Re: What problems do leap seconds *really* create?

From: Markus Kuhn <>
Date: Wed, 29 Jan 2003 19:04:45 +0000

John Cowan wrote on 2003-01-29 17:56 UTC:
> The problem is that they are not announced much in advance, and one needs
> to keep a list of them back to 1972 which grows quadratically in size.

Is this a real problem?

Who really needs to maintain a full list of leap seconds and for what
application exactly?

Who needs to know about a leap second more than half a year in advance
but has no access to a time signal broadcasting service (the better ones
of which all carry leap second announcement information today)?

For pretty much any leapsecond-aware time-critical application that I
can think of, it seems more than sufficient to know:

  - the nearest leap second to now
  - TAI-UTC now
  - UT1-UTC now

This information is trivial to broadcast in a fixed-width data format.
(For the nitpicker: The number of bits to represent TAI-UTC admittendly
grows logarithmically as be move away from 1950. We know we can live
with that, as O(log(t)) is equivalent to O(1) for engineering purposes.)


Markus Kuhn, Computer Lab, Univ of Cambridge, GB | __oo_O..O_oo__
Received on Wed Jan 29 2003 - 11:05:04 PST

This archive was generated by hypermail 2.3.0 : Sat Sep 04 2010 - 09:44:54 PDT