[LEAPSECS] content of the NTP-aimed leap-seconds.list files

Rob Seaman seaman at noao.edu
Wed Feb 11 00:00:50 EST 2015


Just a reminder that even if future leap seconds cease (Chronos forbid!), they exist now and will always exist retroactively during these last several decades.  Features and infrastructure improvements such as we are discussing have value under all scenarios.

Rob
--

> On Feb 10, 2015, at 9:46 PM, Steve Allen <sla at ucolick.org> wrote:
> 
> The IANA tzdata now gets the complete leap second history
> information from the file leap-seconds.list that NIST
> has been publishing for the sake of NTP.
> 
> The NIST version of that file can be found at
> ftp://time.nist.gov/pub/leap-seconds.list
> (at least when the server is running, which I have found is not all
> the time).  There are multiple older versions of that file with
> timestamp integers in place of the "list".
> 
> The USNO has also been providing a version of leap-seconds.list at
> ftp://tycho.usno.navy.mil/pub/ntp/leap-seconds.list
> again with older versions named using a timestamp on the end.s
> 
> The IERS Paris bureau is also providing such a file.  That makes at
> least three separate sources for this information.  Each source has a
> different timestamp, a different expiration date, and different
> commentary text.
> 
> All three versions include a SHA checksum that can be used to detect
> unintentional corruption during data transfer, but that is not a
> digital signature that can be used to detect intentional corruption.
> 
> This particular format of file has been deemed acceptable as input to
> NTP daemons, for IANA tzdata, and in the experimental servers of the
> IETF tzdist protocol.  Comparing these with the DNS mechanisms being
> developed on LEAPSECS leads me to wonder ...
> 
> Are there other features which would be desirable as part of a file
> intended to robustly communicate the full known history of leap
> seconds?
> 
> --
> Steve Allen                 <sla at ucolick.org>                WGS-84 (GPS)
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