data storage medium. In particular, techniques are described for determining values for signal peaks within a playback signal of a time-based servo pattern by applying interpolation to data points in proximity to each of the signal peaks. At least three data points are identified in proximity to a desired peak to be detected within the playback signal. A value is calculated for the desired peak based on interpolation of the at least three data points. A playback signal of a time-based servo pattern may include a sequence of signal peaks. A time-based servo pattern may be detected based on lengths of time measured between consecutive peaks in the sequence of peaks. A position error signal (PES) may be generated based on the values calculated for each of the sequence of peaks.

Abstract: In one example, a dual source tracking servo system includes a head assembly having a data transducer, a primary position detector for sensing the position of a magnetically stored data track, and a secondary position detector for sensing the position of a fixed reference associated with a magnetic storage medium. A controller is configured for adjusting the position of the head assembly in response to a weighted average of the sensed position of the magnetically stored data track and the fixed reference, wherein the position of the magnetically stored data track is weighted more than the position of the fixed reference. The primary position detector may include one or more dedicated servo read elements associated with the head assembly and the secondary position detector may include a magnetic or optical sensor. The fixed reference may include a tape edge or servo track.

Abstract: For compensating for jitter within a data storage device in real time, a jitter amount is determined from timings of servo signals for sectors of the data storage device. A timing of a servo gate pulse is adjusted for accessing another sector depending on the jitter amount. Such a jitter amount depends on the eccentricity of a disc having the sectors within the data storage device.

Abstract: A method and apparatus are disclosed for detecting data, such as a sample sequence read from a recording channel. Interpolation techniques are employed to generate one or more interpolated sample sequences from the data. Each interpolated sample sequence has a different corresponding phase relative to the data. A distance measure is generated between a portion of each interpolated sample sequence and an ideal sample sequence. The ideal sample sequence corresponds to peaks in the data. According to one aspect of the invention, a signal asymmetry measure is computed for the portion of each sample sequence and is used to adjust an ideal sample sequence.

Abstract: An apparatus, method, and system for writing data to a hard disk drive synchronous with an apparent disk speed. The apparatus, method, and system has a phase-locked loop (PLL) to generate am output clock signal, wherein a clock interpolator responsive to phase rotation control is in the PLL feedback loop. The phase rotation control is proportional to the apparent disk speed, and the PLL output clock signal is also proportional to the apparent disk speed. A second clock interpolator further modifies the PLL output clock signal to provide pre-compensation control.

Abstract: A remodulator embodied in an integrated circuit (IC), a method for remodulating bits and a controller and disk drive incorporating the IC or the method. In one embodiment, the IC includes: (1) a remodulator that processes incoming bits to yield remodulated outgoing bits, the remodulator including a selected one of a decision feedback loop and an error feedback loop and (2) a feedforward loop coupled to an input of the remodulator and having a baseline wander filter, the baseline wander filter cooperating with the selected one of the decision feedback loop and the error feedback loop to reduce a bit error rate of the remodulated outgoing bits.

Abstract: A first set of data is detected in a signal having synchronous samples and interpolated samples, wherein the first set of data is detected asynchronously as corresponding to one of the samples. A time to transmit a data-found signal is determined based on an offset between the data-detected sample and one of the synchronous samples, and the data-found signal is transmitted at the determined time to enable the synchronous processing of the synchronous samples. In one implementation, the synchronous samples correspond to a readback signal read from a data recording channel, the first set of data corresponds to servo address mark (SAM) data in a servo sector in the readback signal, and the synchronous processing is demodulation of burst data in the servo sector.

Abstract: A servo pattern writing method of writing a servo pattern for the positioning control of a magnetic head on a magnetic disk comprises changing the rotating speed of the magnetic disk with the magnetic head positioned at one or more proper radial positions with respect to the magnetic disk. The rotating speed of the magnetic disk is changed on the basis of the magnitude of a synchronous vibration synchronous with the rotation of the magnetic disk. Writing current for writing a servo pattern is set according to the change of the rotating speed of the magnetic disk. The STW rotating speed is changed according to the change of the radial position of the magnetic head to reduce the intensity of the vibration that is generated during a servo pattern writing operation to a value meeting a positioning level. The servo track writing operation can be achieved at a low cost.

Abstract: Disclosed is a method for reducing spiral write time and clock reference drift while writing spiral reference patterns on a disk of a disk drive. The method includes: controlling a radial location of a head for writing a first band of tracks near one of an outer diameter (OD) circumference of the disk or an inner diameter (ID) circumference of the disk and for writing a second band of tracks near the other of the OD circumference of the disk or the ID circumference of the disk, respectively, wherein a substantial majority of the tracks each include a plurality of servo sectors including a track number and a sync mark; measuring a distance between first and second reference center positions of reference center tracks of the first and second bands of tracks; and writing a spiral reference pattern therebetween.

Abstract: A phase adjustment circuit includes: a carrier-wave-delay adjusting circuit for delaying an input carrier wave and outputting the delayed carrier wave, in accordance with phase information; and a phase-difference detecting/adjusting circuit for detecting a phase difference between an input signal and the delayed carrier wave, outputting, as the phase information, a value according to the detected phase difference, adjusting the delayed carrier wave such that the delayed carrier wave has a phase substantially coincident with a phase of the input signal, and outputting the resultant carrier wave as a phase-adjusted carrier wave. In a steady state, the phase-difference detecting/adjusting circuit outputs, as the phase information, a value indicating the presence of a phase difference.

Abstract: The invention is directed to patterns of amplitude-based servo windows that eliminate the need for conventional track identification marks, and various servo writing devices and head configurations that facilitate creation of such servo patterns. The patterns of servo windows may also eliminate the need for conventional synchronization marks. In accordance with the invention, the patterns of servo windows, themselves, can distinguish one track from another track in one or more servo bands and inherently provide synchronization without the need for synchronization marks between servo frames. In other words, the same amplitude-based servo windows that define the centerlines of the tracks can be arranged to provide track identification information and possibly inherent synchronization information.

Abstract: A magnetic recording system having a magnetic-recording medium with data sectors wherein a preamble pattern of a prescribed cycle is recorded, the preamble pattern having the cycle of a predetermined T, wherein T represents a minimum duration of a data-recorded bits in the data sectors. The system includes a magnetic head to reproduce the preamble pattern and a signal-processing circuit to process data to be recorded in and reproduced from the data sectors. The signal-processing circuit including (i) a sampler for sampling a signal reproduced from the preamble pattern and (ii) a corrector for correcting the amplitude by using maximum and minimum amplitude values in each cycle of the preamble pattern sampled by the sampler.

Abstract: A method and apparatus for writing spiral servo information is provided. In one embodiment, a servo track writer having a digital signal processor is provided. The servo track writer also includes a clock head, which reads a clock track from a disk surface to generate a clock signal that is used to provide interrupt signals to the digital signal processor. A transducer, which writes spiral servo information onto the disk surface, is positioned under control of the digital signal processor based upon the interrupt signals. In one embodiment, a method of writing spiral servo information onto a disk surface using a servo track writer having a digital signal processor is provided. The method includes the steps of reading a clock track written onto the disk surface to generate interrupt signals; providing the interrupt signals to the digital signal processor; and, positioning a transducer over the disk surface under control of the digital signal processor based upon the interrupt signals provided thereto.

Abstract: Disclosed are techniques related to cluster-based defect detection testing for disk drives. A disk drive comprises a disk, a moveable head to scan the tracks of the disk, and a defect detection circuit to detect defects on the disk scanned by the moveable head. The disk drive includes a microprocessor for controlling operations in the disk drive including cluster-based defect detection. The microprocessor under the control of a cluster detection program defines a scan window. The scan window corresponds to an area of the disk scanned by the moveable head. The microprocessor under the control of the cluster detection program further defines a cluster threshold corresponding to a minimum number of defects required to occur within the scan window and identifies a defect cluster if a cluster threshold of defects occurs within the scan window. By identifying defect clusters on the disk these defect clusters can be margined.

Abstract: A signal processing device for analog-to-digital converting a burst signal has a feature of selecting a data bus to notify a disk control device of a conversion result via an NRZ data bus. The disk control device stores the result of the analog-to-digital conversion of the servo positional signal. The positional signal of a head of the disk device is digitized in a R/W channel. Sampling for digital conversion is performed in only a window which is defined only in the vicinity of peaks of the positional signal. The values of peaks which are obtained by sampling are averaged by an averaging circuit. This enables the influence of noise occurred outside of the window to be eliminated. Although the noise in the window is sampled, its adverse influence is suppressed by the averaging processing.

Abstract: A disk drive is disclosed comprising a disk having a plurality of servo sectors forming a plurality of substantially linear servo wedges extending from an outer diameter of the disk to an inner diameter of the disk, wherein each servo sector is written using perpendicular magnetic recording. The disk drive further comprises a head coupled to a distal end of an actuator arm that is rotated by a rotary actuator about a pivot in order to actuate the head radially over the disk in a substantially arcuate path.

Abstract: An information writing device in which the information can be written accurately efficiently and in which variable formats of the disc-shaped recording mediums can be coped with without the necessity of providing master discs from one format of the disc-shaped recording medium to another. A grating interferometer clock scale system is formed by a clock pattern disc 50 having a clock track 52 carrying an optically readable clock pattern 51 and an optical head 60 for optically reading out the clock pattern 51. Clock signals are generated in a clock generator 90, to which is transmitted, via an optical fiber 80, the interference light obtained as an optical output obtained in turn by optically reading out the clock pattern 51 by the optical head 60, based on electrical signals obtained on photoelectrically transducing the optical output. The servo information synchronized with the clock signals is generated by a servo information generating part 93.

Abstract: A data storage device exhibiting reduced pad regions includes a read/write channel to convert transduced waveforms from a storage medium into recovered digital information. The recovered digital information is communicated from the read/write channel to a controller. The read/write channel includes an analog stage and a digital stage, which function independently. While the digital stage is engaged in the task of recovering servo data, the analog stage may be engaged in the task of recovering user data. Initially, the controller generates a control signal commanding the read/write channel to read and recover servo data. In the wake of the last unit of servo data having been processed by the analog stage of the read/write channel, the controller commands the read/write channel to read user data from the disc. Therefore, the analog stage of the read/write channel reads user data, while the digital stage finishes processing the servo data.

Abstract: Improvements in placement of timing patterns in self-servowriting include correcting for systematic errors due to geometric effects. A correction is made for varying systematic errors, such as when the recording head has spatially separate read and write elements. Further, servopattern rotation due to residual or unmeasured systematic errors is reduced by using a once per revolution clock index derived from the motor drive current waveform or any other sensor. In one aspect of correcting for systematic errors in the writing of timing patterns on a storage medium of a storage device, a time interval between a trigger pattern written at a first radial position of the storage medium and a rotational index is measured. The rotational index is related to the rotational orientation of the storage medium with respect to a fixed frame of the storage device.

Abstract: A magnetic recording disk drive has a patterned magnetic recording disk with data blocks of magnetizable material separated by nonmagnetic regions, a write-clock-generation circuit for timing write pulses to the write head, and a rotational vibration sensor that adjusts the timing of the write pulses to correct for errors caused by rotational disturbances to the disk drive. The write-clock-generation circuit receives a reference clock signal synchronized to disk rotation and multiplies it to generate a higher-frequency write-clock signal. The write-clock-generation circuit includes a phase detector that compares the phase of the reference clock signal and the write-clock signal and provides an error signal. The output of the rotational vibration sensor is summed with the phase detector error signal to compensate for disk rotation speed changes caused by rotational disturbances.

Abstract: The present invention compensates for variations in the angular velocity of the drive's spindle motor by periodically dropping clocks to a counter based upon the previous servo wedge-to-wedge timing. This enables a substantially constant count to be maintained between servo wedges and allows a more predictable generation of the data sector pulses. A more predictable generation of the data sector pulses enables the size of the guard band preceding each data sector to be decreased and the capacity of the disk to be correspondingly increased.

Abstract: A method and apparatus for providing write pre-compensation using a read timing path is disclosed. The present invention generates a first phase clock signal having a first phase and being synchronized with a read signal of a read path, generates a second phase clock signal having a second phase at a predetermined phase difference with the first clock signal and uses the first and second clock signals to shift write data to achieve write data comprising a first desired pre-compensation.

Abstract: A method and apparatus for providing write pre-compensation using a read timing path is disclosed. The present invention generates a first phase clock signal having a first phase and being synchronized with a read signal of a read path, generates a second phase clock signal having a second phase at a predetermined phase difference with the first clock signal and uses the first and second clock signals to shift write data to achieve write data comprising a first desired pre-compensation.

Abstract: A disk drive is disclosed comprising a disk surface having a plurality of concentric, radially spaced tracks, wherein each track comprises a plurality of data sectors and a plurality of servo sectors. At least two different index marks are distributed around the circumference of the disk surface. A servo sector counter is initialized relative to which index mark is detected, wherein the servo sector counter identifies a circumferential location of the servo sectors.

Abstract: A magnetic disk control apparatus is capable of reducing the overall length of synchronization fields in split sectors and hence capable of increasing the storage capacity for data fields. The apparatus records data for each sector in such a manner that when a servo field is present in a sector, the sector is split into a first split sector and a second split sector each including a synchronization field and a data field. The apparatus has a storage medium, a head, a mechanical section that controls the relative position of the storage medium and the head, a hard disk controller that controls write timing and read timing, and a read channel that modulates and writes a synchronization field and a data field according to the write timing, performs phase synchronization and frequency synchronization based on the synchronization field read according to the read timing, and demodulates the data field according to the obtained phase and frequency.

Abstract: The minor coherence-errors suffered during servowriting of bursts in a phase burst servo pattern may contribute to significant written-in runout of the resulting pattern. Embodiments of the present invention enables the servowriting of both the zig/zag bursts and/or the digital information of the phase burst pattern all in one single revolution so that the common coherence errors of the zig/zag bursts can be canceled during demodulation. Such single pass servowriting of both zig/zag bursts can be accomplished by either using additional phase-adjustment circuitry or by shifting the phase of the write clock to allow servowriting of the bursts and/or digital information all at edges of (different) integer clock cycles. This description is not intended to be a complete description of, or limit the scope of, the invention. Other features, aspects, and objects of the invention can be obtained from a review of the specification, the figures, and the claims.

Abstract: Head-to-head variations in the head gap distance between write and read heads is compensated by measuring the head gap distance in each head by writing and reading a predetermined unique pattern, and compensating the timing to start the data writing by changing it in a head-to-head manner based on a time gap that corresponds to the measured head gap distance in each head. This allows data to be written at a desired physical position regardless of the variation of the head gap distance, thereby allowing formatting efficiency to be improved.

Abstract: Channel parameters for a magnetic readback channel are optimized by detecting a readback signal that is recorded on a magnetic medium. The readback signal contains a plurality of predetermined-length control fields. Each control field is arranged between two user data fields and contains at least one transition. At least one selected readback parameter, such as a frequency of a readback channel system clock, a gain of the readback channel, a equalization response of the readback signal, and/or an amplitude asymmetry of the readback channel, is optimized based on information contained in at least one control field.

Abstract: In a tape having separate servo bands of patterns positioned laterally across the tape, the patterns of a separate servo band have at least one differentiating characteristic with respect to patterns of another of the separate servo bands. The differentiating characteristic allows identification of the separate servo bands. For example, the patterns of a separate servo band have differing azimuthal orientations of detectable transitions with respect to another servo band, such as being laterally inverted. In another, variations in the width of gaps of patterns are made with respect to another servo band. In another, variations are made in the number of the detectable transitions of patterns with respect to the patterns of another servo band.

Abstract: In a tape having separate servo bands of patterns positioned laterally across the tape, the patterns of a separate servo band have at least one differentiating characteristic with respect to patterns of another of the separate servo bands. The differentiating characteristic allows identification of the separate servo bands. For example, the patterns of a separate servo band have differing azimuthal orientations of detectable transitions with respect to another servo band, such as being laterally inverted. In another, variations in the width of gaps of patterns are made with respect to another servo band. In another, variations are made in the number of the detectable transitions of patterns with respect to the patterns of another servo band.

Abstract: Using a “reference” sensor, a reference position is detected in a frame of reference that is moving along a predetermined path relative to the reference sensor. The reference position is used to derive a position-dependent indicator of a position-dependent “longitudinal” offset component (i.e. along the path). An output from the target sensor is monitored using a “target window” that is partially based on the position-dependent indicator.

Abstract: An A/D converter includes a low-bit resolution A/D which converts an input signal into a digital value of 4 bits or less, and a low-pass digital filter which suppresses a high-frequency-band component in an output from the low-bit resolution A/D, and extracts phase information contained in the input signal as amplitude information. A digital PLL circuit and information recording apparatus are also disclosed.

Abstract: A recording system records sector information on a recording medium, such as a hard disc drive, using a write gate signal. Timing of the write gate signal enables writing a servo data patterns over the servo wedge fields of the disc and, if the hard disc drive contains prior recorded data, writing null data over selected sector segments of the hard disc.

Abstract: An apparatus, method, and system for writing data to a hard disk drive synchronous with an apparent disk speed. The apparatus, method, and system has a phase-locked loop (PLL) to generate am output clock signal, wherein a clock interpolator responsive to phase rotation control is in the PLL feedback loop. The phase rotation control is proportional to the apparent disk speed, and the PLL output clock signal is also proportional to the apparent disk speed. A second clock interpolator further modifies the PLL output clock signal to provide pre-compensation control.

Abstract: A disk drive includes a head and a disk, spiral patterns are located on the disk, and the disk drive self-writes servo patterns on the disk using the spiral patterns as a reference for servoing the head. In an embodiment, the disk drive uses preliminary servo patterns to determine repeatable runout of the spiral patterns. In another embodiment, the disk drive reads each spiral pattern with multiple timing windows.

Abstract: A first delay circuit receives a sampling clock obtained by multiplying detected frequency of reference clock patterns and outputs delay clocks from first delay stages, respectively. Recording frequency of the sampling clock is not obtained using the reference clock patterns but obtained using received addresses. A disk driving apparatus obtains the number of the first delay stages to be used which correspond to one cycle of the obtained recording frequency and necessary for phase adjustment of the sampling clock, and disables not-used first delay stages. Any of the delay clocks is selected and at least one of regenerating operation to read data from a disk media and recording operation to write data thereto is executed in synchronization with the selected delay clock. Consequently, the number of delay stages to be disabled can be obtained with simple control, reducing power consumption of circuits for adjusting phases of the sampling clocks.

Abstract: A magnetic disk apparatus and a servo pattern recording method therefor, enabling writing of servo signal with high quality, without being affected with ill influences due to fluctuation on a rotation speed when conducting the self servo write operation, comprises: a magnetic disk 102; a head 103 having a write element for use of recording information onto the magnetic disk and a read element for reproducing information from the magnetic disk; and an actuator for moving said head to a desired radial position on the magnetic disk, wherein on the magnetic disk is recorded servo patterns 110 for positioning the head on a recording surface thereof, and within each of the servo patterns are recorded, a pattern sector marker 208a as a marker for detecting passage time of the head, a track ID code 209, and a burst pattern 210 for use of detection of the radial position of the head, following a preamble 207a for use of synchronization of time-base circuit, and further recorded and disposed a second preamble 207b and

Abstract: Techniques for detecting data, such as servo data, from input or incoming data read from a transmission medium, such as magnetic recording medium, in the presence or absence of radial incoherence. In one illustrative recording medium-based aspect of the invention, such a technique for detecting data from input data stored on a recording medium comprises the following steps. First, one or more samples are interpolated from one or more samples which have been generated from the input data at a given symbol rate. The one or more interpolated samples have one or more phases associated therewith which differ from a phase associated with the one or more samples generated at the given symbol rate. Then, an optimum or best phase is selected from the symbol rate phase and the one or more interpolated phases such that at least a portion of the one or more samples associated with the optimum phase are identified as representative of detected data.

Abstract: The invention combines the benefits of sectored servo data with the benefits of time-based servo data. Recording media such as magnetic tape, magnetic disks, optical tape and optical disks can store servo data in a time-based sectored servo format.