[LEAPSECS] Reliability

[Tony Finch]

On Tue, 6 Jan 2009, Rob Seaman wrote:


> To return to a previous point, Tony Finch wrote:

>

> > Note that there's no need for global co-ordination. Each country (or

> > county) can change when it is convenient for them. The effect would

> > probably be a shifting of timezone boundaries in lumps and bumps that

> > averages out to the overall DUT1 drift.

>

> These spiraling lumps and bumps in time are not acceptable.


They're certainly not very tidy :-) It's how DST works today, and
obviously this pisses off people like us who like technical stuff to be
implemented with more care and foresight than politicians use when mucking
about with clocks.


> (Also, I'm not sure saying "the politicians will fix it" is your most

> successful tactical point :-)



:-) I don't expect them to fix it, I expect them to continue fumbling with

it in much the same way as they do now - which is an inconvenience we know
how to deal with, both socially and in software (unlike leap seconds).


> On the other hand, the lumps and bumps from the timezone gimmick both

> accelerate with time, and pile higher and higher, one on top of the

> other.


Yes, that's the point, but they accelerate much much slower than leap
seconds, and the pile becomes unweildy ten times further in the future
than the UTC rules.


> Real time (the solar time that drives politicians in each county or

> country to reluctantly deal with this issue) will get further and

> further from civil time.  As a result, civil time will mean less and

> less.


I think for "real time" you mean "local civil time", and for "civil time"
you mean "atomic time".

The way we avoid the problems caused by politicians fiddling with
timezones is by using UTC instead of local time. In the future that role
would be taken by atomic time. Yes it won't trivially relate to any kind
of local time at any place on earth, like UTC and GMT, but that isn't what
we need it for.

Tony.
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