[tz] EU Public Consultation summertime arrangements

Paul Eggert eggert at cs.ucla.edu
Wed Jul 25 21:13:56 UTC 2018

I tried to submit the drafted comments, and discovered that there was a 
3000-character limit. So I trimmed them a bit and attempted to submit the 
attached 2994-character comment instead.

The https://ec.europa.eu/eusurvey/runner/2018-summertime-arrangements website 
was confusing, though, and did not give me confirmation that I have successfully 
submitted a comment. I may have submitted duplicate comments. Oh well, duplicate 
paperwork is par for the EU.
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I am commenting as coordinator of the Time Zone Database (TZDB)[1] hosted by the Internet Assigned Numbers Authority. Most of the world's cell phones and computers use TZDB to track civil timekeeping.

Although keeping the EU rules unchanged would be simpler, it would not be much trouble to accommodate the abolition of twice-yearly clock changes in the EU, as was already done in Russia and other countries. However, the following technical points should be considered.

1. There should be at least a year's notice before changes take effect. Otherwise some computer-based clocks will likely operate incorrectly due to delays in propagating updates to software and data. The shorter the notice, the more likely clock problems arise.[2][3]

2. If rules are changed, the EU should publicly record member states' related changes to civil time so that interested parties can easily track them. For best results, the EU should record changes to civil time in EEA/EFTA countries, candidate countries, potential candidates, the Schengen area, and other countries not in the EU that decide to make a related change. This record would be purely informative, with no authority behind it.

3. If the EU abolishes twice-yearly clock changes, the resulting time should be considered standard time, not permanent summertime, to avoid conflicts with existing computer standards in widespread use. Permanent summertime is not supported by the POSIX.1-2017 standard[4], which covers most of the computer servers in the European Union.

4. If the EU abolishes twice-yearly clock changes, there likely will be naming confusion when interested parties discuss the new timekeeping or use computer applications. For example, if France and Germany decide to stay on UTC +02 all year, many English-language computer systems will likely call the new time zone "Eastern European Time (EET)" due to the long association between EET and UTC +02 even though neither country is in eastern Europe; conversely, some systems could call it "Central European Time (CET)" even though that name has long been associated with UTC +01. Although the EU does not specify time zone names or abbreviations, it should bring this problem to the attention of interested parties. Using new names might lessen confusion, e.g., using "Central European Union Time (CEUT)" for a new UTC +02 zone in France, Germany, and nearby countries.

[1] Time Zone Database, Internet Assigned Numbers Authority. 2018-05-01. <https://www.iana.org/time-zones>

[2] Changes to the tz database. 2018-05-01. <https://data.iana.org/time-zones/tz-link.html#changes>

[3] Johnson M. On the Timing of Time Zone Changes. 2016-04-23. <https://codeofmatt.com/2016/04/23/on-the-timing-of-time-zone-changes/>

[4] The Open Group Base Specifications Issue 7, 2018 edition, IEEE Std 1003.1-2017 (Revision of IEEE Std 1003.1-2008). See "TZ" in section 8.3, "Other Environment Variables" <http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_03>.

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