[ntp:questions] How to keep system time from drifting way off if only time source is internal (NMEA $GLL)?

Lennart Ramberg ramberg.lennart at gmail.com
Sat Jan 27 12:07:42 UTC 2007

On 1/27/07, Steve Kostecke <kostecke at ntp.isc.org> wrote:
> Lennart Ramberg wrote:
> >I want to keep my Linux system clock at UTC and I accept if it is
> >off with say max 1 *second* - even if it never gets connected to any
> >network. The only available source to be assumed is the NMEA-sentence
> >$GLL derived from a serial line (just two wires, no PPL-signal).
> It's all too simple. Just use the NMEA driver (127.127.20.x).


Now, a problem is, that I'm short of serial channels.
So, what if the NMEA-driver can't have exclusive access to the serial port?

Maybe the NMEA-driver could be just 'sniffing'? There is no need for
me to transmit through the driver, just to receive.

Or, just assume that the NMEA-sentence is magically accessable
internally in the system; Could information from it be fed/directed
into ntpd?

Or could the MNEA-driver be made to fetch the data from say a file
instead, where I could have planted the $GLL-sentence?

Or could the NMEA-driver be made to also pass all recieved characters
to a file (feature request?), so other programs could have acces to

Lennart Ramberg

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