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公开(公告)号：SG82615A1
公开(公告)日：2001-08-21
申请号：SG1999002731
申请日：1999-05-24
Applicant: IBM
Inventor： SERRANO LOUIS JOSEPH , YU MANTLE MAN-HON , BLAUM MARIO , KABELAC WILLIAM JOHN
Abstract: There is disclosed an error correction and detection method and apparatus for retreiving predetermined data, e.g. servo data, from the position error signal (PES) fields of a disk in a data storage system . In the preferred embodiment the PES data such as the track number is mapped into codewords of an error correction code (ECC) which are then further divided into a set of symbols which are mapped onto a second set of bit vectors which have a constant weight. The preferred encoding method is selected to equalize the analog signal characteristics of the PES fields so that minimal, if any, change in the conventional servo detection circuitry needed to use the PES fields of the invention both as analog and digital information.
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Patent Agency Ranking
公开(公告)号：DE10020092A1
公开(公告)日：2001-03-01
申请号：DE10020092
申请日：2000-04-22
Applicant: IBM
Inventor： DOBBEK JEFFREY JOSEPH , ROWAN BRYAN SCOTT , SERRANO LOUIS JOSEPH , YU MANTIE MAN-HON
Abstract: Method and system aspects for controlling spindle motor speed during head loading in a disk drive are described. The aspects include inputting a time-varying reference velocity profile signal, and selecting a controller to control spindle motor speed. Further included is feeding forward control signals sufficient to precompensate for drag during a head loading event and maintain spindle motor speed within an operating tolerance.
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公开(公告)号：SG60182A1
公开(公告)日：1999-02-22
申请号：SG1998000065
申请日：1998-01-08
Applicant: IBM
Inventor： SERRANO LOUIS JOSEPH , YU MANTLE MAN-HON
Abstract: In a hard disk drive, a head actuator periodically is caused to undertake a calibration seek such that the power amplifier that energizes the head actuator is saturated. The predicted distance moved by the head during the calibration seek is compared to the actual distance moved, and the ratio of the two distances is then used to determine the saturation current of the power amplifier. For a subsequent seek, if the saturation current is less than the current requested for the subsequent seek, the saturation current is input into the head position prediction model. Otherwise, the requested current is used.
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公开(公告)号：SG76621A1
公开(公告)日：2000-11-21
申请号：SG1999002740
申请日：1999-06-01
Applicant: IBM
Inventor： SERRANO LOUIS JOSEPH , YU MAN-HON MANTLE , BLAUM MARIO , KABELAC WILLIAM JOHN
Abstract: There is disclosed a disk for use in a disk drive and a method for making the disk. The position error signal (PES) fields for each track on the disk are written with predetermined data, e.g. servo data, encoded thereon. In the preferred embodiment: a) the data such as the track number is mapped into codewords of an error correction code (ECC); b) bit-vectors are used to encode the symbols for further redundancy; and c) the raw data written in the PES fields is constrained to equalize the analog signal characteristic used by the servo system for positioning. Thus, the invention allows the PES fields to be used as in the prior art while also being used as a source of digital data which is robustly recorded therein. In one aspect of the invention, the track ID's are written in the PES fields in a selected pattern in which the track ID for each track is recorded in two PES field groups. One of the two PES field groups is centered on the selected track while the other PES field group is offset so that it partially overlaps the adjacent track, as well as the selected track. The PES fields will typically be recorded on the disk at the time of manufacture and not changed thereafter.
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公开(公告)号：SG64475A1
公开(公告)日：1999-04-27
申请号：SG1998000379
申请日：1998-02-20
Applicant: IBM
Inventor： SERRANO LOUIS JOSEPH , YU MANTLE MAN-HON
Abstract: A method and apparatus for writing binary servo data into the servo bursts contained on the storage medium of a storage device. The binary servo information may include track identifying information such as a track number, cylinder number, head number, sector number, index and/or SID. A burst includes T time slots, each slot comprising one cycle of the servo burst frequency, and the servo data to be written comprises X bits of binary data. Each one-bit of the servo data is represented as a slot containing a transition, and each zero-bit is represented as an empty or null slot. In this manner, the present invention provides a highly bit-efficient scheme for representing digital servo data. A high quality PES signal is assured by writing the binary servo information in such a manner as to guarantee a threshold number of transitions per burst as required for accurate peak-hold detection. Data is encoded to provide a constant or substantially constant number of positive transitions per burst to allow accurate integration detection. If the amount of real estate consumed by the servo regions is less critical than the reliability of the binary data, robustness may be enhanced by using dibits rather than single transitions to represent the data.
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公开(公告)号：SG54561A1
公开(公告)日：1998-11-16
申请号：SG1997003261
申请日：1997-09-08
Applicant: IBM
Inventor： ROWAN BRYAN S , SERRANO LOUIS JOSEPH
IPC: G11B5/55 , G11B21/08 , G11B33/10 , G11B15/473
Abstract: A system and method for determining the velocity and/or position of a coil driven actuator arm without the aid of servo signals. A sample-hold unit is used to measure no-motion coil voltage in the voice motor coil while applying a predetermined coil current. Then, while the same magnitude (opposite direction) current is applied to move the actuator arm, the coil voltage is measured. The coil voltage is reduced by the measured no-motion coil voltage, producing a measurement of back-emf. The back-emf may be amplified by a predetermined factor to yield an estimation of velocity, and this amount may be integrated to provide a gauge of relative actuator arm position.
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