Disk level servo write

  • US 6,611,396 B1
  • Filed: 04/24/2000
  • Issued: 08/26/2003
  • Est. Priority Date: 04/24/2000
  • Status: Expired due to Fees
First Claim
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1. A method for assembling and operating a fixed media hard disk drive using disks on which servo information is pre-written while off the drive spindle of said hard disk drive, which disks are subsequently mounted on said drive spindle and on which are then defined a set of rotationally concentric “

  • virtual tracks”

    for seeking and following in terms of said pre-written servo tracks comprising;

    providing a fixed media hard disk;

    mounting said disk in a servo track writing assembly dedicated to the writing of servo tracks;

    writing said servo tracks on said disk;

    transferring said servo-written disk to a disk drive assembly comprising a spindle, a read/write head, a head actuator assembly, and a runout compensator;

    mounting said disk on said spindle of said drive assembly;

    closing said disk drive assembly and mounting it on a PCB;

    testing said disk drive assembly;

    defining, during said testing process, a set of virtual tracks on said disk in terms of intersections between said pre-written servo tracks and circular paths of said read/write head, said intersections being obtained by means of a process comprising;

    choosing a set of n different radial positions on said disk;

    locking onto the written servo track at one of said radial positions;

    turning on the runout compensator;

    obtaining a position error signal with runout compensation included as a sum of harmonics multiplied by harmonic coefficients k1 and k2;

    choosing a transition rate, ε

    , to provide a smooth and stable transition from the physical track domain to the virtual track domain;

    recording harmonic coefficients k1 and k2;

    defining the position error signal for the virtual track in the virtual track domain;

    repeating the previous six steps for each of the remaining radial positions;

    creating a table in which all other virtual tracks are defined;

    storing said table as a non-volatile memory array;

    transitioning the disk drive to the virtual domain.

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