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Free Clock Democratizes Atomic Accuracy

Posted by samzenpus on from the free-time dept.

schliz writes "A new, trial network of software-based clocks could give data centers and networks the accuracy of an atomic clock for free. The so-called RADclock analyses information from multiple computers across the internet by collecting the time from each machine's internal quartz clock, the time it takes for this information to be transmitted across the network, and comparing all the information collected to determine a time that is most likely to be accurate, so machines are calibrated across the network with up to microsecond accuracy — as good as that provided by a $50,000 atomic clock, researchers say."

11 of 178 comments (clear)

  1. A solution in need of a problem? by iserlohn · · Score: 5, Insightful

    NTP solved this ages ago by distributing atomic clock accuracy through the network.

    The only problem this will solve is where it is a private network not connected to public NTP servers (or organizations that do not trust public NTP). In that case, they would most likely be able to afford a atomic clock.

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    :. Ultimate Control Dedicated/VM Servers
    1. Re:A solution in need of a problem? by David+Chappell · · Score: 4, Insightful

      NTP solved this ages ago by distributing atomic clock accuracy through the network.

      The only problem this will solve is where it is a private network not connected to public NTP servers (or organizations that do not trust public NTP). In that case, they would most likely be able to afford a atomic clock.

      If one reads the explanation at the beginning of the article literally (as the person who wrote the summary did), the article does seem to say that this system averages the time from the cheap quartz crystal clocks in all of the computers in order to arrive at a highly accurate estimate of the true time of day. This of course is absurd. If all of the clocks start out between one and five minutes fast, they will converge on a time that is about three minutes fast. So much for microsecond accuracy!

      The article suggests that NTP did indeed solve this problem. Reading between the lines I gather that these researchers are developing the next generation protocol to replace NTP. This will allow all of the nodes to synchronize more tightly with whatever time source (such as an atomic clock) is used.

  2. Use GPS by maroberts · · Score: 2, Insightful

    They have atomic clocks on board and GPS receivers therefore give highly accurate time.

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    1. Re:Use GPS by Anonymous Coward · · Score: 1, Insightful

      But their rooftops do.

    2. Re:Use GPS by gnieboer · · Score: 2, Insightful

      Yes, you could, but what about the next leap second that changes it to 13 seconds (or worse, 11).

      If you wanted to keep your UTC accurate, you'd have to ensure you kept patching your software each time another was announced. Not the end of the universe by itself.

      But then, you've also got to deal with the problem of overlapping time (1/1/2015 12:00:00.5 happening twice), which for most people isn't an issue, but if you've got an application for which microseconds are important (like the high-volume financial trading types mentioned elsewhere), then that could be an significant issue.

    3. Re:Use GPS by mea37 · · Score: 2, Insightful

      Surely you're not suggesting that keeping accurate time with an atomic clock doesn't require manual intervention every time a leap second is introduced?

  3. Forgive my ignorance... by Pojut · · Score: 2, Insightful

    ...but in what situation would the time of day on a server or cluster need to be accurate down to a microsecond? Military, I would presume...but what else?

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  4. A new low in editorial savvy by EriktheGreen · · Score: 2, Insightful
    So, someone's invented ntp_time? That's only been around collecting time from time servers, many of which are atomic clock connected, since about 1985.

    I'm also pretty sure there are desktop clocks based on microcontrollers that implement ntp, so they display an accurate time without a computer.

    Most data centers that really care about time nowadays install a commonly available GPS unit on site, which syncs clock time with all the atomic clocks in the flying GPS constellation.

    Seriously, could the editor that greenlighted this have done a google search or something? It's getting embarrassing to read slashdot these days.

  5. Computer Clock resolution? by JSBiff · · Score: 1, Insightful

    What is the resolution of the built-in clock on most PCs? An Atomic clock might have nanoscale resolution, but if a computer's clock only has microsecond resolution, then it stands to reason that you can only synch the computer to within 1 microsecond of accuracy, no?

  6. Re:Nano not micro by pixr99 · · Score: 2, Insightful

    If your computer runs Windows it is probably using SNTP to simply set the clock. PCs are notoriously bad timekeepers and so the skew that you're describing is quite commonplace. The beauty of a full NTP implementation like ntpd is that, while it can be made to sync your clock, it's mostly about calculating your clock's drift so that tick intervals can be adjusted in order to obviate "hard" time synchronization. This eliminates those very wrong time readings in the hours/days before SNTP re-syncs.

  7. precision, accuracy... who cares by Goldsmith · · Score: 2, Insightful

    Let's just not pay attention to things like the difference between precision and accuracy anymore, it's too much work.

    I mean, there's no way that the same physical limitations would apply to all quartz clocks, right?