Daylight Savings Time ended this morning – some musings on time

Over at BoingBoing, Cory notes that today was the ending of Daylight Savings Time in much of the US. You can imagine what the effect of changes in DST dates has on the authors of software that has to keep track of these things (like clocks that automatically switch). Not all places switch on the … Continue reading “Daylight Savings Time ended this morning – some musings on time”

Over at BoingBoing, Cory notes that today was the ending of Daylight Savings Time in much of the US.

You can imagine what the effect of changes in DST dates has on the authors of software that has to keep track of these things (like clocks that automatically switch). Not all places switch on the same dates. As more and more people travel the world with devices that track times and dates, the complexities of this  apparently simple system get more exposed and more difficult to deal with.

At a recent meeting of the CalConnect calendaring consortium I was astounded to learn that there is no official body that tracks timezone data around the world. The best information is in the tz database ( http://www.twinsun.com/tz/tz-link.htm ) which is maintained, as I understand it, on a completely voluntary basis by Arthur David Olson, a systems administrator at NIH, for whom this is not even his regular day job. This database is apparently the basis used by almost all operating systems and software around the world to keep track of timezone information. And there are some wacky things to keep track of – for instance, Myanmar is +6.5 hours from UTC, and Nepal is +5:45 hours!

Reading through the comments in the tz files is fascinating – for instance:

# From Paul Eggert (2005-07-26):
# We have wildly conflicting information about Mongolia’s time zones.
# Bill Bonnet (2005-05-19) reports that the US Embassy in Ulaanbaatar says
# there is only one time zone and that DST is observed, citing Microsoft
# Windows XP as the source.  Risto Nykanen (2005-05-16) reports that
# travelmongolia.org says there are two time zones (UTC+7, UTC+8) with no DST.
# Oscar van Vlijmen (2005-05-20) reports that the Mongolian Embassy in
# Washington, DC says there are two time zones, with DST observed.
# He also found
# http://ubpost.mongolnews.mn/index.php?subaction=showcomments&id=1111634894&archive=&start_from=&ucat=1&
# which also says that there is DST, and which has a comment by “Toddius”
# (2005-03-31 06:05 +0700) saying “Mongolia actually has 3.5 time zones.
# The West (OLGII) is +7 GMT, most of the country is ULAT is +8 GMT
# and some Eastern provinces are +9 GMT but Sukhbaatar Aimag is SUHK +8.5 GMT.
# The SUKH timezone is new this year, it is one of the few things the
# parliament passed during the tumultuous winter session.”
# For now, let’s ignore this information, until we have more confirmation.

There are now some efforts to get IANA to maintain an official timezone registry for the Internet, but I don’t know if it’ll get anywhere.

It’s a wacky world we live in.

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