[ntp:questions] Start of new GPS 1024 week epoch

Magnus Danielson magnus at rubidium.dyndns.org
Thu Aug 15 19:18:09 UTC 2013

On 08/15/2013 07:55 AM, David Taylor wrote:
> On 14/08/2013 22:07, Harlan Stenn wrote:
>> David Malone writes:
>>> Indeed - you need to have a timestamp within about ten years of
>>> correct before you start up, otherwise the problem will be worse.  Ntp
>>> has the same problem in figuring out the ntp epoch, though we've yet
>>> to see an ntp timestamp wrap around.
>> ntp-dev has a fix for this problem - while the original solution was
>> "make sure the clock is correct to within ~65 years' time" the new code
>> uses a "date of compile" value, and needs the system time to be either
>> 10 years' before that date or up to 128 years' after that date.
>> See http://bugs.ntp.org/show_bug.cgi?id=1995 for more information
>> (thanks, Juergen!).
>> H
> If you make that 9.5 years rather than 10 it might then cover the
> 500-week period mentioned by Magnus.
I do not mention a 500 week period. I mention a 1024 week period with
various phases, 500, 512 and obviously 729 (wrapped this Sunday as we
went into week 1753).
> Judging by some reports here, people may be using NTP more than 10
> years old.  Does this fix cause a problem in that case?
Not really. This problem is "common mode" to recent and 10 year old NTPs.


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