[ntp:questions] Re: simple time server
Richard B. Gilbert
rgilbert88 at comcast.net
Thu Aug 3 03:57:47 UTC 2006
Bryan Henderson wrote:
>>It takes a couple of hours for the program to figure out "what the time
> Remember that in this thread, I'm talking about a situation where the
> local clock of one computer is the time standard. If the time server
> is running on that computer, it knows by definition at all times
> precisely what time it is.
> There is a whole class of applications of network time service where
> it's important that a bunch of computers adhere to a time standard,
> but that standard doesn't have to be UTC. There's also a whole class
> of applications where wristwatch level precision is adequate. In my
> case, I can't imagine making use of more than about 100 ms precision.
> I think I've discovered in my brief investigation of the Ntpd
> reference implementation that it is not appropriate for those
> applications. I'm still trying to figure out whether NTP itself is.
If you are willing to settle for time to the nearest second you can use
rdate. If you need better; e.g. time to the nearest 100 milliseconds or
better, SNTP *might* do it for you but I wouldn't want to rely on it myself.
You can, if you wish, use ntpdate to set your clocks from some NTP
server. You could run it in a cron job once an hour or something like
that and it should keep your clock within a hundred milliseconds of the
server unless you have a machine with a really bad local clock. Ntpdate
does not provide the full functionality of ntpd and it is "deprecated"
and sooner or later will be dropped from the distribution.
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