Beware the leap second?

On June 30, an extra second will be added to the Bureau of Standard’s atomic clocks.  This is so that our clocks will align more precisely with the rotation and orbit of the Earth.  The fear is that this will throw off the world’s computers, and, particularly, the programs that run the internet.

Last time this happened, in 2012, it did throw off a number of Unix-based websites.  Google has a fix for its sites, but many people are nervous, though probably not as nervous as they were with the Y2K panic, when 1999 turned into 2000.

From This year’s Y2K: ‘Leap second’ threatens to break the Internet – Jan. 13, 2015:

Get your apocalypse bunker ready. This summer, a “leap second” will threaten to wreak havoc across the Internet.

Last week, the International Earth Rotation and Reference Systems Service (yup, that exists) declared that we’re all living about a second ahead of where we should be — the Earth’s rotation has slowed, and we’ll need an extra second for the planet to catch up. The IERS announced that the leap second will take place on June 30.

The problem is that the computer software controlling much of the Web doesn’t play nicely with leap seconds. The previous leap second, which took place in 2012, brought down Reddit, Yelp (YELP), LinkedIn (LNKD, Tech30), FourSquare, Gawker and StumbleUpon, among other sites and apps. Qantas’ entire computer system went down for hours, forcing employees to check in passengers by hand.

The code for most Web apps is based on Unix, software that traces its roots to 1970 — two years before leap seconds ever existed. Computers check in from time to time with the IERS’ network to make sure that they are telling the time correctly (like wristwatches, they have to be “rewound” every now and then).

When leap seconds happen, IERS tells computers that the last minute of that day will have 61 seconds. That makes Unix-based software go haywire.

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