The Obscure System That Syncs All The World’s Clocks

Video written by Amy Muller

[fredinit]

Hats off to David Mills, NTP inventor and maintainer for close to 40 years, who passed away in January of this year.

[safebox]

I love that two of the universal constants of modern technology is a web address we can ping to get the current time, and a series of automated phone numbers we can call to do the same.

[jeffdege]

I was a relatively new Linux user back in the early 90s. The kernel was at version 0.99, and NTP support was brand new.
I was attending a local Unix Users Group, and the guy who'd be talking was just being introduced when it turned 7:00.
There were maybe 30 people in the room and at least 25 of them had their digital watches (this was back when digital watches were still thought to be a neat idea) set to beep on the hour. And all of them had their watches synced to their Unix system, as did I.
So there was one continuous beep as everyone's watch triggered. Not perfectly synchronized, they didnt all start at the same time, but the late beeps started before the early ceeps finished. So instead of multiple, closely spaced beeps, there was one continuous beep sweeping across the room, lasting perhaps 1.5 seconds.

[Denes]

6:29 Ben went to college and wrote in the script…
Description: written by Amy
Now that’s hilarious

[desmond-hawkins]

NTP is great, but it only allows you to sync clocks within a few milliseconds, and that's not precise enough when you want to sync database replicas in a DB that uses timestamps, like Cassandra for example. It's _usually_ fine, but there are better alternatives now and those are used mostly in datacenters. The most well-known is probably Precision Time Protocol (PTP), which gets you to sub-microsecond accuracy. There's also a new system called chrony, which is an implementation of NTP that improves its precision to similar levels to PTP (~70 nanoseconds).

[benjaminpera]

Minor correction, the building the NIST clock for NTP is in is actually on their Boulder campus, the Fort Collins clock ensemble operates as the source for radio time (WWVB) and as a backup clock. Many laboratories around the world synchronize their clocks with NIST using common view time transfer which acts like a calibrated GPS time signal.

[wraithcadmus]

It's one of those things that just works great, but when it doesn't it manifests bizarrely. In the modern web it's often login issues
Client: "Yes I'm logged in, here's my token valid from 09:00"
Server: "... but it's only 08:57, buzz off"

[ReyMysterioX]

Just to be nitpicky: If you're talking about the power grid, a lot of equipment on the grid needs even higher precision. That's why a lot of that equipment is directly attached to a GPS clock and PTP / IEEE1588 is used to propagate even more precise timing information.

[SvenDansk]

There's an old regularity rally saying: A man with one clock knows what time it is. A man with two clocks is never sure.

[johnchessant]

After a long night at the bar, a guy invites his friend to see his new apartment.
As they enter, the friend notices a large gong against the wall and asks, "What's with the gong?"
The guy says, "Oh, that's not a gong, that's my talking clock". He picks up the mallet and hits the gong.
From the other side of the wall they both hear, "Shut up! It's 3 in the goddamn morning!"

[bobafettjr]

My dad has a radio clock that adjusts its time based on the radio signal. It's cool to watch it set itself when you first put in the batteries. The hands zoom forward until the time is right.

[Hiro_Trevelyan]

The modern world is built on insane and incredibly passionate nerds.

[anushagr]

For people who dont know founder of ntp, David Mills, died in january of this year at the age of 85. RIP

[Alexis-ltzy]

Time go thru wire, OR time go thru HF radio waves -- WWV is an amazing thing, the ability for devices to get the time via radio pretty much anywhere in North America is very important

[jonathanmatthews]

I like that this HAI has a higher proportion of actual footage shot by the team, versus stock footage. Keep it up folks!!

[DomyTheMad]

i cannot even put into words the emotions i'm feeling over that cardboard pc-case, the idea of bees coming out of a pc case LET ALONE that pulling the entire case away from it's cables X.X
my heart hurts!

[vmofficial]

Lol Sam complaining about Ben at the end

[KevinBerstene]

I wouldn't really call NTP obscure, but then again I'm a network admin, so....

[Deveyus]

Wait till this man hears about PTP (Precision Time Protocol)

[repatch]

"Which you are, since that's the only country" and now I have coffee all over my keyboard... :)