[ntp:questions] Using different timebase for ntpd

Patrick Loschmidt Patrick.Loschmidt at gmx.net
Tue Mar 24 10:47:12 UTC 2009


Thanks all for the answers so far.

> David Woolley wrote:
> As I understand it, he is replacing the kernel clock's role, so he 
> needs to replace all the system calls that read and discipline the 
> kernel clocks by ones that read and discipline the special hardware.

Correct. I have a PCI network card which runs it's own internal clock. I 
made a literature research and couldn't find anyone implementing NTP 
with hardware support for timestamping. Since I can modify the FPGA 
based card, my first step is to get NTPd discipline the clock on the 
card, that's why I have to replace all the system calls to the kernel 
clock ...

Richard B. Gilbert wrote:
> It might be useful to know exactly what hardware is in use.  Some of the 
>  fancier clocks have provision for GPS input.  I believe that both 
> Meinberg and Symmetricomm offer such.  I believe that both companies 
> offer driver software for these clocks allowing you to read and set them 
> and, perhaps, offering other functions as well.
Normally, I would just use a normal mainboard with a special oscillator, 
but that doesn't solve my problem. As far as I could find out, nobody so 
far modified the clock to be disciplined in NTP ...


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