On Wed, 8 Jul 2020 09:21:00 -0400
James Knott
On 2020-07-08 08:36 AM, Dave Howorth wrote:
"The 64-bit timestamps used by NTP consist of a 32-bit part for seconds and a 32-bit part for fractional second, giving a time scale that rolls over every 232 seconds (136 years) and a theoretical resolution of 2−32 seconds (233 picoseconds)."
So the precision is 233 picoseconds, but the same article says: "NTP can usually maintain time to within tens of milliseconds over the public Internet, and can achieve better than one millisecond accuracy in local area networks under ideal conditions."
That is clock accuracy, not display. Over the long term, the display will be just as accurate as the original source, but might fluctuate in the short term or perhaps have a small bias.
According tohttps://en.wikipedia.org/wiki/WWVB WWVB broadcasts once every second so its precision is 1 second. It broadcasts 60 bits per second, so that's the limit of resolution.
Again, you're confusing accuracy with precision. Over the long term, the accuracy will be as good as the source. The dispaly might not be.
I don't think I am. I think you actually confused precision with resolution when you asked your original question: "Please note, precision refers to how accurately the clock can be read, not how accurate the clock is." What you describe as precision is actually the resolution. So you can reread my answers and substitute 'resolution' in some places, sure. Precision refers to random variations in the size of errors. There's no way to know that for 'openSUSE' in general; it will depend on what hardware you have, what program you're using to make the display, what else you're running on the machine, what kernel settings you have and perhaps other factors as well.
So I'm not clear why anybody would care about the precision of either. But clearly a well-installed NTP reference can be more accurate.
It's more of a curiousity thing. Also, with the pandemic, I have way too much time on my hands. ;-)
Indeed, as apparently have I. But as described so far your question doesn't have a sensible answer. Hence our disappearing up our collective a*ses.
In a note to Per, I mentioned "rate", which is the difference between a clock's accuracy and actual time.
Yes that's one of the easiest consequences of general relativity to demonstrate, these days.
It must be accounted for in calculations. What people might not be aware of is that you can have atomic clocks, that are part of the basis for International Atomic Time, at Boulder, Colorado and Greenwich, England and, because they're at different attitudes, will actually have different times. That difference has to be accounted for when the IAT is determined.
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