107 lines
4.7 KiB
Diff
107 lines
4.7 KiB
Diff
From 1c8ce71c30b2acb8453b2b43c67052a6f9db2090 Mon Sep 17 00:00:00 2001
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From: Paul Eggert <eggert@cs.ucla.edu>
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Date: Wed, 10 Jun 2020 13:51:29 -0700
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Subject: [PATCH 10/47] =?UTF-8?q?French=20clocks=20stopped=20for=209?=
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=?UTF-8?q?=E2=80=B221=E2=80=B3=20on=201911-03-11?=
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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(Thanks to Michael Deckers.)
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* NEWS, theory.html (Accuracy of the tz database): Mention this.
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* europe (Europe/Paris): Model the 1911-03-11 transition as
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occurring at 00:09:21, not at 00:01.
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---
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NEWS | 7 +++++++
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europe | 30 +++++++++++++++++++++++++++++-
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theory.html | 7 +++++++
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3 files changed, 43 insertions(+), 1 deletion(-)
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diff --git a/NEWS b/NEWS
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index e3ab402..5289d4e 100644
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--- a/NEWS
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+++ b/NEWS
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@@ -16,6 +16,13 @@ Unreleased, experimental changes
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(Thanks to Géza Nyáry.) Also, the 1890 transition to standard
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time was on 11-01, not 10-01 (thanks to Michael Deckers).
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+ The 1911-03-11 French transition from +00:09:21 to +00 is now
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+ modeled as occurring at 00:09:21, not at 00:01. Legally, clocks
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+ stopped at 00:00 for 9 minutes, 21 seconds but this cannot be
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+ represented in tzdb, so tzdb instead represents the common
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+ practice of keeping an old clock running until the new clock
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+ started up. (Thanks to Michael Deckers.)
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+
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Changes to code
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The undocumented and ineffective tzsetwall function has been
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diff --git a/europe b/europe
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index f0acb42..4fa7119 100644
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--- a/europe
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+++ b/europe
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@@ -1326,6 +1326,34 @@ Link Europe/Helsinki Europe/Mariehamn
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# Françoise Gauquelin, Problèmes de l'heure résolus en astrologie,
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# Guy Trédaniel, Paris 1987
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+# From Michael Deckers (2020-06-10):
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+# Le Gaulois, 1911-03-11, page 1/6, online at
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+# https://www.retronews.fr/societe/echo-de-presse/2018/01/29/1911-change-lheure-de-paris
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+# ... [ Instantly, all pressure driven clock dials halted... Nine minutes and
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+# twenty-one seconds later the hands resumed their circular motion. ]
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+# There are also precise reports about how the change was prepared in train
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+# stations: all the publicly visible clocks stopped at midnight railway time
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+# (or were covered), only the chief of service had a watch, labeled
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+# "Heure ancienne", that he kept running until it reached 00:04:21, when
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+# he announced "Heure nouvelle". See the "Le Petit Journal 1911-03-11".
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+# https://gallica.bnf.fr/ark:/12148/bpt6k6192911/f1.item.zoom
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+#
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+# From Paul Eggert (2020-06-10):
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+# French time in railway stations was legally five minutes behind civil time,
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+# which explains why "old time" ran to 00:04:21 instead of to 00:09:21.
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+# The Brooklyn Daily Eagle Almanac (1912), page 494, says:
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+#
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+# ALL CLOCKS STOPPED IN FRANCE.
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+# On March 10, 1911, all clocks in the Republic of France were stopped
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+# for 9 minutes and 21 seconds. This was in obedience to a measure
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+# adopted by the French Senate, which went into effect at midnight....
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+# Owing to this change in time a question arose in the French press as
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+# to whether or not a child that was born and died within the elapsed
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+# time could be said to have legally lived.
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+#
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+# tzdb has no way to represent stopped clocks. As the railway practice
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+# was to keep a watch running on "old time" to decide when to restart
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+# the other clocks, model this as a transition for "old time" at 00:09:21.
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#
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# Shank & Pottenger seem to use '24:00' ambiguously; resolve it with Whitman.
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@@ -1395,7 +1423,7 @@ Rule France 1976 only - Sep 26 1:00 0 -
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# on PMT-0:09:21 until 1978-08-09, when the time base finally switched to UTC.
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# Zone NAME STDOFF RULES FORMAT [UNTIL]
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Zone Europe/Paris 0:09:21 - LMT 1891 Mar 15 0:01
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- 0:09:21 - PMT 1911 Mar 11 0:01 # Paris MT
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+ 0:09:21 - PMT 1911 Mar 11 0:09:21 # Paris MT
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# Shanks & Pottenger give 1940 Jun 14 0:00; go with Excoffier and Le Corre.
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0:00 France WE%sT 1940 Jun 14 23:00
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# Le Corre says Paris stuck with occupied-France time after the liberation;
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diff --git a/theory.html b/theory.html
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index ffa3b4d..de105f2 100644
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--- a/theory.html
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+++ b/theory.html
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@@ -691,6 +691,13 @@ href="https://www.dissentmagazine.org/blog/booked-a-global-history-of-time-vanes
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<code><abbr>tz</abbr></code> database requires.
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</li>
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<li>
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+ The <code><abbr>tz</abbr></code> database cannot represent stopped clocks.
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+ However, on 1911-03-11 at 00:00, French clocks were changed by
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+ stopping them for 9 minutes, 21 seconds. This is approximated
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+ in <code><abbr>tz</abbr></code> as a transition from 00:09:21 back
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+ to 00:00:00 that day.
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+ </li>
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+ <li>
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Sometimes historical timekeeping was specified more precisely
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than what the <code><abbr>tz</abbr></code> code can handle.
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For example, from 1909 to 1937 <a
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--
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1.8.3.1
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