Doc. # 1-0000301
Date Updated 02-03-2005 Date Created 07-27-2000
Document Type Knowledge Base Related OS
Related Product
Concerns about YEAR2000 compliance.
Solution:
There are three system times in a computer system ?DOS time, BIOS time and RTC(CMOS) time. For example, under DOS environment, we can access the three system times by using: DOS interrupt 0x21, 0x2A/0x2C BIOS interrupt 0x1A, 0x04/0x02 RTC(CMOS) direct port addressing The RTC time (19xx) is stored in address 32H(the century : thousand digit and hundred digit) and 09H (the year held). For example, the year 1998 is stored as 32H=19 and 09H=98. The most important point is - only the 09H is controlled by RTC, so the time in the 09H will auto-count, but the time in the 32H has to be modified by BIOS or programs. When the AT class PCs were designed, this issue was neglected by computer manufacturers, and it causes the year 2000 crisis. In order to correct this problem, our BIOS updates the time (32H) by the following 4 ways : (1) While executing ate?command in the DOS. (2) The system is rebooted. (3) When executing BIOS setup. (4) When the INT 1AH BIOS call is executed. So far, the above 4 ways are widely used by all of computer/BIOS manufacturers. However, during the transition from 1999-12-31 to 2000-01-01, if an application doesn use any of above conditions and gets the RTC time by using direct port addressing. It is possible that the application will get a wrong time - ? 1900-01-01? To prevent from getting the wrong system time on our products, we provide some ways for this situation: (1) If your applications can be turned off direct port addressing during the transition from 1999-12-31 to 2000-01-01. Please shut it down, and turn it on after the transition time. (2) Don't use direct port addressing to get the RTC time in applications. (3) If your applications use direct port addressing to get the CMOS, but, fortunately, the OS is of DOS, Windows 95 or OS/2. You can run the program ear2000.com? a TSR program which is provided by Award, to resolve it. This program will monitor the CMOS time at