RTC, BIOS, DOS, and Windows Clock Compliance: The RTC (Real Time Clock) is a device in your computer that maintains the time (measuring elapsed time) even when you turn off, or unplug your PC. Accurate time measure is needed, not only so you can use your PC as a timepiece. Your PC uses accurate time to perform a flow of computing tasks. The RTC clock gives your computer the ability to perform tasks in order.
The BIOS (Basic Input/Output System) clock is stored in firmware.When you start your computer, the BIOS reads the date and time from the RTC. The BIOS is your PC’s “traffic cop,” which dictates how software interacts with all the peripheral devices in your computer, including the RTC clock. Non-compliant BIOS clocks have reset themselves from 12/31/99 to 01/01/1900 when the year 2000 begins.
The DOS (Disk Operating System) clock gets its date and time from the BIOS clock, and then makes the current date and time available to you or to any application that requests it. You can change the DOS date and time in an MS-DOS Prompt window using the DATE or TIME commands. Non-compliant DOS clocks have reset themselves from 12/31/99 to 01/04/1980 (the date when DOS was originally released, and before which it did not need to support a current date).
The Windows clock gets its information from the
DOS clock, and makes the date and time available to Windows applications, or to
you via the Date/Time control panel. Non-compliant Windows clocks have also
reset themselves from 12/31/99 to 01/04/1980.
RTC Roll Over Failure ( Real Time Clock )
Failures on the RTC roll over test are quite common.
This is due to the current implementation of the real time clock, which
stores the century information, but does not automatically update the century
when the year rolls over from 99 to 00.
This problem may be corrected by the BIOS, in which case the problem has no effect. If the BIOS does not correct for this problem, it can be remedied by verifying or manually setting the date after the roll over to the year 2000.
If testing has indicated your BIOS corrects for the RTC problem, it is not necessary to take any corrective action.
However, as a precaution we recommend performing the following action during the transition from 1999 to 2000.
ˇ On December 31, 1999, switch off your computer sometime before midnight.
ˇ After the year has progressed from 1999 to 2000, power up the computer. The date should have correctly rolled over to January 1, 2000.
These materials have been
prepared by On-Site Computer Service for informational purposes only and are not
intended to be technical advice. Transmission and receipt of information
is not intended to create any relationship between the sender and receiver.
A reader should not act upon any information provided without first seeking
further technical consultation.
On-Site Computer ServiceŠ 1999