Am I the only person impressed with Universal Coordinated Time?

Discussion in 'Apple Watch' started by djuzi, Apr 17, 2015.

  1. djuzi macrumors member

    Sep 22, 2013
    I saw this on the Bloomberg review of the Apple Watch. I thought it was so cool that on every Apple watch the Mickey Mouse feet will tap his feet in sync. I think that means the second hand will be in sync on all the other faces too?

    It's a small thing but something pretty neat to show the evolution of the modern day wristwatch. Or I'm just crazy and really antsy to get an order update #
  2. Armen macrumors 604


    Apr 30, 2013
    Apple does things like this all the time and no one cares. You should read about the technology in the little square iphone charger. It does some crazy stuff to keep the battery healthy.
  3. zacheryjensen macrumors 6502a


    May 11, 2009
    Eh, you're being misled a little by that poorly written review. UTC (abbreviation for Coordinated Universal Time) is basically a time zone. Little more (like clearly defined rules for leap seconds and such). What really makes the synchronized foot tapping possible is that all of the devices are using NTP to synchronize against the same remote clock. The accuracy of this process depends on the speed of your network connection but usually lands around 20-30ms. That's close enough to defeat human perception of error in something like the tapping animation.

    So yeah, it's kind of cool, but, it's nothing magical or even remotely new. I've been keeping my clocks in sync with NPT against NIST's clocks for decades.

    Apple's really leveraging just how much better computer clocks have been vs. mechanical clocks for a long, long time for keeping accurate time to appear impressive in the scope of horology. But, anyone watching that game for more than a few decades knows that cheap quartz watches have also been vastly superior to mechanical watches for accuracy in most cases. With the watch, it takes advantage of regular synchronization.

    Just like Macs, PCs, Linux computers, smart phones, tablets, and even dumb feature phones have for years.

    Again, not discounting how nice that capability is, just, pointing out it's nothing new and I'd have been shocked had it not been part of the watch's capabilities.
  4. vladzaharia macrumors regular

    Jul 5, 2010
    This is actually physically impossible to achieve. Yes, they will be close together, and your time will be correct, but to get perfect accuracy 24/7 would require the watch to query for time updates constantly and needs to properly account for things like latency in communications.

    As the article said, they're generally within 50ms of the current time, which means that there is a chance one or two feet will be slightly out of sync in a room. 90ms is generally known as the minimum that a human eye can see a delay, but because it's an animation, it might be a bit more obvious if you have them side by side. It'll be close, even imperceptibly so, but never 100% perfect.

    Dumbphones are the only ones in that list that don't actually use NTP sync. They sync from the cell tower.
  5. pmau macrumors 65816

    Nov 9, 2010
    I'm sorry to be anal, but it does not depend on the network speed, but on the constant latency of the packet round trip time.

    You can have avery slow connection, but both ends will learn by time stamping the packets and correct for latency over time.

    The "drift" is the change in latency and is weighted over time to compensate for short fluctuations.

    Speed (throughput) and latency are two very different things.
  6. Armen macrumors 604


    Apr 30, 2013
    The real question is when are we going to get together and do the Mickey Mouse River dance?
  7. zmunkz macrumors 6502a


    Nov 4, 2007
    Damn, well I guess that makes this watch useless in a relativistic frame for telling local time.
  8. sjinsjca macrumors 68010


    Oct 30, 2008
    Coordinated Universal Time (aka UTC) shouldn't impress you too much; it's basically Greenwich Mean Time, meaning the local time at the Greenwich Royal Observatory, whose location is the stake-in-the-ground defining 0 longitude among other things.

    Just about any computing device that can report local time can be set to the +0 time-zone, meaning UTC.

    Mickey's toe-tapping is cute and cool. Kind of a waste of CPU cycles, but adorable.
  9. dotnet, Apr 18, 2015
    Last edited: Apr 18, 2015

    dotnet macrumors 65816


    Apr 10, 2015
    Sydney, Australia
    The network speed doesn't actually matter much, NTP will account and compensate for that. Predictability of the network speed (or delay) is much more important, and affects the accuracy directly. If your network link delays vary wildly then your NTP sync will be worse. For that reason NTP is usually configured to check several sources, it will automatically pick the most steady one.


    No, it only needs to check with its NTP servers in certain (ever larger intervals), because NTP also has the ability to adjust ("discipline" in NTP speak) the internal device clock. In most computers time is kept by a software clock inside the OS kernel, and most Unix derived OSes have clocks that can be disciplined by NTP. NTP will monitor the drift of the software clock and dial in incremental adjustments, until the software clock runs very accurately in between NTP server connections.

    The iPhone also doesn't use NTP to keep time, it gets its time from the phone network. There are iOS apps (like Chronometer or Time from Emerald & Sequoia for example) that do use NTP, and will show the offset between NTP and iPhone time. Unfortunately, iOS does not allow NTP capable apps to discipline (or set) the iPhone clock.
  10. Wallabe macrumors 6502a

    Mar 15, 2015

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