The solution is simple - move to TAI. That is the _true_ time, what
the master clocks actually keep. UTC is just a variant for creatures
living on the surface of the Earth.
On Fri, Jan 20, 2012 at 9:20 AM, Phillip Hallam-Baker
<hallam(_at_)gmail(_dot_)com> wrote:
If we are ever going to get a handle on Internet time we need to get rid of
the arbitrary correction factors introduced by leap seconds.
The problems caused by leap seconds are that they make it impossible for two
machines to know if they are referring to the same point in future time and
quite often introduce errors in the present.
1) No machine can determine the number of seconds between two arbitrary UTC
dates in the future since there may be a leap second announced.
Not true for TAI.
2) If Machine A is attempting to synchronize with machine B on a future
point in time, they cannot do so unless they know that they have the same
view of leap seconds. If a leap second is announced and only one makes the
correction, an error is introduced.
Not true for TAI
3) In practice computer systems rarely apply leap seconds at the correct
time in any case. There is thus a jitter introduced around the introduction
of leap seconds as different machines get an NTP fix at different points in
time.
Not an issue for TAI
4) Even though it is possible to represent leap seconds correctly in
standard formats, doing so is almost certain to exercise code paths that
should be avoided.
Not an issue for TAI
Note, also, that the ITU proposal is not to _remove_ leap seconds, but
to stop _issuing_ them (i.e., it could be rescinded fairly easily if
in say 20 years someone agitated strongly to bring leap seconds back).
Since the ITU does not look like sorting this out, I suggest we do so in the
IETF. There is no functional reason that Internet protocols should need leap
seconds.
I suggest that the IETF plan to move to Internet Time in 2015, immediately
after the next ITU meeting. Internet time would be TAI plus the number of
leap seconds that have accumulated up to the next ITU decision point. So if
UTC drops leap seconds at the next meeting the two series will be in sync,
otherwise there will be a divergence.
Makes no sense to me. Please don't continue to create more time scales
that are "TAI plus some arbitrary constant."
I believe that would make at least 4 separate ones (ET/TDT/TT, UTC,
GPS internal time, plus this), which would be IMO at least 4 too many.
If there is to be an internet time, it should simply be TAI. Then, the
conversion to UTC is just an addition, and there would be no reason to
have the messy interpolation during a leap second. just to change the addend.
Regards
Marshall
--
Website: http://hallambaker.com/
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