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Expired Canadian patentCanada

Servo gain compensation in a disc drive

CA 1324663 C · Owner: Hewlett-Packard Company · Inventors: Jackson, Bruce J.; Knowles, Vernon L.; Overton, Wallace H.

CIPO record

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

Compensation for servo gain variations when connected to different magnetic heads in a disc memory drive is achieved by determining individual servo gain corrections for each magnetic head at several different selected tracks on the associated memory disc, storing the individual servo gain corrections and addressing a stored individual servo gain correction for each selected magnetic head for coupling to the servo to equalize servo gain when positioning each selected magnetic head at a selected track.

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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.

Why it's free to use

  • Granted November 23, 1993. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended November 23, 2010.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledMay 12, 1987
GrantedNovember 23, 1993
Term endedNovember 23, 2010
Patent numberCA 1324663 C
Classification (IPC)G11B5/59 +1 more

Timeline

Timeline From CIPO dates

19881991199419972000200320062009Application filedMay 12, 1987Patent grantedNov 23, 1993Term endedNov 23, 2010

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.