[LEAPSECS] UTC Redefinition Advanced

Warner Losh imp at bsdimp.com
Sat Oct 23 15:55:16 EDT 2010


One point that the leap second haters make is that leap seconds are
hard.

There are a number of reasons for this, but the biggest one is
acceptance. Leap seconds are hard, so why implement them right,
people will just reboot, or ntp will slew the time difference out. It
just doesn't matter enough, we're close enough and the disruptions are
rare.

While some take that as things are OK with leap seconds, those people
that have real-time systems cringe. Because of this "crap is ok"
attitude, nobody gets leap seconds right. In fact, they get them
wrong in an amusing number of different ways. This "blind eye" to the
problem perpetuates the problem, even as more and more systems need to
get things right. 2010 is a radically different world than 1970 when
leap seconds were invented.

Since there are only a vanishingly small number of systems that get
them completely right, I would argue that the ITU's proposal merely
recognizes the rampant 'de-facto' standard of time keeping: people
only get it right in the absence of leap seconds.

While this is unfortunate for the syncrhonization of the directiont he
earth points to a time base that everybody uses, it is the only thing
that implementors can agree on enough to interoperate with and get
right.

Warner


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