[time-nuts] 15 Seconds error...??

Attila Kinali attila at kinali.ch
Tue Jan 17 07:14:30 EST 2012

On Tue, 17 Jan 2012 06:57:22 -0500
Mike S <mikes at flatsurface.com> wrote:

> On 1/17/2012 2:04 AM, gary wrote:
> > My description of the problem would have been a thousand times better if
> > I mentioned monotonicity.
> UTC is monotonic. The problem is with people who assume that minutes 
> always have 60 seconds. In UTC, they don't - they can have 59, 60, or 61 
> seconds.

Not 100% true. It depends on the representation of UTC.
If you represent it as a seconds counter (like unix time or similar),
then you can have seconds that are two seconds long and theoretically
even back steps.

In reality, you will have a monotonic increasing counter (but
not strictly monotonic!) and this is a problem. Hence POSIX introduced
strictly monotonic time source (but with an arbitrary starting point).

Be also aware that most computer systems or devices that need an
RTC are using a similar seconds counter. And all these systems
are affected by leapseconds if they are not defined to use an
offset value to calculate UTC.

			Attila Kinali

The trouble with you, Shev, is you don't say anything until you've saved
up a whole truckload of damned heavy brick arguments and then you dump
them all out and never look at the bleeding body mangled beneath the heap
		-- Tirin, The Dispossessed, U. Le Guin

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