Dual bus microcomputer system with programmable control of lock function
CA 2016400 C · Owner: International Business Machines Corporation · Inventors: Begun, Ralph M.; Bland, Patrick M.; Milling, Philip E.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A dual bus microcomputer system including a cache subsystem improves performance under certain circumstances by allowing programmable control over the LOCK function. More particularly additional logic is coupled between the LOCK output of the CPU and the LOCK input of the cache controller. A control bit from an I/O port is a second input to the additional logic. With the control bit in one state, the logic allows the LOCK input to follow the LOCK output. In the other state of the control bit the LOCK input is disabled regardless of the state of the LOCK output.
Read the whole patent
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 May 9, 1990 and granted January 2, 1996. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 9, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 9, 2012.
- 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.