[LEAPSECS] Leap seconds ain't broken, but most implementations are broken

[Tony Finch]

Warner Losh <imp at bsdimp.com> wrote:

> We have a

> specific legacy standard called POSIX that's causing all kinds of

> issues that pop up when you least expect it 



I haven't mentioned the usual litany of NTP servers getting it wrong,
including servers run by national time labs. It's pretty embarrassing
that one of our main time distribution systems routinely screws up
leap seconds.


So the blame isn't just due to POSIX, or even mostly. Remember, NTP time
stamps are equal to POSIX time stamps with a constant offset regardless
of the number of leap seconds. The difference is that NTP actually
specifies how to handle leap seconds, and carries leap indicator bits
alongside the timestamp.


Even though NTP can represent current UTC correctly, it often gets leap
seconds wrong. It does not give confidence that we will be able to
reduce bugs by teaching more code about leap seconds, when NTP cares
about time and gets it wrong, and most code cares much less.


Tony.

--

f.anthony.n.finch  <dot at dotat.at>  http://dotat.at/  -  I xn--
  zr8h punycode



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