h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

At midnight on December 31st 2016, the powers that be (Time Lords?) are adding a leap second, to calibrate time along with the irregularities of the Earth's rotation. The last times this happened were on June 30th 2015 and June 20th 2012.

We have a guide entry on the subject at A19011061.

Wikipedia has a page at http://en.wikipedia.org/wiki/Leap_second

Now, I'm hearing some rumblings that some computer systems may fail to synchronise for a few moments after this time, and it could cause problems. Not Millennium Bug "Planes will fall out of the sky" type problems, but maybe a few servers or applications will crash somewhere.

So, can you foresee any problems this might cause in the real world?

No

Much like the millenium bug was the biggest pile of panic mongering crud I've ever seen.
Still the accountants did nicely out of it.

Well until the Brexit referendum campaign at any rate.

I could see some issues concerning the GPS system as it has to be accurate enough to handle relativistic effects, but since we've made similar adjustments in recent years, I feel safe assuming that the code involved in such systems is robust and flexible enough to deal with it.

So... not really.

I should have checked the Register before I posted:

In 2012, Altea (Australian Airlines), Reddit and LinkedIn were affected:
http://www.theregister.co.uk/2012/07/02/leap_second_crashes_airlines/

In 2015 there were only minor issues with Android and Twitter:

http://www.theregister.co.uk/2015/07/01/leap_second_bomb_bust/

This has happened before without any problems, so I won't worry about it.

The "Millennium Bug", on the other hand, was a very serious problem which required the combined efforts of tens of thousands of programmers to fix up. It certainly kept me busy for 14 months making sure everything was ready. We did such a good job that there were no problems.

Yes and I recall distinctly watching the millenium bug sweep the world in real time on the day it happened.

They were doing a nice graph at the time ranking the amount countries had spent on it versus the problems it caused.

Italy amused me a lot, they spent NTFA on it and had... NTFA problems.

On the other hand, there has been a major innovation in the last four years - there are now self-driving cars driving around in America. These rely very heavily on GPS.

It would be advisable for all such cars to stop five seconds before midnight and to remain stationary until five seconds past midnight.

So did Micheal Bolton and Samir Nagheenanajar but they got laid off anyway.

My company felt it was worth paying the money to fix the Millennium bug because we found that if we didn't, our systems would not work and the company would go out of business.

…and back in 2008, some Oracle servers crashed, as did Microsoft Zune devices (portable media players)

I strongly suspect that there will be some poorly designed systems implemented somewhere which don't take account of this irregular phenomenon, and we will get the odd failure report like we have the last few times they added a leap second. The question is whether any critical services may be affected (like airline bookings in 2008)

Link for 2008 crashes:

http://www.theregister.co.uk/2009/01/07/oracle_leap_second/

Link for Italy's experience.

http://www.washingtonpost.com/wp-srv/WPcap/2000-01/04/035r-010400-idx.html

It seems there's still two schools of thought on this. Unsurprisingly I tend to come down on the sceptics side. I recall that back in 1999 it used to really wind my brother up - who is and was a senior programmer for BaE Sytems - 'so a few servers are going to have trouble with the date? So what?' Wheras a bunch of accountants were basically refusing to sign off the audits of companies who weren't millenium proofed and therby in-essnence forcing large companies to do something about it.

The only people I found at the time who were most concerned about it were the people who worked for accountancy firms and those employed to do the fixing. Other than most people cared not and a lot of the IT people I knew were as sceptical as I.

Where it was not fixed there were very few recorded problems.

But anyway, it was 16 years ago, I expect we're rather more tied to computers than we were then.

Will the leap second happen everywhere at the same time or when each individual time zone reaches midnight? Will Australia get a leap second 12 hours before we do in the UK and be out of synch with the world in decreasing chunks for a whole day?

PP.

Leap seconds are added by the bods at Greenwich - I would presume it will be added to GMT and since others calculate their time from that then it will happen everywhere simultaneously.

Except in Italy, who will ignore it (and probably France too)

"It would be advisable for all such cars to stop five seconds before midnight and to remain stationary until five seconds past midnight." [Gnomon]

How you warn a self-driving car? Does it have ears?

Only if it's an Audi

I don't foresee any problems, but I've not decided how to spend the extra second yet.

I'll certainly be billing the time to the client. Any part of an hour is billed as a full hour, according to the contract.

Does this mean we have to hug and smooch all sorts of people for an extra whole second come the New Year moment? Damn !

The worst part is the extra second will be added to 2016, the clocks will read 11:59:60, making this year a second (and a leap day) longer.