[LEAPSECS] Meeting with Wayne Whyte

Mark Calabretta mcalabre at atnf.csiro.au
Tue Feb 1 00:12:50 EST 2011

On Mon 2011/01/31 17:10:45 PDT, Warner Losh wrote
in a message to: leapsecs at leapsecond.com

>Earlier threads have called this the 'non-uniform-radix' problem. It

>has been argued that there are no discontinuities in UTC, with the 59:60

>notation offered as proof. However, this moves UTC from a uniform radix

>that everybody is used to dealing with with to one with a


We all deal every day with a non-uniform and variable radix counting
system - "30 days hath September, ...".

Leap seconds differ from leap days only in their unpredictability.

>This table-driven non-uniformity might or might not

>technically be a discontinuity, but certainly is a pain in the back side.

This is like saying that the Gregorian calendar might or might not
technically be discontinuous. In truth it simply isn't discontinuous,
there is no discontinuity on Feb/29 or any other day.

As defined by TF.460, UTC is continuous, like the Gregorian calendar.
That's all there is to it.

>It is also a central problem of time_t: how do you map this

>non-uniform-radix notation onto a uniform count that must always satisfy

>properties that explicitly mandate a uniform-radix.

Vide the mapping of calendar date to Julian Date.

The fundamental problem is that there is no formula for determining
when leap seconds occur.

Mark Calabretta

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