The threat that could bring the Internet to a standstill, and it will only take a second

Readers of a certain age will remember the anti-climax of the Y2K bug that failed to bring down modern civilisation in 2000, but now a new threat has emerged.

According to the International Earth Rotation and Reference Systems Service (IERS), a leap second is due to take place on 30 June to account for the slowing of the Earth’s rotational spin and based on previous instances, that’s bad news.

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In the past, leap seconds have brought chaos to online services all over the world with high traffic sites such as LinkedIn and Reddit taken down in 2012. In addition, all computer systems operated by the Amadeus IT group were disrupted, meaning Qantas airline staff had to check-in passengers by hand.

The problem can be traced back to the Unix software behind the majority of web applications, which was actually launched in 1970, before leap seconds had even been proposed. Currently, computers match their time against the IERS network to ensure accuracy, but leap seconds have proved problematic. In this case, the IERS tells the Unix software that the final minute of the day will have 61 seconds.

In fact, the leap second issue has persisted even after Google claimed to have found a solution. Back in 2005, the search engine giant found that if it added a few fractions of a second to its systems’ clocks at various points throughout the day, the missing second could be accounted for without major disruption. However, despite Google’s efforts, web services continue to be disrupted.

As the Earth’s rotation is not constant, the actual length of a day and year changes over time. To cope with this, leap seconds were introduced in 1972 and have since been implemented 25 times.

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Some have argued that the best way of avoiding disruption is to simply abolish leap seconds altogether, and that is a distinct possibility with the International Telecommunication Union set to vote on the matter later this month.ba