Software engineers and timekeepers rejoice as the world votes to end the leap second

Cal Jeffrey

Posts: 3,719   +1,168
Staff member
In a nutshell: Last week, an international coalition of scientists and government agencies voted to end the leap second, much to the relief of standards organizations and the tech industry. France's International Bureau of Weights and Measures (BIPM) and the National Institute of Standards and Technology (NIST) were just a couple of measurement authorities that chimed in on the vote.

The atomic clock was introduced in 1967 as a precise measure of the passage of time. It uses the vibrations of radioactive atoms and is accurate up to 1/15 billionth of a second per year, depending on the element used. Unfortunately, the Earth's rotation is not nearly as consistent as it varies and decays.

So in 1972, timekeeping authorities introduced the leap second to keep Coordinated Universal Time (UTC) and the standard day/night cycle in sync. It was an adjustment that asked devices to add one second roughly every 21 months. It seemed like a simple enough solution at the time, but it almost immediately proved problematic for computer programmers and the broader tech industry right out of the gate — an issue that has continued into the new century.

In 2012, a leap-second bug took down several websites, including Reddit, Mozilla, Gizmodo, Lifehacker, and more. In 2017, Cloudflare had a DNS blackout caused precisely at midnight on January 1 when the leap second kicked in that year. This year, Meta wrote a lengthy argument about why we should abandon the time adjustment.

Unlike the leap year (technically a leap day), which adds a day every four years, always ending February on the 29th instead of the 28th, leap seconds are far less predictable. While the suggested adjustment is approximately every 21 months, actual changes are based on the Earth's irregular spin. Since one second is a minuscule time increment, it is hard to pinpoint when the synchronization occurs upon reaching the target year. It's like trying to accurately hit a dart board when the distance to it keeps changing.

Around the turn of the 21st century, timekeepers began realizing that changes in time can negatively affect computers and software designed to deal with immutable time. It's hard to say whether these thoughts were provoked by the Y2K scare, but that seems reasonable.

They all agreed that something needed to be done, but nobody could devise a good solution. It took over two decades of debate between concerned entities to decide to simply end the leap second. However, Resolution D will not take effect immediately or continue indefinitely. The rule goes into effect in 2035 and will remain valid until 2135.

The International Telecommunication Union (ITU), responsible for transmitting universal time, still has to vote its approval at the World Radiocommunication Conference in Dubai next year. However, it is considered a formality since negotiations between the BIPM and ITU, so far, have proven favorable, indicating it is on board with the change.

The New York Times, notes that many in the standards community were thrilled with the near-unanimous decision.

"Unbelievable!" Time Department Director Patrizia Tavella with France's BIPM said. "More than 20 years of discussion and now a great agreement. [I] was moved to tears."

The National Institute of Standards and Technology's chief of time and frequency, Elizabeth Donley, said, "It feels like a historic day. There's probably a lot of celebrating being done in style [in France]."

Russia and Belarus were the only countries that did not vote to pass Resolution D. Belarus abstained, while Russia cited complications involving GLONASS — its system of global positioning satellites. They are hard-coded to account for leap seconds automatically.

Permalink to story.

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Hodor

Posts: 418   +301
Our idiocratic rulers in EU still can't make a decision to stop switching to DST and back, which causes economic problems to all the member states.

They don't care that most of Europeans want to stop moving their clocks twice a year. What matters is that pharmaceutical corporations have calculated that DST related shocks cause health problems. And that's exactly what they want. Because psychological and physiological problems increase the sales of anti-psychotics and other drugs.

So our resident traitors, the European Comission (EC), who always work against the people of EU, have decided to keep the clocks jumping forward and backward twice a year. Whatever is needed to keep the Big Pharma earning mucho dinero at the expense of public health.

I wouldn't be surprised that even in 2050 EU is still doing this stupidity that all the smart countries have abandoned decades ago.
 

psycros

Posts: 4,564   +6,868
Our idiocratic rulers in EU still can't make a decision to stop switching to DST and back, which causes economic problems to all the member states.

They don't care that most of Europeans want to stop moving their clocks twice a year. What matters is that pharmaceutical corporations have calculated that DST related shocks cause health problems. And that's exactly what they want. Because psychological and physiological problems increase the sales of anti-psychotics and other drugs.

So our resident traitors, the European Comission (EC), who always work against the people of EU, have decided to keep the clocks jumping forward and backward twice a year. Whatever is needed to keep the Big Pharma earning mucho dinero at the expense of public health.

I wouldn't be surprised that even in 2050 EU is still doing this stupidity that all the smart countries have abandoned decades ago.

Its the same in the US except its all about congressmen being able to have more daylight for their evening golf games.
 

0dium

Posts: 360   +448
So we get rid of the leap second because of sh!tty programming skills or lack thereof. This has come about because Facebook threw a hissy fit about dealing with the enormity of a leap second.
What? Have you read the article? It clearly states that it's because that leap second is hard to predict. The way it's done now is just a rough estimate which isn't accurate.
 

wiyosaya

Posts: 8,410   +7,845
I don't know what the programming fuss is all about. Programmers do not have to concern themselves with this. Why? Because the people who manage UCT handle it, and the correct time is distributed to all the network time servers throughout the world. When the user's PC makes a call to synchronize its time with the network time servers, the user's PC automatically gets the leap second. So, from a programming standpoint, there's nothing to do. Its all done by NTP. :D
 

Burty117

Posts: 4,698   +3,059
I don't know what the programming fuss is all about. Programmers do not have to concern themselves with this. Why? Because the people who manage UCT handle it, and the correct time is distributed to all the network time servers throughout the world. When the user's PC makes a call to synchronize its time with the network time servers, the user's PC automatically gets the leap second. So, from a programming standpoint, there's nothing to do. Its all done by NTP. :D
It's a bit more complicated in the high end datacenter world. They track time at a much higher precision and get more done every second. I think Linus did a video explaining why tracking time better than NTP is capable of means faster servers:
 

bviktor

Posts: 1,155   +1,686
So we get rid of the leap second because of sh!tty programming skills or lack thereof. This has come about because Facebook threw a hissy fit about dealing with the enormity of a leap second.
Or maybe because it's hard to justify the hassle. It'll take 105 years to be 1 minute off.

Or 6300 years to be 1 hour off...
 

bviktor

Posts: 1,155   +1,686
It's a bit more complicated in the high end datacenter world. They track time at a much higher precision and get more done every second. I think Linus did a video explaining why tracking time better than NTP is capable of means faster servers:
Linus is not an IT guy, he's a shop guy. He creates videos that drive many clicks, they don't need to be accurate. He threw around that "20 ms delay".... about what? Where? No one knows. It was one random example for a very specific use case somewhere, made by FB engineers with clearly questionable design choices.

You don't need an atomic clock in the data center, you just need a local NTP server. Which most datacenters already have, because for instance, all Active Directory Domain Controllers are NTP servers by default.

It makes absolutely no difference if you sync from your local atomic clock or from your local NTP server. The NTP server will be less accurate, but that doesn't matter - all your local nodes will sync from that, so all your nodes will be equally inaccurate. Fiber optics are extremely fast, normally within 1 ms on the LAN.

And if you go out from your datacenter, sub-second differences will never be the issue.

Btw, about that card itself,

> GNSS requires “clear sky” to function properly. Moreover there were several historical events of a short term time jumps by some GNSS constellations.

Yeah, that sounds great! All that hassle for... nothing.

If you really care about precision, sure, go ahead, switch from NTP to PTP. And have microsecond precision. But there's extremely few cases where it would make ANY difference in network performance, let alone that 100 times(!!) jump Linus mentioned. All that from an atomic PCI time card. Sure...
 
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Hodor

Posts: 418   +301
Considering that Global Crooks (who like to call themselves "elite") have decided to return the world economy back to Amish level as quickly as possible, I doubt by 2035 we'll be worrying about leap years, let alone leap seconds.

"Modern computers" in 2035 will require a steady stream of water to turn their gears.