[tz] Historical data

Paul Eggert eggert at cs.ucla.edu
Fri Sep 20 16:40:06 UTC 2013

David Braverman wrote:

> would it be difficult to create a build script that includes the
> historical data to the zic package if someone needs it, in addition
> to the post-1970 build script?

No, that should be doable.  Nobody's done it yet, though.
(Zefram has a prototype, which still has some kinks.)
We will probably do something like that at some point, if
only to support the few old entries we have lying around.

There's a more important issue than the technical mechanism.
Even to cover just standard 24-hour time with the Gregorian
calendar, a large amount of information would be needed to
fill out the pre-1970 data: it'd easily be an order of
magnitude larger than what we have now.  Who'd do the work
to maintain this?

"Maintain" doesn't simply mean "make sure it gets through
zic without complaint": one must also make sure it's
well-sourced and that there aren't any copyright violations
in it, and deal with any conflicts among sources, including
the inevitable political conflicts among contributors.

As this is out of our traditional scope, and we're already
swamped by too much email, it may be better to start a new
mailing list just for the topic of pre-1970 zones, a mailing
list that could discuss creating the historical database.
We'd gladly refer people to such a list.

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