[ntp:questions] Preparing for the leap second

Chuck Swiger cswiger at mac.com
Tue Jan 10 18:18:08 UTC 2012


On Jan 10, 2012, at 9:12 AM, Marco Marongiu wrote:
> I understand from "the NTP timescale and leap seconds" by Prof.Mills
> that modern ntpd doesn't step back the clock but either "freezes" time
> during the leap second, or it slightly increments it at each read until
> the "real time" catches up.
> 
> Did I get it correctly?

I think so, yes.

> If yes, then I would like to know:
> 
> - how can I tell if the operating system will freeze/slowdown, or step
> the clock?

Ask your operating system vendor, or look at the source code:

  http://www.freebsd.org/cgi/cvsweb.cgi/~checkout~/src/sys/kern/kern_tc.c

> - how can I simulate a leap second, and see how the system reacts?

Change the system time to a few minutes before any particular leap second that your OS knows about (CF leapseconds file, if it has one) and see.

Regards,
-- 
-Chuck



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