[LEAPSECS] Leapsecs Listserve Moving.

[M. Warner Losh]

In message: <45C210AA.1020905 at usa.net>
            James Maynard <james.h.maynard at usa.net> writes:

: M. Warner Losh wrote:

: > In message: <7623093C-60C6-43CE-A6CE-D73557F18482 at noao.edu>

: >             Rob Seaman <seaman at noao.edu> writes:

: > : On Jan 31, 2007, at 8:52 PM, M. Warner Losh wrote:

: > : 

: > : > and 13 times when a leap second could have been inserted, but wasn't

: > : > :-)

: > : 

: > : Make that 1 out of 84 opportunities by the standard as written.

: > 

: > Well, bulletin C says:

: > 

: >  Leap seconds can be introduced in UTC at the end of the months of December 

: >  or June,  depending on the evolution of UT1-TAI. Bulletin C is mailed every  

: >  six months, either to announce a time step in UTC, or to confirm that there 

: >  will be no time step at the next possible date.

: > 

: > which is what I based my statement on.  The standard says that June

: > and December are primary, and March and October are secondary times

: > for a leap second.  Much of the gear in the field handles Jun/Dec OK.

: > Some handles Mar/Oct.  But much of it won't handle Mar/Oct or other

: > months.  ntpd handles only June/December.  This whole monthly thing,

: > while technically allowed in the UTC standard, as a practical matter

: > won't happen for a long, long time.  Even when the quadratic nature of

: > leapseconds causes their frequency to be more often, I suspect a

: > different mechanism will need to be in place.

: > 

: > Warner

: > 

: > 

: 

: The "standard," however, is not Bulletin C, but ITU-R Recommendation 

: TF.460-4, which reads (Annex I, section D.2.1): "A positive or negative 

: leap-second should be the last second of a UTC month, but first 

------------------------------------------------------------^^^^^

: preference should be given to the end of December and June, and second 

--^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

: preference to the end of March and September."


With all due respect, didn't I say exactly that when I said "The
standard says that June and December are Primary"?  I know that
Bullitin C isn't the Standard.  But does has the Earth Orientation
Center of IERS adopted TF.460-4?  Is IERS part of the ITU?  Is it
bound by the ITU recommendations?

I'm telling you that there's much gear that would fail if it ever was
not the first preference.  Any reference to standards will not change
gear in the field that knows Jun/Dec are it.

Warner