REMINDER: LEAP SECOND

Mon Jun 22 19:36:32 UTC 2015

On Mon, Jun 22, 2015 at 8:44 AM, Stephane Bortzmeyer <bortzmeyer at nic.fr>
wrote:

> On Mon, Jun 22, 2015 at 12:38:28PM +0000,
>  Bjoern A. Zeeb <bzeeb-lists at lists.zabbadoz.net> wrote
>  a message of 17 lines which said:
>
> > So we need a new center of the universe and switch to stardate and
> > thus solve the 32bit UNIX time problem for real this time?
>
> Or simply use TAI which is the obvious time reference for Internet
> devices. Using UTC in routers is madness. Routers and Internet servers
> should use TAI internally and use UTC only when communicating with
> humans (the inferior life form which crawls on the Earth surface and
> cares about things like whether the sun is high at noon, for outside
> picnics).
>
>

If the Earth's core ever decides to have some real fun and causes there to
be a negative leap second (there is historical precedent for this, albeit
before the existence of UTC and atomic time) there  would be  a minute with
only 59 seconds, and I would expect things to break in new and creative
ways. We live in a relatively narrow slice of time (a few decades) where
this is a possibility, but it is a possibility. (Note that the number of
leap seconds per year has _slowed_ recently, corresponding to a speed up in
the long term averaged rotation of the Earth. If that speed up of the
Earth's rotation were to happen again, negative leap seconds would be
inevitable.)

The drift between the Earth's time and atomic time will just get worse over
longer time frames (see
http://www.ucolick.org/~sla/leapsecs/year2100.html ).  Even if UTC - TAI is
just fixed (i.e., no more leap seconds), that is just pushing the problem
down the road, and our grandkids will have to deal with leap minutes, or
our remoter descendants with leap hours.

>It's a problem with POSIX, not UTC.

Yes. I remember this being raised by people at the USNO back in the early
1990's, but there was no interest in changing POSIX. Too much installed
base was the reason stated IIRC.

My opinion is (and has been since the early 90's)  that the computer /
Internet world should just adopt IAT as the time system in use. That is the
best time we have, and it will never have steps. Yes, that means that you
would need something like a time zone file to set your system clock by hand
from local (UTC) time, but, then, we already have to have time zone files.

Regards
Marshall Eubanks