[ntp:questions] ntp & system without a rtc

Richard B. Gilbert rgilbert88 at comcast.net
Fri May 10 18:48:56 UTC 2013

On 5/10/2013 10:36 AM, folkert wrote:
> Hi,
> I have a raspberry pi system. This is a computer without a real time
> clock. So everytime I power it on, it uses starts where it left off
> which might be days earlier. It is connected only very occasionally to
> the internet so syncing to that won't work. It does have, however, a gps
> connected. But as it is switched mostly for less than an hour, ntpd
> won't have the time to adjust the time to what the gps returns to it.
> So I was wondering: is there a utility/a trick out there that picks the
> current time from a gps and then "jumps" the time to what it should be?
> It does not need to be very accurate - a couple of seconds off is ok
> (just not hours or days).
> Any ideas?
> Regards,
> Folkert van Heusden

I think you may be out of luck on this one.  If you can run NTPD 24x7
you can have the correct time 24x7.  If you can't do this, NTPD is a 
poor choice.  The problem is that NTPD needs something like ten hours to 
select a time source and match the time!

There is another "product" called "chrony" that has MUCH faster 
convergence.  I't never used chrony and can't tell you much about it.

I run 24x7 and seldom have to shut down and restart.

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