[LEAPSECS] private smear goes public

[Brooks Harris]

Hi Stephen,

On 2016-12-01 01:08 PM, Stephen Scott wrote:
> Hello Brooks, Stephen;
>
> What's all this discussion about precision?
Merely about the math of their smear method.
>
> The smear has tossed the precision of the second SI out the window.
> This is totally unacceptable for an application that requires a 
> precise and stable frequency reference (telecommunications and 
> broadcast for example).
Yes, of course, but the whole purpose of the smear is to hide the Leap 
Second from the downstream 86400-second-day systems, especially 
operating systems, that may not be prepared to cope with the Leap 
Second. As I understand it, it compromises accuracy for reliability, 
buts that the best solution to avoiding potential wide-spread problems.
>
> Further, this is not the only smear algorithm.
> A proliferation of smears could be the best reason for getting rid of 
> the leap second.
As I read it I think Google's intention is to publish their method and 
algorithm in the hopes others may follow it. It would be better if 
everybody did it the same way, but it will remain to be seen if others 
will choose to follow the example.

-Brooks

>
> The time community is not monolithic and there are different 
> requirements of users.
> No single approach is likely to satisfy all.
> There is a requirement for a minimal set of standardized approaches.
>
> -Stephen
>
>
> On 2016-12-01 12:39, Brooks Harris wrote:
>> 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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>>
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