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Microsoft Year 2000 Readiness Disclosure & Resource Center |
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Windows Operating System Interactions with BIOS and Real Time Clock |
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6. Common Rollover Errors
Case 1
The century rollover code is missing from the BIOS program and the RTC century register is not updated.
During POST, the BIOS may not map invalid dates like 1900 to 2000. For example, if the PC was turned off during the transition from the year 1999 to 2000, the century register will still be set to "19" (1900) when the machine is turned on.
Case 2
The BIOS only allows years within a specific range.
During POST, the BIOS may not allow certain valid date ranges. For example, one commonly-used BIOS chip allows the years 1994 – 1999 and 2094 – 2099, but does not allow the years 1980 – 1993 or 2000 – 2093.
Case 3
BIOS Setup does not recognize dates after December 31, 1999.
When running BIOS Setup, a date of 1/1/2000 or greater may not be accepted.
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Features
