[LEAPSECS] Metrologia on time

[Warner Losh]

On Aug 4, 2011, at 3:22 AM, Ian Batten wrote:

> On 4 Aug 2011, at 06:27, Tom Van Baak wrote:

>> 

>> The internet is faster, more reliable, and far more global than

>> LF or short-wave timecodes ever were. Further, you now get

>> 4 or 5 digits of precision instead of just 1, as well as history

>> and predictions tens or hundreds of days in advance. All with

>> one line of code and a URL.

> 

> OK, so in that case (at risk of appearing like the village idiot asking why it gets dark in the evenings), why is |DUT1|>1s an issue?  If there are widely used dissemination formats that rely on it being <1, then it's a problem to make it larger: existing equipment won't understand and may be broken.  But if all consumers are taking a higher-precison value from a website, unless they have coded if (abs (dut1) > 1) { panic ("bad dut1") }, which is possible but seems needlessly paranoid, why do they care?


The error grows with DUT1, so using UTC to navigate, point telescopes, etc becomes harder.  Systems that used to ignore DUT1 errors since they were small would need to be updated.  Other than navigation by sextant though, I'm not aware of too many things that are DUT1 sensitive that don't get DUT1 from somewhere.

Don't confuse "all consumers of the broadcast DUT1" with "all consumers of DUT1".

Warner