[tz] Utah may drop DST

Jonathan M Davis jmdavisProg at gmx.com
Thu Oct 16 08:25:19 UTC 2014

On Thursday, October 16, 2014 03:49:56 Zoidsoft wrote:
> This might seem like a stupid question, but now that most of the world is
> connected by computers, smart phones, etc... why don't we develop an app
> that collects time settings and standards along with GPS for every device
> world wide as to what is showing on the clock?  Such an app could then
> automatically generate zone rules along with location data for each of
> those rules.  It would be a complex exercise in set theory getting the
> program to recognize "groups" of similar data but I think it could be done.

The first question that comes to mind is how on earth each of those computers
would get the time in the first place. Its the TZ database that this list is
for that's used to give most of them the information that they need to give
the time in a local time zone rather than UTC. All that stuff like NTP does is
give the current time in UTC, so without something like the TZ database, all
any of those devices would know about would be UTC.

Also, time zone rules change over time, and we often need to know what they
are ahead of time, so trying to figure out what they are via AI would not only
be a mess, but it wouldn't even have the information that we need when we need
it. If all you cared about was generating a database of what a bunch of
devices _thought_ that the time was in a given time zone at different points
in time was, that would be one thing, but we care about having the correct
rules over pretty much as large a time span as possible - both in the future
and in the past. And what you're suggesting wouldn't work for that at all. AI
can be great for heuristics, but it's horrible if you need to know the exact
anwser to something - like what the time zone rules are _exactly_ for a given
time zone at any given point in time.

But really, what you're suggesting pretty much comes down to generating
information from a group of devices instead of looking it up in exactly the
same place that they look it up, because the only way that they know anything
about the local time zone that they're in is because of the TZ database. They
don't magically learn it just because a government announces it. They learn it
because their TZ database files get updated with it.

- Jonathan M Davis

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