| Re: [chrony-users] How to read the RTC value? |
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The rtc works correctly if it counts out its own seconds. It's seconds need
not be the same as UTC seconds for it to work although they should not be too
far off. It is not supposed to an accurate source of UTC time. Just good
enough to start of nptd or chrony with roughly ( within a few hours) the
correct UTC time. After that you use either a good clock (atomic clock, GPS
time,..) or an internet ntp server to get the time reallywall ( to msec or
microseconds which an RTC cannot do and was never designed to do) For nsec
accuracy you need to put in much more work and money, and it is easy to get
wrong (see the brouha about 10 years ago when neutrinos were measured to go
faster than light. It turned out to be clock problem at nsec accuracy, not a neutrino problem.
And that was a multi million dollar experiment, with some really very bright
people running it. It turned out to be a bad fibre optics connection between
the gps receiver and the experiment, which delayed the time signal by a nsec
or so). nsec are hard. microseconds are cheap (<$100) and easy (even I can do
it).
William G. Unruh __| Canadian Institute for|____ Tel: +1(604)822-3273
Physics&Astronomy _|___ Advanced Research _|____ Fax: +1(604)822-5324
UBC, Vancouver,BC _|_ Program in Cosmology |____ unruh@xxxxxxxxxxxxxx
Canada V6T 1Z1 ____|____ and Gravity ______|_ theory.physics.ubc.ca/
On Fri, 9 Aug 2024, Jan Claußen wrote:
[CAUTION: Non-UBC Email]Well, it is simple. I want to compare if the RTC syncing was successfull and compare
the times like I can with timedatectl. This way you can visibly verify that the RTC works correctly. I don't
want to calculate anything for this.
It is just one line more to add to the rtcdata command. I really don't understand why this was never
implemented.