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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."
The Financial Sector.
Also, synchronized robotics, precisely coordinated CNC, and a host of other applications. Primarily, it's where absolute time isn't the concern, but rather where arbitrary time must be consistent between multiple devices (accounting for propagation delays, failures, etc...). Of course, protocols like PTP solve this fairly neatly: this particular product solves a different problem, and probably isn't actually useful.
There are two time issues to consider. One is how close your environment is to true time. The other is how close your individual devices are to one another. Messaging time-critical information between devices is severely complicated when the two devices are not on the same plane time-wise. Atomic clocks and the like solve the first problem. PTP solves the second problem. NTP almost (95%) solves both, but falls short in certain extremely time-critical situations.
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Could you have done a google search yourself or something?
Then you might find this:
The RADclock project (formerly known under 'TSCclock') aims to provide a new system for network timing within two years. We are developing replacements for NTP clients and servers based on new principles, in particular the need to distinguish between difference clocks and absolute clocks. The term RADclock, 'Robust Absolute and Difference Clock', stems from this. The RADclock difference clock, for example, can measure RTTs to under a microsecond, even if connectively to the time server is lost for over a week!
If it's off by a known amount, I'd expect you could calculate the real value with some kind of mathematical equation.
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
GPS also provides an extremely accurate clock signal all around the world (after all, it comes from an atomic clock onboard the satellites). All you need is a GPS receiver. You can put most decent GPS modules into a "clock mode" where you lock their position on the globe and they optimize the calculations to give you the most accurate time.
NTP has been around for decades. Even Windows phones home for the time every so often.
What a fool believes, he sees, no wise man has the power to reason away.
The next generation protocol has already been invented too, the Precision Time Protocol (PTP) recorded as IEEE 1588, with open source implementations already available.
That's right. Also, PC clocks tend to be not that great, in terms of reliability of the frequency, and error such as clock drift.
Hence the general recommendation to use NTP to keep your clock in synch with a good time source; a good time source, being something such as an atomic clock, or a radio-based receiver that provides time from a good source.
A PC clock can easily have errors of 100 PPM or higher. Or ~10 seconds of drift per day
Factors that seem small such as temperature can effect the frequency of the clock crystal also
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)
The next generation protocol has already been invented too, the Precision Time Protocol (PTP) recorded as IEEE 1588, with open source implementations already available.
PTP isn't a replacement to NTP: it's trying to solve a different problem. It's not useful on a general company LAN, but rather on a network that controls robotics or measurement devices.
Some limitations of PTP:
* only one "grandmaster" clock, i.e., no redundancy
* no WAN connectivity; it's UDP multicast-only, and so not very routable
* no security/signing of timestamps; NTP has security extensions if you need to be able to trust the time
* patented by HP/Agilent; NTP is both open and free
http://www.meinberg.de/download/docs/ieee1588/meinberg_ieee1588_conference2005_whitepaper.pdf
PTP was designed for small subnets of systems where measurement instruments and robotic systems are running on. This isn't a general PC/server solution.