[LEAPSECS] Bloomberg announced its smear

Brooks Harris brooks at edlmax.com
Sat Sep 24 18:39:17 EDT 2016


Warner,

On 2016-09-24 06:02 PM, Warner Losh wrote:
> On Sat, Sep 24, 2016 at 3:46 PM, Hal Murray <hmurray at megapathdsl.net> wrote:
>> tvb said:
>>> Smearing is fine. It's a practical solution to an intractable problem. But
>>> forcing everyone to implement it the exact same way misses the point. You
>>> can't create a standard for your favorite set of time applications and then
>>> try to force it upon everyone else's time applications.
>> I think that's misleading.  If you are going to smear, there are a lot of
>> problems that go away if everybody uses the same parameters.
>>
>> Unless there are reasons to select one value over another, selecting one with
>> a coin flip is generally better than running incompatible implementations.
>>
>> This is still early in the deployment cycle.  It may be appropriate to
>> experiment.  Unfortunately, leap seconds don't happen often enough to make
>> that an useful approach to gaining experience.
> If it is still early in the development cycle, how can you say with
> certainty that all smears are acceptable to all environments? As this
> forum has discovered, the number of environments are quite large and
> the assumptions are more varied than any one participant can fully
> appreciate.
Indeed. Each of them have made judgments of how to do the smear based on 
their inventory of down-stream devices they hope to protect from the 
Leap Second. Each OS, each OS version, each DBMS, etc, may, or may not 
have, similar behavior. Note too the discussions of how they increment 
the smear so as to not upset some receiver's PPL. Now that they've 
deployed a smear and have a bazillion systems dependent on it they are 
going to be very reluctant to change what they're doing. Its all 
terribly indeterminate which is probably not what the financial system, 
government, justice system, and military wants to hear. You wonder if 
occasional system crashes aren't preferable to guaranteed inaccuracy.
-Brooks

>
> Warner
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