[LEAPSECS] ISO Influence

Magnus Danielson magnus at rubidium.dyndns.org
Sat Dec 18 20:18:12 EST 2010

On 12/19/2010 01:49 AM, Greg Hennessy wrote:



> On 12/18/2010 07:21 PM, Poul-Henning Kamp wrote:


>> But you forget an important fact Rob: In computing UTC doesn't

>> have leap seconds presently.


> UTC has leapseconds. If computing doesn't have leap seconds

> presently, then I would say that computing doesn't have UTC.

This is true, if we by "computing" means POSIX. As the POSIX standard is
defined, it can't implement UTC as it is currently defined. It do
however approximate it.

POSIX as extended by NTP kernel interface may however provide sufficient
information to represent UTC.

> Now, of Poul-Henning wants to start to figure out the cost

> to making existing software match the current reality, he

> can start any time he wants.

It would serve no point, as fixing that software is exactly why the
commercial forces have been blocking the extension of POSIX to have
proper UTC, and even if it would be an extension they see the risc that
all systems would require it and hence larger set of software needs to
be fixed.

In this sense the ITU "gives in" to commercial forces to avoid fixing
things in the software. On the other hand, they have been following the
POSIX-standard, so it has been useful for its purpose... just not
matching up for UTC needs.

I don't think the leap seconds as such is necesserilly a bad thing, but
I do see the points about them being problematic to "bake into" the
system. If they where known to a greater extent in advance, it would
resolve some of those issues. It would still require the fix of software
as such.


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