[ntp:hackers] Leap second list file

Warner Losh imp at bsdimp.com
Mon Jan 16 03:11:14 UTC 2012

On Jan 15, 2012, at 3:40 PM, Danny Mayer wrote:

> On 1/15/2012 3:16 PM, Warner Losh wrote:
>> On Jan 15, 2012, at 10:00 AM, Danny Mayer wrote:
>>> On 1/6/2012 10:35 AM, Havard Eidnes wrote:
>>>>>> Is this the proper way to act as an information provider in this
>>>>>> day and age?  My take is "No, it most certainly is not, and
>>>>>> instead it casts into doubt their long-term reliability as a
>>>>>> source of this information".
>>>>> Please point us to the official Norwegian site which hosts this
>>>>> information?
>>>> I thought one global official information source would be
>>>> sufficient?  It's also the only source documented in the NTP
>>>> documentation.
>>> Actually, part of the protocol indicates the leap second is coming up.
>>> You don't have to copy leap second files to get the notification. See
>>> RFC 5905 Section 7.3 on the LI bits. It gets set during the month in
>>> which the leap second is to be added or removed.
>> Except that you don't know how many leap seconds have elapsed.  This makes running the 'right' time zone impossible.
> There is no 'right' timezone. ntpd knows nothing about timezones. Only
> about leapseconds.

The 'right' timezone files need knowledge of the leap seconds.  If you also synchronize your time with ntpd, you need to know.  ntpd, itself, per se, doesn't necessarily need that file, but without leap second knowledge, you can't do it.  The main reason is that there are no leap seconds when you run the 'right' timezone in the kernel.  It is all done in the printing of time.


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