[tz] Proposed reversions, for moving forward
eggert at cs.ucla.edu
Sun Aug 10 18:50:27 UTC 2014
Lester Caine wrote:
> if the answers returned when checking historic data on a
> timezone depend on what data has been loaded then we are back with the
This is inherent to the current way the tz database is used. Different
software distributions use different versions of the tz database. They
install the tz database with different build-time options, getting
different sets of names. And distribution-specific patches can greatly
affect old time stamps: for example, Android discards all parts of the
database before 1901 (and after 2038!).
> I'd rather see a 'not available'
> rather than a 'this is todays guess'
Even for future timestamps? Most of them are "today's guess".
> I'd just be happy with hour correct.
The changes in question are pretty much all in that category.
> I CAN see a
> case for storing the version of tz used along with the timezone
Absolutely, if one is serious about provenance. One should record the
tz database version (including local changes and options) as part of the
provenance. One way to record this sort of information is OPM
<http://openprovenance.org/>. The tz database version is only a part of
this problem, as in the typical case one also needs to record the C
library version, kernel version, hardware version, etc.
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