New leapseconds file available (valid to 28 December 2021)

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brian pardini

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Jan 22, 2021, 6:50:15 PM1/22/21
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A new `leapseconds' file in zic format that is valid to 28 December 2021
is now available at:

http://www.ncedc.org/ftp/pub/programs/leapseconds

Please update your systems with this new file.  (The EEW hosts have been
updated.)  Any long-running program that uses this file must be
restarted for it to recognize the new VALID line.

Official leapsecond decisions are published in "Bulletin C", the latest
of which can be found at:

https://datacenter.iers.org/data/latestVersion/16_BULLETIN_C16.txt

On Red Hat systems, the `tzdata' package also provides a `leapseconds'
file at `/usr/share/zoneinfo/leapseconds', which is updated in
accordance with the IERS Bulletin C.  It looks as if this package is
updated (and tested) several times a year:

https://access.redhat.com/articles/1187353

and in turn is updated from the `tzdata' development repository on
GitHub at:

https://github.com/eggert/tz

which also includes a file `leapseconds.awk' in order to "Generate zic
format 'leapseconds' from NIST format 'leap-seconds.list'":

https://github.com/eggert/tz/blob/master/leapseconds.awk


`/usr/share/zoneinfo/leapseconds' is the location for Red
Hat-/CentOS-/Fedora-based distributions.  I don't know about Arch,
Alpine, SUSE, Slackware, et al.  It looks as if Debian-based
distributions and FreeBSD (possibly macOS too?) use the NIST format for
their `/usr/share/zoneinfo/leap-seconds.list' file
(`/var/db/ntpd.leap-seconds.list' in FreeBSD).


Brian Pardini
--
Berkeley Seismological Laboratory
bpar...@seismo.berkeley.edu
+1 (510) 664-5140

Dietz, Lynn D

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Jan 22, 2021, 6:57:20 PM1/22/21
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Why 28 December and not 31 December ?


From: anss...@googlegroups.com <anss...@googlegroups.com> on behalf of brian pardini <bpar...@berkeley.edu>
Sent: Friday, January 22, 2021 3:50 PM
To: anss...@googlegroups.com <anss...@googlegroups.com>
Subject: [EXTERNAL] [anss-aqms] New leapseconds file available (valid to 28 December 2021)
 

 

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brian pardini

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Jan 22, 2021, 7:48:13 PM1/22/21
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Hi Lynn

On Fri, Jan 22, 2021 at 3:57 PM 'Dietz, Lynn D' via AQMS <anss...@googlegroups.com> wrote:
Why 28 December and not 31 December ?

To account for the possibility of the announcement in June 2021 of a
leap second being introduced on 31 December 2021.

The IERS Bulletin C announces whether or not a leap second will be
introduced at the end of a certain month, traditionally June or
December.  From Bulletin C 61:

``Leap seconds can be introduced in UTC at the end of the months of
December or June, depending on the evolution of UT1-TAI.''

But Bulletin C is updated every six months:

``Bulletin C is mailed every six months, either to announce a time step
in UTC, or to confirm that there will be no time step at the next
possible date.''

The latest Bulletin C (61) states:

``NO leap second will be introduced at the end of June 2021.''

So, I'm giving us some wiggle room at the end of December 2021 to make
sure that we've updated the `leapseconds' file with information from the
next IERS Bulletin C (62) due out sometime in June 2021.

Brian
 
 
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