nanog mailing list archives

Re: REMINDER: LEAP SECOND


From: Harlan Stenn <stenn () ntp org>
Date: Fri, 19 Jun 2015 21:53:38 +0000

Saku Ytti writes:
Hopefully this is last leap second we'll ever see. Non-monotonic time
is an abomination and very very few programs measuring passage of time
are correct.  Even those which are, usually are not portable, most
languages do not even offer monotonic time in standard libraries.
Canada, China, England and Germany, shame on you for opposing
leapsecondless UTC.

It's a problem with POSIX, not UTC.

UTC is monotonic.

Next year hopefully GPSTIME. TAI and UTC are the same thing, with different
static offset.

The General Timestamp API that Network Time Foundation is working on can
solve this problem.  People use different timescales for different
reasons.  The Agile folks like the "pigs and chickens" analogy: in a
bacon and egg breakfast, the chicken is invested while the pig is
committed.

It's lame for a chicken to dictate to a pig.

It's lame to change an existing Standard.  Leave that one alone and
choose to follow a new/different Standard.

If you don't have a system that can properly handle leapseconds, there
are several solutions to this, including:

- implement DLM's leap second process in the kernel, described over 20
  years ago 
- use the posix-right timezone files
- help Network Time Foundation get the General Timestamp API implemented
  and deployed, which will let folks use whatever timescale they want.

-- 
Harlan Stenn <stenn () ntp org>
http://networktimefoundation.org - be a member!


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