Century Rollover and Acpi S0-S5 states

It is possible to find some clear understanding of Century Rollover  issues  looking at recent  PC chip-sets specifications made by Intel .

Modern chip-sets like  those of Intel 6 Series ( see specs )  sets a  special bit when a transition from year 99 to 00 occurs. That generates an SMI  ( a special code managed  by Bios firmware  ) when the machine is in S0  state.

S0 state  means  that machine is fully operational : in this case  firmware code can react immediately and update the century byte ( Smi handler  should be executed before any similar operation programmed by the running Operating system .I think that  a possible conflict in this sense has to be fully verified by QA).

It could be that machine is in a different power state during transition from  year 99 to year 00 :machine could be in standby or in power off or in hibernation .In this case  firmware code should correct the   Century byte  as soon  CPU   will restart normal execution .

Using this approach based on Intel recomandations , transition to new century will proceed smootly and without specific issues in all power states.

Vincenzo Ianieri   molise@molise.com

 

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Welcome !

Welcome to Year2100 computer bug web site. My purpose is to track any evolution in the analisys and fix of this  bug that is similar to the more famous Y2k  or millenium bug.

You can find how to reproduce here .

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