[TUHS] First ARPAnet transmission

[Greg 'groggy' Lehey]

On Monday, 29 October 2018 at 10:19:43 -0400, Clem Cole wrote:
> On Mon, Oct 29, 2018 at 4:01 AM Michael Kjörling <michael at kjorling.se>
> wrote:
>
>> So 1969-10-30 05:30 UTC?
>
> I >>think<< it is more likely 06:30 UTC, as IIRC Daylight Saving Time
> finished mid-month so I think it would have been UTC+8:00 [not +7:00 which
> it would be now].

Yes, correct:

  $ TZ=America/Los_Angeles date -j 196910292230 +%s
  5419800
  $ TZ=UTC date -r -5419800
  Thu 30 Oct 1969 06:30:00 UTC

> If you want to be be 100% accurate and use UTC, then you would need to
> check a precise calendar that had all those details to see how the US had
> its clocks set on October 30, 1969.  The good news was the transmission
> stayed with the same time zone, which as I said was Pacific (UCLA is in Los
> Angeles area and SRI in the Bay Area - but both are California - which
> follows US, DST rules).  The question is what were the rules that were in
> effect that night.

That's in the time zone sources:

  # Rule NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
  Rule	US	1967	2006	-	Oct	lastSun	2:00	0	S
  Rule	US	2007	max	-	Nov	Sun>=1	2:00	0	S

So in 1969, DST ended on 26 October.

Greg

Of course, this didn't happen at *exactly* 22:30/6:30, but presumably
nobody at the time thought that people would still be talking about it
50 years later.

Greg
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