IBM-AUSTRIA - PC-HW-Support    30 Aug 1999

BIOS 27A AND 28A could CORRUPT SYSTEM TIME AND DATE

    Record number:       H015613
    Device:              D/T8640
    Model:               M
    Hit count:           UHC00010
    Success count:       USC0000
    Publication code:    PC50
    Tip key:
    Date created:        O98/12/23
    Date last altered:   A99/02/09
    Owning B.U.:         USA


Abstract: BIOS 27A AND 28A could CORRUPT SYSTEM TIME AND DATE

SYMPTOM:

System experiencing invalid time and date regardless the year.

PROBLEM ISOLATION AIDS:

•  The system is one of the following IBM PC Servers:

    a PC Server 320, Type 8640, any PCI/Micro Channel Model.
    a PC Server 520, Type 8641, any PCI/Micro Channel Model.

•  The system is configured with 1 or 2 Processors.
•  The system's BIOS levels affected are: 27A and 28A
•  The system's Diagnostics Pass.

FIX:

Download and apply the latest BIOS for the Planar from the following URL:

http://www.pc.ibm.com/searchfiles.html

Search on either "PC Server 320 BIOS" or "PC Server 520 BIOS"

Validate the fix immediately after the new BIOS update is complete.
Simply set the system time to 19:00 and reboot the system within 1 minute, then re-check the time.

WORKAROUND:

Make sure BIOS 1A, Read Real Time Clock call (AH=2) is not used in the time period from 19:00 to 19:05, inclusively. Including power on or reboot the machine to load Operating System.

DETAILS:

BIOS could corrupt the Real Time Clock's time and date registers if the following event occur:

1.  System reboot in the time period between 19:00 and 19:05,
    and the Read Real Time Clock BIOS call is executed.

     -- OR --

2.  Any time a Read Real Time Clock BIOS call is used between 19:00 and 19:05,
    by software, such as operating system, device driver or applications.

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