EP0471314A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Edge servo for disk drive head positioner
Assignee: Quantum Corp
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Filing: 1991-08-09
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Granted: —
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Expires: 2011-08-09
Abstract
Abstract A method for determining the position of a data transducer head within one data track of a rotating data storage disk within a disk drive includes the steps of: providing at least one prerecorded servo sector within the data track, the servo sector including first occurring servo burst means having one longitudinal burst edge located substantially congruent with a centerline of the one track, and having another longitudinal burst edge located substantially congruent with a centerline of a second track adjacent to the one track, and second servo burst means having longitudinal burst edges substantially congruent with the track boundaries of the one track, detecting the presence of the sector as it passes by the data transducer head, sampling with the data transducer head and holding peak amplitude of the first servo burst, sampling with the data transducer head and holding peak amplitude of the second servo burst, comparing held first burst amplitude with a predetermined value to determine if the data transducer head has passed over a linear edge portion thereof, and if so, determining from the held first burst amplitude the position; and if not, determining from the held second burst amplitude the position of the data transducer head relative to the one track.
Inventors
- 👤 Ronald R. Moon
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 13:16
CPC Classifications
G; G11; G11B; G11B21/00; G11B21/02; G11B21/10; G11B5/00; G11B5/48; G11B5/58; G11B5/596; G11B5/59633; G11B5/59655
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
289 words
A method for determining head position of a data transducer head relative to a selected one track of a multiplicity of concentric data tracks within a disk drive data storage device, the method including the steps of: providing at least one prerecorded servo sector within the data track, the servo sector including first occurring servo burst means being prerecorded with a predetermined servo burst magnetic flux transition pattern and having one longitudinal burst edge located substantially congruent with a track centerline of the said track, and having another longitudinal burst edge located substantially congruent with a track centerline of a second track immediately adjacent to the said track, and second occurring servo burst means being prerecorded with the predetermined servo burst magnetic flux transition pattern for providing burst edges substantially congruent with track boundaries of the said track, detecting the presence of the sector as it passes by the data transducer head, reading the first occurring servo burst means with the data transducer head to determine a peak amplitude value therefrom and recording a first burst peak amplitude value, comparing the first burst peak amplitude value with at least one predetermined reference burst amplitude value to establish whether the transducer head has passed along a linear portion of one of the said edges of the first occurring servo burst, and if so, determining from the recorded first burst peak amplitude the position of the data transducer head, and if not, reading the second occurring servo burst means with the data transducer head to determine a peak amplitude value therefrom and recording a second burst peak amplitude value, determining from the recorded second burst peak amplitude value the absolute position of the data transducer head relative to the said track.
Claim 2
Dependent Claim
27 words
The method for determining head position as set forth in claim 1 comprising the further step of determining during a calibration routine the reference burst amplitude value.
Claim 3
Dependent Claim
49 words
The method for determining head position as set forth in claim 2 wherein the step of determining the reference burst amplitude value comprises the step of determining at least one amplitude equivalence point at a location radially between the first servo burst means and the second servo burst means.
Claim 4
Dependent Claim
36 words
The method for determining head position as set forth in claim 3 wherein the step of determining at least one amplitude equivalence point comprises determining a high amplitude equivalence point and a low amplitude equivalence point.
Claim 5
Dependent Claim
67 words
The method for determining head position as set forth in claim 1 comprising the further step of determining during a calibration operation the slope of each said edge by determining radial positional displacement of the data transducer head as a function of burst amplitude, and wherein the step of determining the position of the data transducer head is carried out further in relation to the said slope.
Claim 6
Dependent Claim
126 words
The method for determining head position as set forth in claim 1 wherein the step of providing at least one servo sector within the data track further comprises the steps of providing a servo sector address mark field including a magnetic flux transition pattern prerecorded therein for identifying the start of a servo information pattern, providing a track number field including a magnetic flux transition pattern prerecorded therein for identifying the said one data track from among the multiplicity thereof; and, comprising the further steps of: reading the servo sector address mark field with the data transducer head to determine the start of the said servo information pattern, and reading the track number field to identify the said one data track from among the multiplicity thereof.
Claim 7
Dependent Claim
42 words
The method for determining head position as set forth in claim 6 wherein the steps of providing a servo sector address mark field and a track number field are carried out prior to providing the first and second occurring servo burst means.
Claim 8
Dependent Claim
58 words
The method for determining head position as set forth in claim 6 wherein the determined head position is added to a value obtained from the track number field of the said track, thereby to provide a number indicative of the track number of the said track and the position of the data transducer head within the said track.
Claim 9
Dependent Claim
65 words
The method for determining head position as set forth in claim 8 wherein the track number of the said track is initially set to include a positional value indicative of track centerline position, and wherein the determined head position is added to or subtracted from the positional value of track centerline position, thereby to provide the position of the data transducer head within the track.
Claim 10
Dependent Claim
37 words
The method for determining head position set forth in claim 9 wherein the positional value is determined to be a value which is one half of the data transducer head position quantization resolution within the data track.
Claim 11
Dependent Claim
30 words
The method for determining head position set forth in claim 10 wherein the said quantization resolution within the data track is 32 increments, and wherein the positional value is 16.
Claim 12
Dependent Claim
80 words
The method for determining head position set forth in claim 1 wherein a width of the selected one track is greater than the width of the data transducer head, and further wherein the data transducer head experiences a dead zone range of radial movement with respect to a said burst such that burst amplitude read by the data transducer head from the said burst remains substantially constant as the data transducer head moves radially through the said dead zone range.
Claim 13
Dependent Claim
163 words
The method for determining head position set forth in claim 6 wherein the step of reading the track number field at the vicinity of a track boundary between two adjacent ones of the said data tracks results in an ambiguity as to which data track is in closest proximity to the head, and comprising the further steps of: determining the radial velocity of the head relative to the multiplicity of data tracks during a track seeking operation, comparing determined radial velocity with a predetermined reference velocity value, selecting a track number read by the data transducer head as an indicator of radial head position when the determined radial velocity is greater than the reference velocity value, performing the steps of reading the second occurring servo burst and determining from the recorded second burst peak amplitude the absolute position of the data transducer head, and correcting the track number read by the data transducer head by reference to the recorded second burst peak amplitude.
Claim 14
Dependent Claim
44 words
The method for determining head position set forth in claim 1 wherein the steps of comparing the first burst peak amplitude with the predetermined reference burst amplitude value and reading the second occurring servo burst means are carried out, at least in part, concurrently.
Claim 15
Dependent Claim
160 words
A servo sector pattern for an embedded sector head position servo loop within a disk drive, the pattern including for one concentric data track of a multiplicity thereof: a servo sector address mark field including a magnetic flux transition pattern prerecorded therein for identifying the start of the servo sector pattern, a track number field including a magnetic flux transition pattern prerecorded therein for identifying the said one data track from among the multiplicity thereof, first occurring servo burst means being prerecorded with a predetermined servo burst magnetic flux transition pattern and having one longitudinal burst edge located substantially congruent with a track centerline of the said track, and having another longitudinal burst edge located substantially congruent with a track centerline of a second track immediately adjacent to said track, and second occurring servo burst means being prerecorded with the predetermined servo burst magnetic flux transition pattern for providing burst edges substantially congruent with track boundaries of the said track.
Claim 16
Dependent Claim
105 words
The servo sector pattern set forth in claim 15 further comprising third occurring servo burst means being prerecorded with the predetermined servo burst magnetic flux transition pattern and located spatially so that burst amplitude thereof is 180 degrees out of phase with the first occurring servo burst means such that the third occurring servo burst means has one circumferential burst edge located substantially congruent with the track centerline of said track and another circumferential burst edge located substantially congruent with a track centerline of a third track immediately adjacent to said track and wherein said track lies between said second track and said third track.
Claim 17
Dependent Claim
52 words
The servo sector pattern set forth in claim 15 wherein the track is a predetermined one of odd and even tracks and the second occurring servo burst means comprises a burst fully occupying the track and having its two longitudinal burst edges substantially congruent with the track boundaries of the said track.
Claim 18
Dependent Claim
66 words
The servo sector pattern set forth in claim 17 wherein the track is a predetermined other one of odd and even tracks and the second occurring servo burst means comprises two bursts fully occupying adjacent tracks of the predetermined ones of odd and even, and wherein adjacently facing longitudinal burst edges of the two bursts are substantially congruent with the track boundaries of the said track.
Claim 19
Dependent Claim
235 words
A high performance disk drive having a head position servo loop for positioning a data transducer head relative to a rotating data storage disk having at least one data storage surface including a prerecorded pattern of embedded servo sectors, the servo sector pattern prerecorded for each track being radially wider than the radial head gap width of the data transducer head, the pattern including for a second concentric data track lying between a first track and a third track of a multiplicity thereof: a servo sector address mark field including a magnetic flux transition pattern prerecorded therein for identifying the start of the servo sector pattern; a track number field including a magnetic flux transition pattern prerecorded therein for identifying the second data track from among the multiplicity thereof; a first occurring servo burst being prerecorded with a predetermined servo burst magnetic flux transition pattern and having one longitudinal burst edge located substantially congruent with a track centerline of the second track, and having another longitudinal burst edge located substantially congruent with a track centerline of the third track, and second occurring servo bursts being prerecorded with the predetermined servo burst magnetic flux transition pattern for providing burst edges substantially congruent with track boundaries of the second track relative to the first track and the third track, the second servo bursts being recorded entirely within the boundaries of the first track and the third track.
Claim 20
Dependent Claim
93 words
The disk drive set forth in claim 19 wherein the sector pattern further comprises for track following servo mode a third occurring servo burst being prerecorded with the predetermined servo burst magnetic flux transition pattern and located spatially so that its amplitude is 180 degrees out of phase with the first occurring servo burst such that the third occurring servo burst has one longitudinal burst edge located substantially congruent with the track centerline of the second track and another longitudinal burst edge located substantially congruent with a track centerline of the first track.
Claim 21
Dependent Claim
140 words
The disk drive set forth in claim 19 wherein the disk drive has a plurality of data zones of data tracks in which the data tracks thereof have predetermined data sector lengths and numbers and data transfer rates so as to render more optimal storage bit density and relative movement between the head and disk surface, each servo sector being radially aligned throughout the extent of the data zones, and each servo sector including a servo sync field preceding the servo address mark field for synchronizing a read channel means of the disk drive to the data rate of servo information included in the servo sector, and each servo sector being followed by a data sync field for resynchronizing the read channel means to the data rate of a particular data zone over which the data transducer head is passing.
Claim 22
Dependent Claim
45 words
The disk drive set forth in claim 21 including a frequency-programmable frequency synthesizer means operating under control of a programmed microcontroller means for programmably generating a plurality of coded frequencies for enabling the plurality of the data zones to operate at differing data transfer rates.
Claim 23
Dependent Claim
68 words
The disk drive set forth in claim 21 wherein a read channel includes a master state machine means responsive to each servo sync field in order to set up the read channel to read the address mark field and the track number field, and further responsive to the data sync field in order to set up the read channel to read the data field following each servo sector.
Claim 24
Independent Claim
229 words
A method for determining a digital radial head position value within a disk drive including a rotating storage disk defining a data storage surface, a data transducer head for reading and writing data from and to concentric data storage tracks on the storage surface, control electronics associated with the data transducer head and an actuator for moving the head and wherein each data track includes embedded sector servo information including a prerecorded track number and portions of a plurality of servo bursts, the method comprising the steps of: reading with the data transducer head the prerecorded track number from a track number field of a said embedded sector to determine radial head vicinity in relation to a said data track identified by the track number, determining the amplitude of a first servo burst in the vicinity of the said data track identified by the track number, determining whether the amplitude indicates that the head is over a burst edge, and if so, quantizing the amplitude read from the selected burst edge as a digital value, calculating a fine position vernier value relative to the said data track based upon the quantized digital value of selected burst edge amplitude, and adjusting the value of the track number by reference to the fine position vernier value thereby to provide the digital radial head position value for the said track and sector.
Claim 25
Dependent Claim
157 words
The method set forth in claim 24 wherein each of the plurality of servo bursts has a width greater than the width of a recording gap of the data transducer head, and wherein the data transducer head is radially positionable within a dead zone with respect to a said servo bursts, the servo bursts being arranged so that linear edges are aligned with dead zones, the method comprising the further steps of: determining whether the amplitude of the first servo burst indicates that the head is over a dead zone associated with the first servo burst and thereupon switching to and determining the amplitude of a second servo burst having an edge at least coextensive with the dead zone of the first burst, and quantizing the amplitude of the second servo burst, and calculating the fine position vernier value relative to the said data track based upon the quantized value of the second servo burst edge amplitude.
Claim 26
Dependent Claim
194 words
The method set forth in claim 24 wherein the embedded sector servo information includes a pattern prerecorded for the data surface and including for a second concentric data track lying between a first track and a third track of a multiplicity thereof: a servo sector address mark field including a magnetic flux transition pattern prerecorded therein for identifying the start of the servo sector pattern; a track number field including a magnetic flux transition pattern prerecorded therein for identifying the second data track from among the multiplicity thereof; a first occurring servo burst being prerecorded with a predetermined servo burst magnetic flux transition pattern and having one longitudinal burst edge located substantially congruent with a track centerline of the second track, and having another longitudinal burst edge located substantially congruent with a track centerline of the third track, and second occurring servo bursts being prerecorded with the predetermined servo burst magnetic flux transition pattern for providing burst edges substantially congruent with track boundaries of the second track relative to the first track and the third track, the second servo bursts being recorded entirely within the boundaries of the first track and the third track.
Claim 27
Dependent Claim
51 words
The method set forth in claim 26 comprising the further step of performing a recalibration operation to determine a high amplitude equivalence value and a low amplitude equivalence value for the first and second servo bursts, and calculating a slope value for the edges of the first and second servo bursts.
Claim 28
Dependent Claim
54 words
The method set forth in claim 24 comprising the further step of determining during a seeking operational mode the number of tracks crossed between successive samples of embedded sectors, and limiting the steps of quantizing burst edge amplitude and calculating a fine position vernier value to a track crossing rate below a predetermined value.
Claim 29
Dependent Claim
22 words
The method set forth in claim 28 wherein the predetermined value is a track crossing rate of five tracks per servo sample.
Claim 30
Dependent Claim
143 words
The method set forth in claim 26 wherein the disk drive has a plurality of zones of data tracks in which the data tracks thereof have predetermined data sector lengths and numbers and data transfer rates so as to render more optimal storage bit density and relative movement between the head and disk surface, each servo sector being radially aligned throughout the extent of the data zones, and each servo sector including a servo sync field preceding the servo address mark field for synchronizing a master state machine means for controlling a read channel of the disk drive to the data rate of servo information included in the servo sector, and each servo sector being followed by a data sync field for resynchronizing the read channel to the data rate of a particular data zone over which the data transducer head is passing.
Claim 31
Dependent Claim
17 words
The method set forth in claim 30 wherein the disk drive includes eight zones of data tracks.
References Cited (Backward Citations)
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