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


On Sun, 2 Aug 1998 11:31:50 -0400, Bill Jones wrote:

>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.

The following was excerpted from the Microchannel Enthusiast's web site
(http://members.aol.com/mcapage0/mcaindex.htm), and may shed some light
on the hardware side of Y2K:

With the introduction of the PC-AT machines IBM has the CMOS to store
configuration information and parts of the date and a Real Time Clock
(RTC). Both are battery-backed to continously track the actual date and
time - even with the computer switched off. At CMOS memory position 37h
we can find the so-called "Century Byte", which is the BCD-value "19"
    The PC and XT missed the CMOS - and the entire Real Time Clock
(RTC) at all. They use a "Timing Counter" instead, which has to be set
manually at each startup or from an external RTC on a Multi-Function
card for example.

    Let's examine the Century Byte a bit closer. To proove that this is
no "dummy variable" do the following:

    - Start DEBUG at the DOS-prompt
    - type o 70 37 (adresses byte 37h of the CMOS via I/O-port 70h)
    - type i 71 (reads the byte from 37h via I/O-port 71h)
    - (Output Value appears...)
    - type q to Quit DEBUG

    and you will get "19" as output value. Now change the machine date
using DATE at the DOS-prompt into anything after 2000 and repeat the
above procedure. Surprise, surprise: the output value is "20" now.
Don't forget to reset the date to the actual values ...

    So what's the fuss about Y2K then anyway ?
    Could it be ignored ?

    Well - one might ignore it. If you are not in a business and use
your PS/2 for home purposes only - the problems won't touch you much
anyways. But it is always good to know what's going on there.

    I did a lot experimenting with various old PS/2-machines. None of
them is "Y2K-Ready" - as largely announced by various manufacturers of
computer-equipment (even Printers, CD-ROMs and Monitors are claimed as
"Y2K-Ready" in the ads ...).
    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.

    What must we do ? Any recommendations ?

    Assumed you run your PS/2 under any Windows or OS/2 and it is
January 1st 2000. Just open a DOS-box and type DATE. If you had just
switched on your machine you will find a date of 04-01-1980 since the
"Timing Counter" in the RTC had rolled over in a new year - but the
Century Byte in the CMOS is still 19 ...!
    You might ask: "Why isn't it 01.01.1900 then ?"
    It isn't since the BIOS assumes that an RTC-counter value of all
zeros is January 4th 1980 -  the earliest date an IBM PC BIOS knows -
maybe it was the date an IBM PC was running with a pre-release DOS 1.0
Version ... belongs in the chapter "Odd and funny history" as well.
    That's the default date you see after your CMOS battery had died
and all RTC- and DOS timer counters are reset to zero.
    Okay - since the date is 01-04-1980 after the first power up in
year 2000 just type in the actual date 01-01-2000 and press Enter.

    If you had your system running, because it is a server or you
worked the whole night over from December 31st to January 1st - the
displayed DATE is 01-01-2000 already. Retype it and press enter ... and
the Century Byte in the CMOS is updated to 20 - and your machine is
ready to work with the proper date after the Year 2000.

    That's all to solve the Hardware Part of the Y2K-problem on your

    There is still a slight Software-Problem left: some older Versions
of Windows, DOS or OS/2 might be not Y2K-aware. This might result in
some odd entries for the date in e.g. File Manager under Windows.
Especially the Win 3.1 versions are known to have some problems with
that. As far as I know Win95 is Y2K-aware mainly. I set the date to
01.01.2000 and saved an existing file under a different name again. The
File Manager showed the date as 01.01.00 - but on "Properties" it came
out correctly as Saturday, 1. January 2000. Some Win 3.1-versions show
01. January A?00 or such nonsense instead - however I think that
depends on the basic-DOS version mainly. I ran Windows 3.1 and Windows
for Workgroups 3.11    under PC-DOS 7.0 only and hadn't experienced any
such problems so far. It *might* be a problem if you use any older
DOS-Version before 7.0 - cannot say.
    It is a good idea to get the PC-DOS 7.0-Fix for Y2K. This fixes
problems with the Virus Scanner, Backup and Restore (which are also

    There is one major limitation which is worth to be mentioned: the
RTC-chip is limited to dates between 01.01.1980 and 31.12.2099. It
cannot handle dates before 1980 and after 2099 - but I guess there will
be only a few left-over PS/2 in working condition in the year 2100 ... 


As I read it, the upshot is that as long as your PC is 100% IBM
compatible, i.e. uses the same RTC chip or 100% comaptible RTC chip as
the IBM PC-AT, your hardware is compliant.

As an aside, some computer vendors we work with are talking about
monitors and printers being Y2K complaint.  This I don't get.....  

Jim Shorney                   -->.<--Put complaints in this box
Lincoln, NE, USA
Version: 2.6.2


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