[ntp:questions] Re: questions Digest, Vol 13, Issue 38

David L. Mills mills at udel.edu
Sun Oct 16 04:15:18 UTC 2005


So far as I know, the leapsecond code in the various Unices comes from 
my humble fingers, so the ntpd/kernel behavior I say on these wires is 
safe. However, I fear somebody else may have other fingers that might 
implement the code and court disaster if lit by an NTP client. 
Therefore, I have changed ntp-dev to (in the case only of the NIST 
leapsecond table) to announce the leap only in the month of June and/or 
December. I don't expect to live long enough for leap epoches to occur 
more often than that.


David L. Mills wrote:

> Greg,
> My message you quote means precisely what it says, nothing more, nothing 
> less. While the leap warning bits happen to be set now per NIST leap 
> second table, the leap will not be executed until the time so carefully 
> spelled out in my message.
> All NTP servers in range of the subnet carefully and purposely display 
> the leap warning. Those that use the NIST table will show it now until 1 
> January 2006. Those that derive it from a reference clock will show it 
> when the clock shows it. The leap will actually be implemented as 
> stated. The code was last verified using the WWV leap warning at the end 
> of 1998.
> Dave
> Greg Dowd wrote:
>> That would be a big problem if the ntp servers are broadcasting leap
>> warning now. 
>> Message: 3
>> Date: Fri, 14 Oct 2005 13:58:04 +0000
>> From: "David L. Mills" <mills at udel.edu>
>> Subject: Re: ntp servers reporting leap second
>>     erroneously?
>> To: questions at lists.ntp.isc.org
>> Message-ID: <dioddl$gc1$1 at dewey.udel.edu>
>> Content-Type: text/plain; charset=us-ascii; format=flowed
>> Rex,
>> What makes you think this is a problem? The leap second display is
>> entirely and with emphasis purposeful. There is in fact a leap second
>> intended for the end of the year. The NTP servers will in fact show that
>> indication exactly as intended. On the last day of this year the kernel
>> of those compliant systems will be advised of the leap and those kernels
>> will implement it on the last second of the year. Those kernels that do
>> not implement the leap will observe the leap in 900 seconds and then
>> regain accurate synchronization. What is your problem?
>> Dave
>> Greg Dowd
>> gdowd at symmetricom dot com (antispam format)
>> Technologist, TT&M Div.
>> Symmetricom, Inc. www.symmetricom.com
>> "The current implementation is non-obvious and may need to be improved."
>> _______________________________________________
>> questions mailing list
>> questions at lists.ntp.isc.org
>> https://lists.ntp.isc.org/mailman/listinfo/questions

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