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This Page Last Updated: 1998-Apr-14.

Instructions for Various Computers to use the ISO 8601 Year-Month-Day format:

IBM-compatible PCs that are using DOS (Version 5 onwards) or Windows (3.x,
95, 98, or NT) have all got provisions for the Year-Month-Day format already
built in. The Acorn RiscPC can also use this format. The instructions for
DOS and Windows, and for the Acorn RiscPC, are reproduced below:


For DOS users (Version 5.0 or later), add the line 'COUNTRY=086' in the
CONFIG.SYS file. Note that the 'DIR' command will still only use a 2-digit
year. However, many programs (eg Norton Utilities Version 4.50 etc) will
pick up the new country information and start working in the Year-Month-Day
format automatically. Referring to the DOS manual shows that several other
settings (for Scandinavian, East European, and Far-East (Asian) countries)
also use the Year-Month-Day format.


For users of Windows 3.x, 95, 98, and NT4, look at the options available in
the 'Control Panel'. See also the section 'Windows Year 2000 Bug' in this
document for some additional information.

Windows 3.x (3.1 and 3.11)

In Windows 3.x look at the 'International' Settings. In 'Date', click on
'Change'. In the 'Short Format Date' box, select 'YMD', Hyphen Separator,
'Show Century', 'Month Leading Zero' and 'Day Leading Zero'. In 'Long Format
Date' select 'YMD'; then use the pull down options to select a 4-digit year,
3-letter month, and leading zero on the day number. Finally, click on 'OK'.
In the 'Time Format' option ensure that '24-hour' is selected, and that a
leading zero is shown for digits '00' to '09', then click on 'OK'.

Windows 95, 98, NT4

Under Windows 95, 98, and NT4, look at the 'Regional Settings' option in the
Control Panel. At all stages here, several options are available in the drop
down boxes on screen. If the option that you want isn't listed, just go to
the main box where the definition is shown and type the new definition in,
in place of the one already there.

Select the Regional Settings Tab. Choose the correct Country and Language
from the drop-down list; that is English (British) if you are in the UK.
Click on 'Apply'.

Select the Date Tab. In 'Short Date Style' select 'yyyy-MM-dd' (this will
give the '1997-10-11' format in programs).

In 'Long Date Style' select 'yyyy-MMM-dd' (for '1997-Oct-11') or
'yyyy-MMMM-dd' (for '1997-October-11'). If you also wish the Day Name to be
shown then append ',  ddd' or ',  dddd' to the end of the Long Date Style
entry. Click on 'Apply'.

Select the 'Time' tab. Change the Time Format to 'HH:mm:ss' to give the
standard 24-hour system, then click on 'Apply'. Finally, click on 'OK'.

You may also wish to click on the 'Date/Time' icon. Check that you are set
for the correct Time Zone, else set it to UTC (GMT), and click on 'OK'.

Acorn RiscPC

The Acorn RiscPC doesn't use the ISO date format by default, but an add-on
'template' file is available to convert the machine to use the
Year-Month-Day date format. The 'ZIP' file with the template and all the
instructions has been compiled by James Miller G3RUH, and it is currently
available at:  <>. The file is
possibly called 'DATE.ZIP'; though the name of the file may have recently
changed to something else. The file can be used with a range of Acorn
machines, especially those running RiscOS 3 onwards.

Other Machines

Other operating systems may also allow the Year-Month-Day format to be used.
Consult the appropriate operations manual for details. As a bare minimum,
ensure that you try to use the full four digits for the year wherever
possible. Better still use the Year-Month-Day date format.

Windows Year 2000 Bug

The File Manager of Windows 3.x contains a bug such that when dealing with
dates after the end of the year 1999, the dates are displayed incorrectly.

For a two-digit year, 2000 is displayed as ':0' (colon zero), 2001 as ':1'
(colon one) and so on. From 2010 onwards the colon changes to a semi-colon;
2012 being displayed as ';2' for example. The Filing System used with DOS
and Windows is supposed to cover the years from 1980 to 2099. This part of
Windows fails for all dates after 1999.

For a four-digit year, the last two digits are shown as described above. The
first two digits are fixed as '19'. That is, 2005 is shown as '19:5' and
2016 is shown as '19;6', and so on.

There are fixes available from the Microsoft Web Site. One file is for
Windows Version 3.1 (W31FILUP.EXE), another is for the Windows For
Workgroups Version 3.11 (WFWFILUP.EXE) programs. They are buried quite deep
in the 'download' section; but do not completely fix the problem (see below).

This date corruption problem occurs due to the way that the program was
written (usually in Assembler). The ASCII characters after 7, 8, 9, are ':'
and ';' and so on. In effect when 'colon zero' is shown, the program is
trying to display 'ten zero'. This problem also occurs on some Amateur Radio
programs (both DOS and Windows) as documented in QST (ARRL), 1997-Aug, Page
69 and 70. The popular file viewer 'LIST' by Vernon D Buerg contains this
same bug in every version that I have seen from version 2.2d (1984) to 9.1k
(1997); that is in every one of the dozen or more copies that I have here.

Another Windows Date Bug

There is another Date Bug within Windows. In the Control Panel (Windows
3.x), in the International option, you can set the date format for DMY, MDY,
or YMD. You can have leading zeroes, or not. You can show century, or not.
An example Date and Time is shown in the format that you have selected,
based on the current 'system' date and time. The bug is that for a system
date for any of the years from 2000 to 2009, and when the 2-digit year
option is selected, only a SINGLE digit year is shown in the example date on

e.g.  31/12/3 (DMY)  or  12/31/5 (MDY)  or  7/12/31 (YMD)  and so on.

This test requires that you set your system clock to those dates to see the
effect. Do NOT run any time-limited software whilst doing these tests,
otherwise it will probably expire. The recent Windows Year 2000 Fix update
does NOT address this minor problem. With a 4-digit year selected, the
example Date is, however, displayed correctly.

Yet Another Windows Date Bug

In the new version of the Microsoft Windows 3.1 and the Windows for
Workgroups Version 3.11 File Manager, the version recently provided by
Microsoft (dated 1997-October) to fix the Y2K display problem (98, 99, :0,
:1, etc / 1998, 1999, 19:0, 19:1, etc), there are yet other date-related

Dates from 1980 to 2079 are now displayed correctly, but dates after 2079
are not. All dates after 2079 are reduced by 100 years: '2085' is displayed
as '1985' and so on. The Filing System used by DOS and Windows is supposed
to cover all years from 1980 to 2099. This shows that Microsoft cannot even
work to their own specifications. In addition, there is no on-screen
identification in the 'Help... About...' option to actually show if the old
or the new version File Manager is installed. Perhaps Microsoft will add
this when they get round to fixing the latest problems?

Adoption of ISO 8601

I really do not trust Microsoft to get it right as they still issue press
releases dated '2/4/98' and so on. The sooner they follow IBMs lead and
adopt the '1998-04-02' or '1998-Apr-02' or '1998 April 02' International
Format, as the default option, the better for all of us. IBM uses these
formats all the way through their Year 2000 Documentation, and on their
invoices; and has done so for many years. Many of their Web Pages are also
beginning to use it as well, especially in the file download areas.

Astronomers have worked this way for a very long time. Amateur Radio is now
gradually adopting this method, as it now realises the problems in
International communication that can be caused by differences in format
around the world. The IAU (International Astronomical Union) have recently
issued a document defining acceptable date formats for certain types of
astronomical software that have not, so far, used the ISO format. The IAU
have said that all systems MUST be ISO 8601 compliant by 1999-12-31. There
is a link to the IAU document from my main 'Y2K and ISO 8601' Web Page. The
Year 2000 and ISO 8601 Web Page is located at:
<> and also
has links to several other such related documents.

I have two video drivers here; they are dated '12/04/97' and '03/09/97'.
Which is the more recent? That depends if the dates are supposed to mean
'12th April' and '3rd September' or whether they mean 'December 4th' and
'March 9th'. The use of the 'yyyy-mm-dd' format, as defined in ISO 8601,
would remove this problem.

Ian Galpin,  1998 April 14th.