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Free Clock Democratizes Atomic Accuracy
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."
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.
:. Ultimate Control Dedicated/VM Servers
I can imagine the speaking clock:
"At the third stroke, it will be, most likely, sixish"
This reminds me of an old joke about a retired Admiral who is responsible for sounding the morning cannon at the naval base, walking past a watchmaker's shop every morning and setting his pocketwatch to the correct time from a reliable old grandfather clock in the store window.
One day, on the walk in, he happens to see the watchmaker cleaning the store windows and mentions how he finds it amazing that the old grandfather clock keeps such flawless time.
"Oh, that old thing?" says the watchmaker. "It drifts horribly, and I have to reset it almost daily."
The Admiral then asks, "Since I've always noticed that it's reliable, from where do you get the time to set it?"
The watchmaker replied, "I use the report from the morning cannon at the naval base. It's always right on time."
Might want to doublecheck your facts. GPS knows about the time difference, which isn't 12 seconds either btw, it is 19. The complete time message, which includes the correct amount, is broadcast every 12.5 minutes, so its possible that when you cold boot a gps, it will be off some amount of time before that is received. (12 seconds is common for lots of GPS engines, they have built in correct for the first 7 seconds of correction, but need the updated time message after connection to get the rest of the update)
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?
No. You can sync up to fractions of a clock cycle fairly easily. On average you can only report the time at any instant with around 0.5 uS accuracy, but you can set the edge where it cuts over from one uS to the next as accurately as you want, given enough time to sync...
Slashdot car analogy is I change my oil 4 times a year, so you're saying I can't tell you when I change my oil with any accuracy higher than a whopping 3 months. Yet I assure you, if sufficiently motivated, I can "sync up" such that I change the oil precisely at midnight on the 1st of every third month, with a reportable accuracy of like an hour or so.
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger