[tz] Leap seconds in the news
Paul Eggert
eggert at cs.ucla.edu
Tue May 19 19:12:30 UTC 2015
Amazon is smearing their clocks for 12 hours each side of this June's
leap second, so that the clocks will run smoothly but will be 0.5 s off
when the leap second is inserted. This affects only their management
console and backend systems; user EC2 instances are expected to do the
usual NTP dance. See:
Clarke G. Amazon cloud to BEND TIME, exist in own time zone for 24
hours. The Register 2015-05-19.
http://www.theregister.co.uk/2015/05/19/amazon_cloud_leap_second/
This is similar to the leap smear that Google has been doing since a
2005 leap second hit some of their servers, and the WSJ article says
that financial markets in Japan, South Korea and Australia are also
doing different variants of leap smear. Although leap smear ought to be
standardized (why would people want to dilute differently in different
countries or companies?), a previous attempt at standardization didn't
take. See:
Kuhn M. UTC with Smoothed Leap Seconds (UTC-SLS). 2011-09-16.
http://www.cl.cam.ac.uk/~mgk25/time/utc-sls/
A higher-tech approach to deal with leap seconds would be to launch
yourself into space at sufficient velocity so that when you return,
relativistic time dilation would cause your POSIX clock to match an
earthbound UTC clock. Unfortunately this requires time travel one
second into the future, whereas the current human record-holder, Sergei
Krikalev, has traveled only 23 ms into the future, and it took him 803
days' worth of orbiting to do it. See:
Cule M. The Future: Time Travel. Quite Interesting 2008-04-25.
http://old.qi.com/talk/viewtopic.php?t=11529
More information about the tz
mailing list