Portable general timestamp format, not 2038-limited

[Paul Rubin]

sla29970 at gmail.com writes:
> Keep in mind that TAI is not legal time anywhere.  It is also not
> practical, for the TAI now is not available until next month.

If you mean they don't announce the average of the 350 atomic clocks
til a month later, well swell, but you can get sub-microsecond
accuracy from GPS references.

> >From a legal standpoint, either UTC or GMT (or both, if you read
> different languages in the EU documents) as kept by your national
> metrology lab is is the official time.  

According to <http://en.wikipedia.org/wiki/UTC>, UTC is derived from
TAI.  And according to the linked article that I think you mention,
comparing clocks on different contents gives uncertainty in the 10-50
ns range.  

> The national metrology labs are tasked to provide GMT or UTC as part
> of their charter, so that is *procedurally* the primary time scale.

Here we see the difference between UTC (the one synchronized to TAI)
and NIST UTC:  

  http://tf.nist.gov/pubs/bulletin/nistutc.htm

it's always within 20 nsec.  This seems like the kind of correction
that can be applied after the fact.  Anyway GPS time is probably
further out than NIST.

The difficulty/impossibility of computing intervals on UTC because of
leap seconds suggests TAI is a superior timestamp format.