[time-nuts] June 30 2015 leap second

Martin Burnicki martin.burnicki at burnicki.net
Fri Jan 9 10:21:42 EST 2015

Tom Van Baak wrote:
>> I couldn't help noticing that Debian just issued an update
>> to tzone, so that means Linux systems now know about the
>> leap second.
>> -Chuck Harris
> Hi Chuck,
> "Linux systems now know about the leap second" -- this is a very
> dangerous assumption. And one reason why leap seconds have gotten out
> of hand the past decade.
> Just because you observe one tz update from Debian does not imply
> that all "Linux systems" on planet earth (or in space) magically know
> about leap seconds. There must be millions (billions?) of embedded or
> isolated systems -- from web servers to desktops to military systems
> to gadgets to Raspberry Pi's to mobile phones, that have not, and
> will not ever receive this update.

And that's where the new tzdist protocol comes into the game, which can 
be used to supply leap second information to time *servers* which need 
to send leap second warnings to their clients.

Systems which are simply time clients can receive the leap second 
warning via the usual protocols like NTP or PTP/IEEE1588. Of cours it 
must be sure that the information is also *evaluated* by the client 


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