Le Sun, 17 Dec 2006 18:49:51 +0000, rm a écrit*:

> Ivan Rajkovic <ivan@iep.physik.uni-essen.de> wrote:
>> On Fri, 15 Dec 2006 11:59:10 +0100, Niki Kovacs wrote:
>>
>>> Hi,
>>>
>>> Is there a simple way to synchronize my system clock, say, on startup? My
>>> laptop unfortunately has a broken battery, and everytime I disconnect the
>>> power cable, the clock freezes... only to resume activity at the next
>>> boot... which always makes me travel back in time )
>>>
>>> Cheers,
>>>
>>> Niki
>>
>> put this is /etc/rc.d/rc.local :
>>
>> /usr/sbin/ntpdate de.pool.ntp.org
>> /sbin/hwclock -w
>>
>> you can change ntp server, here is the list:
>> http://ntp.isc.org/bin/view/Servers/WebHome
>
> We still use rdate. We include the following in rc.local:
>
> /usr/bin/rdate -s 129.6.15.29
>
> Is there a reason to use ntpd over rdate?

No special reason for the use you make of this command.
It is quite similar to ntpdate, a direct bulk call to
get the date/time from NTP server(s).
Now, exactly for the same reasons as ntpdate, if you intend to
put this command in cron (especially more often than a 24H basis)
please consider using ntpd instead.
You won't do much harm to the ntp servers for a long time but
you might have to find some new ntp servers and/or ISPs ;-)

Loki Harfagr wrote :

> Le Sun, 17 Dec 2006 18:49:51 +0000, rm a écrit*:

>> Is there a reason to use ntpd over rdate?
>
> No special reason for the use you make of this command.
> It is quite similar to ntpdate, a direct bulk call to
> get the date/time from NTP server(s).

One think is against rdate and that is the fact that rdate only supports
the old RFC-868 time protocol, so its a bit harder to find a server who
supports this protocol.
--
Thomas O.

This area is designed to become quite warm during normal operation.

james <mentor@arisia.org> wrote:
> I wrote an rc.ntpd with status|start|stop|restart with logging and a
> logrotate configuration.

That script seems really nice. However, I am missing one thing: A call to
ntpdate before ntpd is started. If I remember right ntpd refuses to start
if the clock is more than 3600 seconds wrong. 3600 seconds only means one
hour.

If you have a computer with a broken cmos battery or you don't have UTC
time in cmos clock and switched between daylight saving the time might
differ more than 1 hour from the correct time. With such a time difference
ntpd might refuse to start when it is needed the most. A call to ntpdate
fixes this.

Another thing to consider for the script might be to write the right time
back to the cmos clock with "hwclock -w". If the cmos battery is OK this
will give a rather accurate time at the next reboot. Without the "hwclock
-w" the time might be wrong at each reboot until ntp is started.

regards Henrik
--
The address in the header is only to prevent spam. My real address is:
hc8(at)uthyres.com Examples of addresses which go to spammers:
root@variousus.net root@localhost

Henrik Carlqvist <Henrik.Carlqvist@deadspam.com> wrote in
newsan.2006.12.18.07.12.35.562270@deadspam.com:

> james <mentor@arisia.org> wrote:
>> I wrote an rc.ntpd with status|start|stop|restart with logging and a
>> logrotate configuration.
>
> That script seems really nice. However, I am missing one thing: A call
> to ntpdate before ntpd is started. If I remember right ntpd refuses to
> start if the clock is more than 3600 seconds wrong. 3600 seconds only
> means one hour.

I believe that you're right, but since my 433MHz Celeron time server has
a good CMOS battery I haven't run across that problem yet. ;v)

> Another thing to consider for the script might be to write the right
> time back to the cmos clock with "hwclock -w". If the cmos battery is
> OK this will give a rather accurate time at the next reboot. Without
> the "hwclock -w" the time might be wrong at each reboot until ntp is
> started.

I think that my slackware version, version 10.0, handles that as part of
the reboot/poweroff scripts. Maybe???

Anyway, thanks for the kind words. You are, of course, free to
take/alter/re-publish the script as you wish.

After I wrote that I started checking out more of the ntp package.
There're a lot of other scripts in the package but they don't seem to
work, as if they were written for a different version or distribution.
I'm a little vague as that was a while ago now.