[LEAPSECS] L-format. Re: Crunching Bulletin B numbers (POSIX time)
Gerard Ashton
ashtongj at comcast.net
Mon Feb 21 11:25:52 EST 2011
On 2/21/2011 10:49 AM, Paul Sheer wrote, in part:
>
> No, it's my own idea.
>
> Hereby released to the world:
>
> "2010-02-21 09:40:27 -0600 L0024"
>
> I hereby name it "timestamp L-format".
>
> It solves the problem of absolutely specifying a future time where you
> don't know how many leap seconds there will be between now and then.
>
> With the L included it means that the timestamp can be absolutely
> converted to TAI and represents a precise caesium second on the TAI
> scale.
>
> Without the L it means a regular Posix time relative to the start of the
> day - so called "appointment time".
>
> In this way it is backwardly compatible.
>
> However if leap seconds are published ten years in advance, it would
> mostly obviate a need for these new timestamps.
>
> -paul
>
So if we suppose that Paul had actually invented and used this format
long ago, and is
just now telling us about it, I would interpret the timestamp as
follows, neglecting the date
for conciseness:
09:40:27 -0600 = 15:40:27 UT
At the time Paul wrote down the time stamp he believed TAI - UTC would be
24 s as of the time and date stated.
He therefore was specifying 15:40:51 TAI.
However, this prediction turned out to be wrong, TAI - UTC = 34 s in Feb. 2010.
So if I was searching through records labeled with UTC, I would look for
an event at 15:40:17 UTC. Have I got that right?
Gerry Ashton
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