The great Polish Sea -or- We forgot Poland!

Raymond Chen


Open up the Date and Time control panel and go to the Time Zones tab.
Notice anything wrong with the world map?
Take a close look at northern Europe.

Depending on what version of Windows you have, you might
see a body of water where Poland should be.

Windows 95 didn’t have this problem

Windows 2000 did

whether your copy of Windows XP has this problem

on precisely what version you have.

Where did the great Polish Sea come from?

This weekend marks the end of Summer Time in Europe,
and the answer has to do with time zones.

Recall that the Windows 95 control panel highlighted your current
time zone on the map.
To accomplish this,
each time zone was assigned a different label in the time zone bitmap.
To draw the map, the portions of the world whose label was the same as
the selected time zone were drawn in bright green, and the parts that
were different were drawn in dark green.
So far so good.

When the

highlighting on the time zone map had to be disabled
all that happened was that the “color for the selected time zone”
was set to dark green.
The code still went through the motions of drawing the time zone
in a “different” color, but since the colors were the same at the end of
the day, the visual effect was that the highlighting was removed.

To determine which parts of the world are land and which parts
are sea, the time zone map enumerated all the time zones as well
as the labels associated with each time zone.
(You can see them in the registry under “MapID”.)
In this way, the land masses of the
world gradually emerged from the ocean as
the time zones claimed each spot of land one by one.

The shell team did make one fatal mistake, however,
obvious in retrospect:
It assumed that the world’s time zones would never change.
But what happens when a country changes its time zone,
as Poland did?
At the time Windows 95 was released, Poland was on its own
custom time zone, which Windows 95 called
“Warsaw Standard Time/Warsaw Daylight Time”,
but it didn’t stay that way for long.
Just within Windows 95 and Windows 98,
Poland’s time zone went by the following names:

  • Windows 95: (GMT+01:00) Warsaw
  • Windows 95: (GMT+01:00) Lisbon, Warsaw
  • Windows 98: (GMT+01:00) Bratislava, Budapest, Ljubljana, Prague, Warsaw
  • Windows 98: (GMT+01:00) Sarajevo, Skopje, Sofija, Warsaw, Zagreb

And that’s not counting the changes that were made in
Windows NT, Windows 2000 or
Windows XP or their service packs.
It’s not that Poland’s time zone actually changed that many times.
Rather, the way it was grouped with its neighbors changed.
I don’t know why all these changes were made,
but I suspect political issues played a major role.

As a result of all this realignment,
the “Warsaw Standard Time” time zone
disappeared, and with it, its associated land mass.
Consequently, the land corresponding to Poland remained underwater.
And for some reason, nobody brought this problem to the attention
of the shell team until a couple years ago.

In order to fix this, a new world bitmap needed to be made
with new labels (labeling the pixels corresponding to Poland as
“Central European Time”) so that Poland would once again emerge
from the sea.
Even though the highlighting is gone, the map code still needs to
know where every time zone is so it can raise them from the ocean floor.

Fortunately, all this will soon fall into the mists of history,
because Windows Vista has a completely rewritten time zone
control panel, so the mistakes of the past can finally be shed.
Let’s hope the people who wrote the new time zone control panel
remembered Poland.


Comments are closed.