FW: Corrections to historic German timezone information

I'm forwarding this message from Sebastian Wangnick, who is not on the time zone mailing list. Those of you who are on the time zone mailing list should direct replies appropriately. --ado From: Sebastian Wangnick [mailto:sebastian.nospam01@wangnick.de] Sent: Sunday, January 27, 2008 2:02 To: tz@lecserver.nci.nih.gov Cc: time@ptb.de Subject: Corrections to historic German timezone information Dear Madam, dear Sir, I understand that the historic time zone database you maintain is the basis of calendar computations in many computer systems and programming languages, including Linux and Tcl. We are using said data in some of our applications. Many thanks for your effort. Please find attached a few modifications to your tz2007k data files, so as to bring them in line with the publications of the Arbeitsgruppe 4.41 of the Physikalisch-Technische Bundesanstalt at http://www.ptb.de/de/org/4/44/441/salt.htm. The mistake in tz2007k is that the special 1945 rules for East Berlin and the German Sowjet Zone mentioned in bullet point c) of the website above are applied to Germany in general. The modifications return Europe/Berlin to the standard rules a) and b), and introduce a new zone Europe/BerlinEast where a), b) and c) are applied. Cc to the PTB for information. Kind regards, Sebastian Wangnick -- Sebastian Wangnick Lammersdorfer Str. 61 D-52159 Roetgen/Rott

Thanks for doing that research. By design the tz database has separate entries only for regions that are in different countries now, or where clocks have diverged since 1970. This is to economize on our maintenance effort. Otherwise, we would need hundreds of zones just for Indiana, and thousands worldwide; our lives are too short to maintain all that stuff. Because of this rule, the 1945 divergence doesn't justify having two separate entries for Berlin. However, we should have the correct entry for Berlin, which raises the question: where is the commonly accepted center of Berlin? If the center is in the former Soviet zone, tz's Europe/Berlin should use what is in the proposed Europe/BerlinEast zone. If Berlin's center is in the former west-Berlin zone, Europe/Berlin should change to match what is in the proposed Europe/Berlin zone.

Dear Paul, I understand your concern. As proposed, the timezone Europe/Berlin would be applicable for the "western" countries of the state of Germany and the western part of Berlin, and Europe/BerlinEast for what was formerly first the Sowjet zone and later the state GDR, namely the "eastern" countries of the state of Germany (Mecklenburg-Vorpommern, Brandenburg, Sachsen, Sachsen-Anhalt, Thüringen) and the eastern part of Berlin. Creation of individual timezones for each of the countries of Germany is thus unneccessary. http://de.wikipedia.org/wiki/Bild:Deutschland_politisch_bunt.png However, if you can maintain only one timezone for the state of Germany, you should probably use the new definition of Europe/Berlin, limiting the error in 1945 to the smaller territory and population, but please note that this would be considered politically incorrect by said population. In this case we will privately maintain a modified copy of the tz database. Kind regards, Sebastian Wangnick -----Ursprüngliche Nachricht----- Von: Paul Eggert [mailto:eggert@CS.UCLA.EDU] Gesendet: Dienstag, 29. Januar 2008 01:00 An: Sebastian Wangnick Cc: tz@elsie.nci.nih.gov Betreff: Re: FW: Corrections to historic German timezone information Thanks for doing that research. By design the tz database has separate entries only for regions that are in different countries now, or where clocks have diverged since 1970. This is to economize on our maintenance effort. Otherwise, we would need hundreds of zones just for Indiana, and thousands worldwide; our lives are too short to maintain all that stuff. Because of this rule, the 1945 divergence doesn't justify having two separate entries for Berlin. However, we should have the correct entry for Berlin, which raises the question: where is the commonly accepted center of Berlin? If the center is in the former Soviet zone, tz's Europe/Berlin should use what is in the proposed Europe/BerlinEast zone. If Berlin's center is in the former west-Berlin zone, Europe/Berlin should change to match what is in the proposed Europe/Berlin zone.

On Jan 28, 2008 3:59 PM, Paul Eggert <eggert@cs.ucla.edu> wrote:
Because of this rule, the 1945 divergence doesn't justify having two separate entries for Berlin. However, we should have the correct entry for Berlin, which raises the question: where is the commonly accepted center of Berlin? If the center is in the former Soviet zone, tz's Europe/Berlin should use what is in the proposed Europe/BerlinEast zone. If Berlin's center is in the former west-Berlin zone, Europe/Berlin should change to match what is in the proposed Europe/Berlin zone.
I don't quite understand this. I do understand that it's overkill from the perspective of the TZ maintainers to precisely distinguish pre-1970 transitions, but it seems like the question of which part of Berlin to use should not depend as much on where the city center is but on the political continuity. markus -- Opinions expressed here may not reflect my company's positions unless otherwise noted.
participants (4)
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Markus Scherer
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Olson, Arthur David (NIH/NCI) [E]
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Paul Eggert
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Sebastian Wangnick