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Date: Thu, 26 Jun 2003 15:19:50 -0600 (MDT)
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To: des@des.no
From: "M. Warner Losh" <imp@bsdimp.com>
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Subject: Re: cvs commit: src/sys/kern kern_tc.c
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In message: <xzpfzlw7dj3.fsf@dwp.des.no>
            des@des.no (Dag-Erling Sm=F8rgrav) writes:
: Warner Losh <imp@FreeBSD.org> writes:
: >   There will very likely be no leap seconds for a while, given how =
the
: >   earth is speeding up and slowing down, so there will be plenty of=
 time
: >   for this fix to propigate.  UT1-UTC is currently at "about -0.4s"=
 and
: >   decrementing by .1s every 8 months or so.  6 * 8 is 48 months, or=
 4
: >   years.
: =

: Not necessarily; UT1-UTC is required to be within +/- 0.9s, so a leap=

: second might be introduced early to avoid crossing the -0.9s barrier.=


At the current rate of drift, it will be about 48 months before we get
to the -0.9s barrier.  The leap second typically is scheduled 2-3
months in advance.  I'm told that those people that study these things
suspect the next leap second will be the December 2006 or June 2007.
But by 2050 or so we may be having 2 of them a year to keep up.

Also, there's a chance that there will be no more leap seconds ever,
with the UT1-UTC offset being allowed to grow to as large as an hour
so there's only one correction every 3k years or so.  But nothing has
been decided.

Warner