Shared memory access and data structure access control
CA 2057446 C · Owner: Bell-Northern Research Ltd. · Inventors: Baker, Brian Neil
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method and circuit for granting access to a block of memory in a multiprocessor system having a shared memory is provided. When a memory request for exclusive access to a block of memory is granted, the starting address for that block of memory is placed in a register bank, thereby opening a semaphore. The starting address of a memory block of a subsequent memory access request is compared with the starting addresses corresponding to open semaphores within the register bank and access is denied to the requested block of memory if a match is found. The starting address associated with a request which is denied access is placed in a temporary buffer and the request is later granted access …
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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 December 11, 1991 and granted February 17, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 11, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 11, 2013.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.