[LEAPSECS] presentations from AAS Future of Time sessions

[Warner Losh]

On Jan 12, 2014, at 9:31 PM, Dennis Ferguson wrote:

> I don't think the fact that they called it "GMT" at that point tells you

> anything since referring to UTC as "GMT" was pretty common in the US at

> the time.  Even the NBS did it.  WWV voice announcements referred to the time

> being transmitted as GMT from when they stopped announcing MST until 1974

> even though the time was very definitely UTC by then (including the DUT1

> advertisements).  This site

> 

>   https://soundcloud.com/shortwavemusic/sets/at-the-tone-a-little-history/

> 

> has a recording of the last announcement calling it GMT and the first calling

> it UTC; it sounds like DUT1 was 0.3 seconds.  The previous recording is the

> announcement of the change and indicates that the time they'd been calling

> GMT was in fact UTC.  If the NBS's radio service was calling UTC "GMT" then

> it shouldn't be surprising that computer programmer contemporaries might do

> that too.


NASA still calls UTC "GMT" See for example this article from yesterday:

http://www.space.com/17933-nasa-television-webcasts-live-space-tv.html

"The spacecraft was captured by astronauts on the station using a robotic arm at 6:08 a.m. EST (1102 GMT) and was attached to the station at 8:05 a.m. EST (1305 GMT)."

If rocket scientists can't get it right, then what hope to do others have.[*]

So seeing "GMT" in early Unix documents doesn't necessarily mean what you think it means, especially given the first hand accounts of participants on this list who specifically asked the people that originally wrote it what the intention behind the words was. POSIX changed the name to get the intention right, then "simplified" the actual rules to make ti "easier" to implement for the "vast majority" of users. A statement that was likely true in the 80's when standardization efforts were happening, but a statement that's become untrue as the userbase's sophistication has changed.

Warner

[*] See the archives of this group for a long discussion of why NASA uses this term, but it boils down to politics to keep the British happy and annoy the French...