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Re: [Ntp] Finding leap-seconds.list

Tony Finch <dot@dotat.at> Thu, 08 November 2018 17:01 UTC

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Date: Thu, 08 Nov 2018 17:01:16 +0000
From: Tony Finch <dot@dotat.at>
To: Martin Burnicki <martin.burnicki@meinberg.de>
cc: Warner Losh <imp@bsdimp.com>, hidinginthebbc@gmail.com, ntp@ietf.org, eggert@cs.ucla.edu, dsibold.ietf@gmail.com, denis.reilly@orolia.com
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Subject: Re: [Ntp] Finding leap-seconds.list
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Martin Burnicki <martin.burnicki@meinberg.de> wrote:
>
> Some years ago I contacted the IERS folks and asked them if they
> couldn't also provide a leap second file in NTP/NIST format, and they
> started to do this. Yet the updated file was always available
> immediately when a Bulletin C was published.

It isn't quite as reliable as that, I'm afraid.

In June 2017 (shortly before Bulletin C 54) the IERS Leap_Second.dat file
nearly expired becuse it wasn't updated to reflect Bulletin C 53. That
didn't add any leap seconds, but the IERS data file lists both the date
and number of the most recent Bulletin C and its expiry time, and those
details should be correct.

(I notice these things because I have some code which maintains leap
second listings in the DNS in various formats at leapsecond.dotat.at. My
script fetches data from the IERS, NIST, and USNO, and compares them for
consistency before updating the DNS, and in recent years there has usually
been a significant delay updating at least one of the source files after
Bulletin C is promulgated.)

Tony.
-- 
f.anthony.n.finch  <dot@dotat.at>  http://dotat.at/
the quest for freedom and justice can never end

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