[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: [Fwd: Re: Y2K and Chicken Little]

> >It was my understanding that the RTC's made prior to 
> >about 2 years ago were suspect, which is the reason that 
> >they recommend turning off your computer when you check for 
> >Y2K compatability.
>     I did a lot experimenting with various old PS/2-machines. None of
> them is "Y2K-Ready" .......
>     You can try that at home: just for fun set the date to December
> 31st, 1999 and set the time to 23:59 maybe. Then go off to have a
> coffee or just sit around and wait. After some minutes type DATE again.
> (If you have Win95 and try this in a DOS-box it might happen that the
> system comes up with a message to check the clock - since it has been
> reset from "summertime zone values" ...)
>     Check the DATE again: it is 01.01.2000 then ... funny, eh ? Yes -
> *but* - if you power the machine down and power it up after some
> minutes the date is 04.01.1980 !!
>     Why ? Because the BIOS-developers forgot to write the updated
> Century-Byte into the CMOS when the Year-2000 rollover occures. The RTC
> is just a counter - after 1999 it counts one up and gets 2000. But the
> CMOS doesn't know - and the BIOS doesn't tell. But as we have learned
> further above: the system *can* handle the date. So now we enter the
> correct date again (01.01.2000 maybe) and switch the machine off again
> ... And after powering it up again the date is still 01.01.2000.
>     This behaviour is called "Level 2 compliance". It can handle the
> Y2K rollover in the software, the dates after 2000 can be stored and
> retrieved properly - but the BIOS doesn't do the century update in the
> CMOS automatically. It still requires *One* User interaction.
Interesting.  Did all the above with my old 486, and sure 
enough the second time around it remembered the 2K.  I was 
expecting to have to do it twice on the way back, but it 
took it on the first try going back to 1998. Not sure I 
understand why it takes 2 changes one direction and only 1 
to do the reverse. Anyway, tnx for info.

| Bill Jones, N3JLQ,Sweden, Maine  Zone 4 1/2  |
| wejones@megalink.net                         |
| http://www.megalink.net/~wejones             |
Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org