[tz] [Tzdist] Getting to closure Re: [tzdist] #31 (service): Include leap seconds?
martin.burnicki at burnicki.net
Fri Dec 19 16:49:39 UTC 2014
Paul Eggert wrote:
> On 12/17/2014 06:55 AM, Martin Burnicki wrote:
>> 2.) We have the leap second file from TZ DB. This file has a different
>> format than the NIST file, but as far as I can see is simply generated
>> from a file in NIST format by a script which is part of the TZ DB
>> package. Unfortunately the expiration date is *not* migrated into the
>> TZ DB's leap second file, so some important information is lost.
> Thanks for reporting this. I have installed the attached fix in the
> experimental tz sources on github and it should appear in the next tz
> release. I am cc'ing the tz mailing list to give them a heads-up.
>> 3.) We have a leap second file from IERS, which is once more in a
>> different format than the ones mentioned above.
>> In my opinion the IERS should be the authoritative source for a leap
>> second file (or table) since this is the institution deciding whether
>> a leap second is to be scheduled,
> I would prefer this also. However, the IERS file is copyrighted. That
> is why the tz database reproduces the NIST file (the NIST file is public
> domain). Other distributors of the IERS file might want to keep this in
We (maybe I) could contact the IERS folks once more. Maybe they are just
not aware that this copyright limits the files usage for TZ DB and/or
On the other hand, the intention of the file should be to use it, or the
information it provides, so why should there a problem extracting data
from it using a script and feeding the result to TZ DB and/or tzdist?
> Amusingly enough, the NIST file's expiration date disagrees with the
> IERS's. As a practical matter the NIST's date is more conservative and
> is a better choice for applications like tz and tzdist and this is
> another argument for using the NIST file.
Agreed. If the expiration date is only e.g. 2 days before the next
potential leap second then alerting may be too late, except if the
application alerts let's say 2 weeks (or whatever) before the current
date reaches the expiration date.
> Perhaps someday the IERS will address these two concerns.
Shall I contact the IERS folks with regard to this?
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