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US4485418A Expired / Lapsed US ⏱️ 0.0 years remaining

System and method of locating the center of a track on a magnetic storage disk

Assignee: Seagate Technology LLC
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Filing: 1982-08-12
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Granted: 1984-11-27
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Expires: 2002-08-12
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Abstract

Abstract A system and method of accurately locating the center of a previously recorded magnetic track on a rotating magnetic storage disk and moving a transducer to the center of the track. The system measures in increments the amplitude of the feedback signal as the transducer is moved to each side of the recorded track and compares the signal amplitude measured with a predetermined reference level. Through the use of an offset measuring system connected to a computer processor the number of increments moved in each direction is recorded and a simple calculation is made to determine the center of the magnetic track. The transducer for recording and replaying information on the disk is then moved to the center of the track.

Inventors

  • 👤 Robert A. Bremmer

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-24 18:47
CPC Classifications
G; G11; G11B; G11B21/00; G11B21/02; G11B21/10; G11B21/106; G11B5/00; G11B5/48; G11B5/58; G11B5/596; G11B5/59627

Claims Analysis

Total Claims: 9
Claim 1
Independent Claim 144 words
A system for accurately locating the center of a previously recorded magnetic track on a rotating magnetic storage disk, the system measuring in increments across the track width a signal amplitude of the track above and below a predetermined reference level, the system comprising: a transducer for recording and replaying signal information from the disk; a motor attached to the transducer for moving the transducer over a nominal position of the track and moving the transducer in increments across the track width; a computer processor having memory storage therein and connected to the motor, the processor upon receiving a calibration command causing the motor to move the transducer in small increments across the track width; an offset measuring system connected to the transducer and the processor for determining if the signal amplitude is greater or less than the reference level after each increment movement.
Claim 2
Independent Claim 144 words
A system for accurately locating the center of a previously recorded magnetic track on a rotating magnetic storage disk, the system measuring in increments across the track width a signal amplitude of the track above and below a predetermined reference level, the system comprising: a transducer for recording and replaying signal information from the disk; a motor attached to the transducer for moving the transducer over a nominal position of the track and moving the transducer in increments across the track width; a computer processor having memory storage therein and connected to the motor, the processor upon receiving a calibration command causing the motor to move the transducer in small increments across the track width; an offset measuring system connected to the transducer and the processor for determining if the signal amplitude is greater or less than the reference level after each increment movement.
Claim 3
Dependent Claim 20 words
The system as described in claim 1 wherein the calibration command to the processor is generated by a host system.
Claim 4
Dependent Claim 21 words
The system as described in claim 1 wherein the calibration command to the processor is generated by a unit power-on sequence.
Claim 5
Dependent Claim 73 words
The system as described in claim 1 wherein the offset measuring system includes a peak level detector for receiving the signal amplitude from the transducer and a comparator circuit connected to the peak level detector, the comparator circuit comparing the signal amplitude to the predetermined reference level, the comparator connected also to the processor for signaling the processor when the signal amplitude received is of a value above or below the reference level.
Claim 6
Independent Claim 188 words
A system for accurately locating the center of a previously recorded magnetic track on a rotating magnetic storage disk, the system measuring in increments across the track width a signal amplitude of the track above and below a predetermined reference level, the system comprising: a transducer for recording and replaying signal information from the disk; a motor attached to the transducer for moving the transducer over a nominal position of the track and moving the transducer in increments across the track width; a computer processor having a memory storage therein and connected to the motor, the processor upon receiving a calibration command causing the motor to move the transducer in small increments across the track width; and an offset measuring system connected to the transducer and the processor, the offset measuring system having a peak level detector for receiving the signal amplitude, the peak level detector connected to a comparator circuit, the comparator circuit comparing the signal amplitude to the predetermined reference level, the comparator connected to the processor for signaling the processor when the signal amplitude received is of a value above or below the reference level.
Claim 7
Independent Claim 188 words
A system for accurately locating the center of a previously recorded magnetic track on a rotating magnetic storage disk, the system measuring in increments across the track width a signal amplitude of the track above and below a predetermined reference level, the system comprising: a transducer for recording and replaying signal information from the disk; a motor attached to the transducer for moving the transducer over a nominal position of the track and moving the transducer in increments across the track width; a computer processor having a memory storage therein and connected to the motor, the processor upon receiving a calibration command causing the motor to move the transducer in small increments across the track width; and an offset measuring system connected to the transducer and the processor, the offset measuring system having a peak level detector for receiving the signal amplitude, the peak level detector connected to a comparator circuit, the comparator circuit comparing the signal amplitude to the predetermined reference level, the comparator connected to the processor for signaling the processor when the signal amplitude received is of a value above or below the reference level.
Claim 8
Independent Claim 274 words
A method for accurately locating the center of a previously recorded magnetic track on a rotating magnetic storage disk, the system measuring in increments the signal amplitude of the track as a signal detecting transducer is moved incrementally and compares the detected signal with a predetermined reference level, the steps including: sending a calibration command to a computer processor having memory storage therein, the processor connected to a motor for driving a transducer over the disk for recording and replaying signal information on the disk; moving a transducer across a fraction of the track through motor action; receiving a signal amplitude of the track by an offset measuring system, the offset measuring system connected to the transducer and the processor, the offset measuring system determining if the signal amplitude is greater or less than the reference level; signaling the processor to have the motor move the transducer in increments toward one side of the track until the signal amplitude becomes less than the reference level; signaling the processor to have the motor move the transducer to the original nominal position and then move in increments to the opposite side of the track until the signal amplitude becomes less than the reference level; signaling the processor to have the motor move the transducer to its original nominal position and then move a calculated number of increments either toward one side of the track or toward the opposite side of the track based on the number of increments moved to one side of the track less the number of increments moved to the opposite side of the track, this total number of increments divided by two.
Claim 9
Independent Claim 274 words
A method for accurately locating the center of a previously recorded magnetic track on a rotating magnetic storage disk, the system measuring in increments the signal amplitude of the track as a signal detecting transducer is moved incrementally and compares the detected signal with a predetermined reference level, the steps including: sending a calibration command to a computer processor having memory storage therein, the processor connected to a motor for driving a transducer over the disk for recording and replaying signal information on the disk; moving a transducer across a fraction of the track through motor action; receiving a signal amplitude of the track by an offset measuring system, the offset measuring system connected to the transducer and the processor, the offset measuring system determining if the signal amplitude is greater or less than the reference level; signaling the processor to have the motor move the transducer in increments toward one side of the track until the signal amplitude becomes less than the reference level; signaling the processor to have the motor move the transducer to the original nominal position and then move in increments to the opposite side of the track until the signal amplitude becomes less than the reference level; signaling the processor to have the motor move the transducer to its original nominal position and then move a calculated number of increments either toward one side of the track or toward the opposite side of the track based on the number of increments moved to one side of the track less the number of increments moved to the opposite side of the track, this total number of increments divided by two.

References Cited (Backward Citations)

US4157577A Cited
US4371960A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1987-11-27 1988-05-28 1988-11-27 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1991-11-27 1992-05-28 1992-11-27 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1995-11-27 1996-05-28 1996-11-27 $7700.00 Window Closed / Lapsed

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