SUMMARY: Using NTP and RTC commands - contention?

From: Brent Parish (
Date: Wed Mar 25 1998 - 09:17:33 CST

Thank you for your quick responses! Yes, it seems I did ask a dumb question (sorry!) Below is the original post, followed by the responses.

Thanks to:
Casper Dik [casper@holland.Sun.COM]
Seth Rothenberg []
Tim Evans []

* * * ORIGINAL POST * * *


  I am using a crontab adjust of the clock drift via NTP (now conveniently packaged with Solaris 2.6!) every half hour. What I am wondering is, will that adjustment be in contention with RTC when it tries to adjust for daylight savings? I just set up NTP two days ago and know little about it or universal time. Apologies in advance if this is a really dumb question.

Thanks very much -
Brent Parish

* * * RESPONSES (thanks!) * * *

 - - - - - Casper Dik [casper@holland.Sun.COM] wrote:

NTP doesn't care about daylight savings time; the kernel keeps time in

So NTP is not part of the equation.

RTC is run precisely because of summertime swaps as the x86 clocks
keep local time.

So when daylight saving time passes, the x86 clock is adjusted.

SPARCs keep time in UTC.


 - - - - - Seth Rothenberg [] wrote:

You did not mention in your post but you may know,
I would assume it would not be a problem anyway.
GMT does not change at the whim of congress.
I would assume NTP would use GMT for adjustments.
Otherwise, you could never have a computer in
another time zone or another country that
wants to synchronize. Their documentation
_ought_to_ say something on the subject. But,
it is par for the course if it doesn't...
Good luck.
PPS is there a timed server that is accessible
to the public on the internet? eg, in Greenwich?

- - - - - -Tim Evans [] wrote:

You don't need to run cron jobs. xntpd will run--and adjust your system

Tim Evans                     |    E.I. du Pont de Nemours & Co.  |    Experimental Station
(302) 695-9353/8638 (FAX)     |    P.O. Box 80357
EVANSTK AT A1 AT ESVAX        |    Wilmington, Delaware 19880-0357

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