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How the tz database works (2020)

81 points by jumbosushi

by jlev

1 subcomments

This change https://github.com/eggert/tz/commit/baea52df7ac9c4b53857556f... was a huge pain in my ass in 2013.
I was working in Libya on voter registration tools with the UN and the High National Election Commission. The government decided to not implement a planned TZ change, and didn't inform the public until the day of. Not the hardest thing we dealt with, that was a full country internet shutoff by a mob outside our data centre (https://www.bbc.com/news/world-africa-25481794). Sometimes the politics of a project are more complicated than the technology...
We did implement an all-SMS voter registration system, which was pretty cool. Hasn't been used much since, but it's all open source. https://github.com/hnec-vr

by shagie

0 subcomment

I've found the comments in the database files (e.g. North America https://github.com/eggert/tz/blob/main/northamerica ) to be an interesting documentation of the history of the definition of time for various areas. For example, Indiana https://github.com/eggert/tz/blob/main/northamerica#L846

by chaidhat

0 subcomment

Took a class with professor Paul Eggert at UCLA, the person who maintains this db. Super chill dude. In his exams, he makes sure to add a question he doesn't know the answer to himself.

by knagy

0 subcomment

One interesting thing I learned while I tried to handle local time and NTP on a Raspberry Pico is that the TZ environment variable (that's usually something like "Etc/UTC" pointing to a zoneinfo file) can contain a TZ config as well, like "CET-1CEST,M3.5.0/2,M10.5.0/3". [1]
[1] https://sourceware.org/glibc/manual/2.42/html_node/TZ-Variab...

by jjice

0 subcomment

Great write up. This is very informative. Yet another thing I've taken for granted and hope to continue to take for granted because it generally just works and the bugs are my own.

by wodenokoto

2 subcomments

Is the author using `/ #` as the prompt string? I find the commandline sections hard to read.

by ape4

2 subcomments

by foresto

0 subcomment