[LEAPSECS] POSIX and C (Was: Re: ISO Influence)

Steve Allen sla at ucolick.org
Wed Dec 22 18:00:14 EST 2010

On Wed 2010-12-22T22:35:44 +0000, Ian Batten hath writ:

> On 22 Dec 2010, at 20:36, Steve Allen wrote:


> >On Wed 2010-12-22T18:46:56 +0000, Poul-Henning Kamp hath writ:

> >>Broadcast time *IS* civil time, it is broadcast as a service to

> >>civilians.

> >>

> >>Take Germanys DCF77 as example:

> >>

> >>DCF77 is the official legal time of Germany[1].

> >

> >By transmitting timestamps which are not UTC DCF77 is not in

> >conformance with ITU-R TF.460.


> The ITU's writ does not extend to specifying what the German

> government does within Germany to broadcast German civil time to

> German civilians.

On 1966-04-13 the congress modified 15USC261 to state that as of
1967-04-30 all US localities would transition to daylight time on the
same date. At that date WWV and WWVH were providing local standard
time at the transmitter.
Rather than introduce biannual 1 hour jumps into the WWV/H time codes
NBS chose to switch both to providing GMT as of 1967-04-28T21:00.
In 1968-12 the WWV* broadcasts switched to using what BIH then called
UTC rather than the notion of time from US observatories, but they
kept announcing it as "GMT".
On 1972-01-01 the WWV* broadcasts switched to broadcasting UTC defined
by the recent CCIR Rec. 460, but the announcers still said "GMT".
On 1974-01-01 the WWV/H broadcasts made no change in the time scale,
but the announcers started calling it "UTC".

So at various points the US managed to change the time codes, the
voice announcements, the time scale, and the name of the time scale
all without the world coming to an end. As a result the NIST
broadcasts seem to stand out by conforming with TF.460.

Steve Allen <sla at ucolick.org> WGS-84 (GPS)
UCO/Lick Observatory Natural Sciences II, Room 165 Lat +36.99855
University of California Voice: +1 831 459 3046 Lng -122.06015
Santa Cruz, CA 95064 http://www.ucolick.org/~sla/ Hgt +250 m

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