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Expired Canadian patentCanada

Apparatus for reducing interrupt retry attempts

CA 2080956 C · Owner: Keeley, James W. · Inventors: Barlow, George J.; Keeley, James W.

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

A multiprocessor computer system having a first processor having a first interrupt mechanism for generating interrupt requests a second processor, having a second interrupt mechanism and a system bus for communicating, interrupt requests from the first processor to the second processor. The second interrupt mechanism is responsive to an interrupt request by generating an acknowledge response on the system bus when the second processor accepts the interrupt request and generating a not acknowledge response on the system bus when the second processor contains a previous and pending interrupt request of higher level and refuses the interrupt request. The second interrupt mechanism is …

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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

  • Filed October 20, 1992 and granted August 19, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 20, 2012.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 20, 2014.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledOctober 20, 1992
GrantedAugust 19, 1997
Term endedOctober 20, 2012
Patent numberCA 2080956 C
Classification (IPC)G06F13/37 +2 more

Timeline

Timeline From CIPO dates

1993199519971999200120032005200720092011Application filedOct 20, 1992Patent grantedAug 19, 1997Term endedOct 20, 2012

Sources & verification

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