Computer chaos feared over 2015's leap second
Computer chaos feared over 2015's leap second
Andrew Griffin, The Independent 9:12 a.m. EST January 8,
2015
The year 2015 will have an extra second — which could
wreak havoc on the infrastructure powering the Internet.
At 11:59 p.m. on June 30, clocks will count up all the
way to 60 seconds plus an extra second. That will allow the Earth's spin to
catch up with atomic time.
The Earth's spin is gradually slowing down, by about two
thousandths of a second per day, but atomic clocks are constant. That means
that occasionally years have to be lengthened slightly, to allow the slowing
Earth to catch up with the constant clock.
But last time it happened, in 2012, it took down much of
the Internet. Reddit, Foursquare, Yelp and LinkedIn all reported problems, and
so did the Linux operating system and programs using Java.
The reset has happened 25 times since they were
introduced in 1972, but the computer problems are getting more serious as
increasing numbers of computers sync up with atomic clocks. Those computers and
servers are then shown the same second twice in a row — throwing them into a
panic.
If a computer is told to do an operation at the time that
is repeated, for instance, the computer is unsure what to do. Or if an e-mail
is received in that moment, it could find its way in the wrong bit of the
server.
Last time, Google anticipated the problem and built a
smart update, which it called "leap smear". It modified its servers
so that they would add a little bit of extra time every time they were updated,
so that by the time of the leap second they were already caught up with the new
time. It said when it laid out the plan in 2011 that it would use the same
technique in the future, when new leap seconds are announced.
Leap seconds were initially added at least once a year,
but have slowed since 1979. The U.S. wants to get rid of them entirely, arguing
that they cause too much disruption, but others have opposed the change.
Britain, for example, has said that the leap second
should stay. Getting rid of it would mean the end of Greenwich Mean Time, used
in some European and African countries, which is measured by the sun and would
no longer be accurate.
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