[NelsonMinar]

On the flipside, clock sync for civilians has never been easier. Thanks to NTP any device with an Internet connection can pretty easily get time accurate to 1 second, often as little as 10 ms. All major consumer computers are preconfigured to sync time to one of several reliable NTP pools.

This post is about more complicated synchronization for more demanding applications. And it's very good. I'm just marveling at how in my lifetime I from "no clock is ever set right" to assuming most anything was within a second of true time.

[Uehreka]

I was doing something at work that involved calculating round trip times from/to Android devices, and learned that although it should be possible for NTP to sync clocks with below-second precision, in practice many of the Android devices I was working with (mostly Pixels 2-7) were off from my server and each other by up to 5 seconds, which blew my mind.

[toast0]

It's hard to keep a phone's clock closely synchronized because they experience a lot of temperature swings, going between pockets and hands and open air and sometimes in direct sun, and the processor goes between idle and 100% as well.

Once you get to internationa phones, you'll have places where the phone does not include all timezones and specifically is missing the actual local timezone, so automatic sync is typically disabled so that the time can be set so that the displayed time matches local time... even if that means the system time is not correct.

[Nextgrid]

Depending on carrier-specific configuration and firmware phones may be configured to prefer NITZ (time transmitted by the cellular network) instead of NTP. That time is probably what’s off and would explain your observation.

[winrid]

Yeah it can only do so much with varying latency

[raron]

> clock sync for civilians has never been easier

I don't think civilian clock synchronization was an issue since a long time ago.

DCF77 and WWVB has been around for more than 50 years. You could use some cheap electronics and get well below millisecond accuracy. GPS has been fully operational for 30 years, but it needs more expensive device.

I suspect you could even get below 1 sec accuracy using a watch with a hacking movement and listening to radio broadcast of time beeps / pips.

[ssl-3]

Both of the WWVB clocks I've owned have been very fickle about how they're placed because RF be that way sometimes, and Colorado isn't exactly nearby to my location in Ohio.

The first manufactured GPS clock I owned (as in: switch it on and time is shown on a dedicated display) was in a 2007 Honda.

But a firmware bug ruined that clock: https://didhondafixtheclocks.com/

And even after it began displaying the right time again, it had the wrong date. It was offset by years and years, which was OK-ish, but also by several months.

Having the date offset by months caused the HVAC to behave in strange incurable ways because it expected the sun to be in positions where it was not.

But NTP? NTP has never been fickle for me, even in the intermittently-connected dialup days I experienced ~30 years ago: If I can get to the network occasionally, then I can connect to a few NTP servers and keep a local clock reasonably-accurate.

NTP has been resolutely awesome for me.

[jasonwatkinspdx]

At this point the only clock in my life that doesn't auto set is the one on my stove, and that's because I abhor internet connected kitchen appliances.

[timschmidt]

Good ol' Oven Standard Time (OST).

[NelsonMinar]

One of the best features of my microwave is the ability to turn the clock off entirely. If it doesn't set itself I'd rather just not see it!

[amelius]

Same here. I wish there was an easy way around it (that doesn't require me to play sysadmin in my spare time).