[ntp:questions] NTP Pool Server Costs me $40/mo in Bandwidth--is

Jochen Bern Jochen.Bern at LINworks.de
Tue Jun 24 16:25:37 UTC 2014


On -10.01.-28163 20:59, Miroslav Lichvar wrote:
> On Tue, Jun 24, 2014 at 03:46:15PM +0200, Jochen Bern wrote:
>> While I may have started from the same setting, I *did* try to put
>> myself into the shoes of astronomers and people operating satellite
>> systems (which, ironically, includes the popular stratum 0 of GPS).
> 
> Do these people work just with UTC? I'd think it's not accurate enough
> for their purposes and they need to include the current UTC-UT1
> offset anyway.

I'm pretty sure that you cannot operate a system like GPS without having
a better idea of UT1 than UTC, even if (IIRC) the satellites' downlinks
do not disseminate that data to the terminal units. No idea whether
looking at the USNO data once a week or day does suffice. All I can say
is that transit measurements are, by definition, not available as often
as one might like.

I don't think that anyone dealing with communication satellites (i.e.,
in orbit around Earth) or a telescope smaller than a house needs to
bother with UT1-UTC beyond the max offset guarantees currently in
effect, though.

>> Personally, I'd say that if a computer's clock's best suited to run on
>> TAI (or equivalent) and all data needs to be converted from it to $TZ
>> for the users, anyway, then having it run on TAI and disseminating and
>> handling a TAI-UTC delta along with the sync and timezone deltas seems
>> like the proper approach. But that wish doesn't change gettimeofday()
>> implementations all over the globe with a snap of my fingers, does it.
> 
> Agreed, but wouldn't switching to TAI everywhere be much more
> difficult than stopping messing with UTC and keep it a fixed offset
> from TAI?

Having computer clocks run on UTC(frozen) instead of TAI makes the
adaptation easier today, more difficult tomorrow ("do we *really* need
to work on that for (n<3) seconds of an offset!?"), and no less
necessary in the long run (when UT1-TAI has grown much larger than
UT1-UTC(frozen), and changes much faster as well). I prefer to have the
slope right where the ball needs to get rolling. ;-)

Regards,
								J. Bern
-- 
*NEU* - NEC IT-Infrastruktur-Produkte im <http://www.linworks-shop.de/>:
Server--Storage--Virtualisierung--Management SW--Passion for Performance
Jochen Bern, Systemingenieur --- LINworks GmbH <http://www.LINworks.de/>
Postfach 100121, 64201 Darmstadt | Robert-Koch-Str. 9, 64331 Weiterstadt
PGP (1024D/4096g) FP = D18B 41B1 16C0 11BA 7F8C DCF7 E1D5 FAF4 444E 1C27
Tel. +49 6151 9067-231, Zentr. -0, Fax -299 - Amtsg. Darmstadt HRB 85202
Unternehmenssitz Weiterstadt, Geschäftsführer Metin Dogan, Oliver Michel


More information about the questions mailing list