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公开(公告)号：SG67406A1
公开(公告)日：1999-09-21
申请号：SG1997002591
申请日：1995-11-10
Applicant: IBM
Inventor： CHAINER TIMOTHY JOSEPH , PRAINO ANTHONY PAUL , SCHULTZ MARK DELORMAN , WEBB BUCKNELL CHAPMAN , YARMCHUK EDWARD JOHN
Abstract: Improvements in placement of timing patterns in self servo writing include correcting for random and systematic errors due to geometric effects. In a disk drive having a recording head with separate read and write elements, a method for determining separation between the elements and for correcting for such errors as a function of skew angle between the head and the disk. Errors resulting from misalignment and non-parallelism of the elements as well as misalignment of the head on it its actuator are also detected and corrected. Errors due to changes in rotational velocity of the disk and misplacement of timing patterns with respect to adjacent timing patterns are detected and corrected. In general, a single revolution process may be used to both write and detect random errors on each track and corrected on subsequent tracks.
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公开(公告)号：DE69507579D1
公开(公告)日：1999-03-11
申请号：DE69507579
申请日：1995-11-23
Applicant: IBM
Inventor： YARMCHUK EDWARD JOHN , SCHULTZ MARK D , WEBB BUCKNELL C , CHAINER TIMOTHY JOSEPH
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公开(公告)号：DE3872438D1
公开(公告)日：1992-08-06
申请号：DE3872438
申请日：1988-04-21
Applicant: IBM
Inventor： DOVE DEREK BRIAN , KEEFE GEORGE EDWARD , YARMCHUK EDWARD JOHN
Abstract: A magnetographic printing head (26) comprises an array of crossed elongated bar-shaped print elements (58, 62) each of which is individually magnetizable by electrical conductors (40) wound about respective ones of the print elements (58, 62). The print elements (58, 62) are arranged in two parallel arrays which are spaced apart from each other to define a passage (24) through which a magnetic medium (22) is to be passed for the imprinting of marks (66) thereon. A mark (66) can be imprinted at each cross point (64) of the crossed arrays upon application of sufficient magnetizing current to each of the print elements (58, 62) at the cross point (64). The print elements (58, 62) are specifically shaped to provide for concentration of magnetic fields at the cross points (64) in two dimensions to accomplish high resolution printing. The concentration of the fields is accomplished in one embodiment of the invention by the use of a knife-edge (68) configuration to opposed facing surfaces of the elements of the opposed arrays, and in a second embodiment by a set of pedestals (72) upstanding from the elements of one of the arrays. The resulting configuration of the print head (26) has structural simplicity which permits economical fabrication while retaining high resolution in the printing.
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公开(公告)号：CA2365155C
公开(公告)日：2002-08-20
申请号：CA2365155
申请日：1995-11-24
Applicant: IBM
Abstract: A mechanism for servowriting on a storage medium of a storage device. The storage device has a transducer and a servo loop for positioning the transducer with respec t to the storage medium. At least one transition is written on a track of the storage medium, while servoing on other transitions previously recorded on the storage medium. A reference waveform is derived as a function of a closed loop response of the servo loop and a position error waveform. The position error waveform corresponds to one or more position errors of the transducer relative to the previously recorded transitions. The reference waveform is usable in writing subsequent tracks on the storage medium. Using the reference waveform for writing subsequent trac ks provides a substantial rejection of mechanical disturbances by the servo loop.
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公开(公告)号：CA2366415C
公开(公告)日：2002-07-16
申请号：CA2366415
申请日：1995-11-24
Applicant: IBM
Abstract: During a write revolution of a storage medium, a transition is written on th e storage medium while servoing on another transition previously recorded on the storage medium. During that write revolution, a position error signal corresponding to the position error of t he transducer relative to the previously recorded transition is determined. That position error signal is then stored, during the write revolution, to be used in computing a reference track value associated with the transition being written to correct for the position error. Additionally, a product servo- pattern is written, which includes an embodying of the position error therein.
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Patent Agency Ranking
公开(公告)号：CA2365103C
公开(公告)日：2002-07-16
申请号：CA2365103
申请日：1995-11-24
Applicant: IBM
Abstract: During a write revolution of a storage medium, a transition is written on th e storage medium while servoing on another transition previously recorded on the storage medium. During that write revolution, a position error signal corresponding to the position error of t he transducer relative to the previously recorded transition is determined. That position error signal is then stored, during the write revolution, to be used in computing a reference track value associated with the transition being written to correct for the position error. Additionally, a product servo- pattern is written, which includes an embodying of the position error therein.
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公开(公告)号：SG64425A1
公开(公告)日：1999-04-27
申请号：SG1997002067
申请日：1997-06-16
Applicant: IBM
Inventor： CHAINER TIMOTHY JOSEPH , SCHUTLZ MARK DELORMAN , WEBB BUCKNELL CHAPMAN , YARMCHUK EDWARD JOHN
Abstract: A self-servowriting system and method for implementation in a storage device such as a disk drive are described. Two problems associated with self-propagation are greater mechanical disturbances and the growth of errors during many thousands of servowriting steps. Error growth is attributable to the special properties of servo loops as applied to a repetitive self-propagation process. Greater resistance to mechanical disturbances and reduction in error growth are achieved, in part, by adjusting a step amplification factor, S, at the initiation of servowriting to within desired parameters. However, S is known to vary with movement of the head in a direction transverse to the direction of the tracks. This problem is addressed by the present invention, wherein S is determined at a plurality of transverse transducer positions. S is dependent upon the closed loop response of the servo system C and upon a set of step-to-step correction factors f. S is therefore determined by monitoring an indicium of S such as C, and is adjusted by adjusting either C or f to provide a value of S which falls within an acceptable range of values. Determination of S is scheduled to occur at predefined intervals. The intervals may be fixed or adjusted adaptively based upon the measured variation of S with transducer position.
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公开(公告)号：HUT77922A
公开(公告)日：1998-10-28
申请号：HU9801391
申请日：1995-03-13
Applicant: IBM
Inventor： CHAINER TIMOTHY JOSEPH , SOHN WAYNE JAY , YARMCHUK EDWARD JOHN
IPC: G11B5/596
Abstract: The method comprises the steps of generating a timing pattern on the storage medium with a recording head internal to the recording device, and determining a radial positioning value for at least one of radial regions from a pattern propagated by the internal recording head in the region. - The radial positioning value is used for positioning the internal recording head. A servo-pattern is recorded on the storage medium by the head, at locations determined by the timing pattern and the radial positioning value. - (Dwg.1a/18)
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公开(公告)号：SG52937A1
公开(公告)日：1998-09-28
申请号：SG1997000894
申请日：1997-03-22
Applicant: IBM
Inventor： CHAINER TIMOTHY JOSEPH , SCHULTZ MARK DELORMAN , WEBB BUCKNELL CHAPMAN , YARMCHUK EDWARD JOHN
Abstract: Methods and systems for self-servowriting a data storage medium are disclosed, including servoing to propagation bursts of a propagation pattern located in tracks other than an immediately preceding track. Reference levels used to position a recording head are accordingly kept in a usable dynamic range necessary to keep servo track spacing constant across the medium. The methods and systems are disclosed in connection with a rotary actuator having spaced read and write heads. Similar methods are disclosed for writing trigger or timing bursts of the propagation pattern.
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公开(公告)号：SG50848A1
公开(公告)日：1998-07-20
申请号：SG1997002060
申请日：1997-06-14
Applicant: IBM
Inventor： CHAINER TIMOTHY JOSEPH , SCHULTZ MARK DELORMAN , WEBB BUCKNELL CHAPMAN , YARMCHUK EDWARD JOHN
Abstract: An accurate and time-efficient method and system for self-servowriting wherein at least one reference value used to position the transducer is updated for some, but not all, of the tracks to be written. The reference value(s) is dependent upon a predefined indicium of transducer position, such as the amplitude of the readback signal obtained from a written track when the transducer is positioned on the track. In a first embodiment, updating of the reference value(s) is performed at every Nth track written, where N is a fixed number or range of numbers determined by an expected track-to-track variation of the indicium. The servowriting system may be designed to dynamically increase or decrease N during servowriting in response to actual variations in the indicium. According to a second embodiment, updating is only performed when needed, e.g. when the variation of the measured indicium between two written tracks (not necessarily adjacent tracks) exceeds a predefined threshold value. For systems employing dual-element heads, servowriting accuracy is enhanced by performing a read head adjustment prior to updating of the reference values.
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