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Expired Canadian patentCanada

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CA 1197021 A · Owner: International Business Machines Corporation · Inventors: Hartung, Michael H.; Nolta, Arthur H.; Reed, David G.

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

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Abstract From the Canadian patent

A so-called "roll mode" technique provides block transfer with a disk-type of direct-access data-storage device (DASD). A set of chained commands for accessing record areas enables rapidly accessing a plurality of records within a given DASD cylinder of tracks. The rotational position of the surfaces is checked. The command within the chain, irrespective of its location having the closest logical rotational proximity to the instant rotational position of the surfaces is selected as the first command in the chain. The chain is executed beginning at the indicated rotational position selected command through the end of the chain and then wrapped to the beginning of the original chain and …

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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 19, 1985. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended November 19, 2002.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledAugust 24, 1983
GrantedNovember 19, 1985
Term endedNovember 19, 2002
Patent numberCA 1197021 A
Classification (IPC)G06F12/00 +2 more

Timeline

Timeline From CIPO dates

1984198619881990199219941996199820002002Application filedAug 24, 1983Patent grantedNov 19, 1985Term endedNov 19, 2002

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