Method and means for switching system control of cpus
CA 1182575 A · Owner: International Business Machines Corporation · Inventors: Gum, Peter H.; Bean, George H.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The embodiment switches an address in a prefix register in a CPU of a MP or UP data processing system from one PSA (program save area) to another PSA. The prefix address switching changes the control of the CPU from a preferred guest SCP (system control program) to a host SCP. This switching is done by hardware/ microcode means which is not controllable by user instructions executable on the CPU. This manner of CPU control switching obtains for a preferred guest SCP (such as MVS/370) operating in relation to a host SCP (such as VM/370) nearly the efficiency of standalone execution on the CPU by a preferred guest SCP that is the same as a standalone version of the guest SCP.
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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 February 12, 1985. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended February 12, 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.
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.