[tz] Google moves beyond NTP

Paul Eggert eggert at cs.ucla.edu
Tue Nov 27 01:28:51 UTC 2012

As I understand it Google is running NTP, slightly modified to smear,
according to the equation

  lie(t) = (1.0 - cos(pi * t / w)) / 2.0

where Google doesn't say what they're using for w.
For more on this, please see:

Pascoe C.  Time, technology and leaping seconds.
Google Official Blog 2011-09-15

As far as I know this sort of leap-second munging was first proposed
by Markus Kuhn in 2005.  Kuhn has compared his proposal to what
Google is doing.  Please see:

Kuhn M.  UTC with Smoothed Leap Seconds (UTC-SLS).
2005-12-14, last modified 2011-09-15

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