[LEAPSECS] private smear goes public

Brooks Harris brooks at edlmax.com
Thu Dec 1 12:39:51 EST 2016


Hi Stephen,
On 2016-12-01 02:49 AM, Stephen Colebourne wrote:
> More details on the developer site:
> https://developers.google.com/time/
>
> Notably this page:
> https://developers.google.com/time/smear
>
> which include "Our proposed standard smear" - "We would like to
> propose to the community, as the best practice for leap seconds in the
> future, a 24-hour linear smear from noon to noon UTC"
>
> Hip hip hooray! De facto standards for the win!
>
> Stephen
Ah, this is good. I'd missed that page yesterday.

I might suggest you good go a little further.

You say "Each second of time marked by Google's servers will be about 
13.9 μs longer than an SI second. "

Some developers may probably need to know exactly, or as exactly as 
possible, the ratio.

If I've got this right:

20 hours = 20 * 60 * 60 = 72000 seconds
Plus the Leap Second = 72001 second
So the ratio is 72001 / 72000 = 1.000013889 (rounded to 10-9th 
precision, nanoseconds)
This a repeating decimal number which may be denoted 1.000013(8).
Applications should be careful to provide adequate precision for the 
purpose.

-Brooks






>
>
> On 30 November 2016 at 21:05, Tom Van Baak <tvb at leapsecond.com> wrote:
>> I'm surprised no one has posted this news yet:
>>
>> "Making every (leap) second count with our new public NTP servers"
>> https://cloudplatform.googleblog.com/2016/11/making-every-leap-second-count-with-our-new-public-NTP-servers.html
>>
>> /tvb
>>
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>> LEAPSECS at leapsecond.com
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>>
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>



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