[ntp:questions] Number of Stratum 1 & Stratum 2 Peers

Martin Burnicki martin.burnicki at meinberg.de
Wed Dec 17 09:45:00 UTC 2014

Harlan Stenn wrote:
> Martin Burnicki writes:
>> Harlan Stenn wrote:
>>> An alternative is that we get enough support to advance NTF's General
>>> Timestamp API, and then we can run systems on either TAI or UTC and
>>> these conversions will happen automatically.
>>> Since timescale files in the GTSAPI are "versioned", one could still use
>>> an obsolete leapsecond file, and while those UTC timestamps would be
>>> "wrong" if a new leapsecond was added, these timestamps would be
>>> correctable when a new version of the UTC timescale file was available.
>> Hm, that may not really help if the API returns a wrong UTC time stamp
>> which is then used to set the system time wrong.
> Anything on the box that uses UTC in this situation will be using an
> outdated UTC timescale, and when any newer versions are made available
> the library API will handle the conversion.
> Think of the case where you want to set an event for a future time - if
> you want to tag something with an absolute time of 10am UTC a year in the
> future, there's no way to know if there will be a leap second in there
> or not.  So as we get closer to the actual date, if the UTC timescale
> gets updated the absolute UTC timestamp will be properly adjusted as
> soon as we know.

I don't know if you are subscribed to the tzdist mailing list, on which 
there is actually a similar discussion:

Imagine you set up an event for April 2015 today, but you just don't 
know if DST will be in effect at that time, or not, just because the 
politicians haven't made the decision today. How will you handle this?

It may not be helpful if you get updated DST rules the day *after* the 
scheduled event.

On the other hand, when the event time approaches and you have the 
chance to get a DST rule update before the event time everything may be 
fine, if a decision is taken either to keep the UTC time *or* the local 
time for this event.

Since UTC is actually used in most computers to keep the system time and 
schedule events based on an accurate UTC time it may not be helpful to 
do this with post-processing.


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