[ntp:questions] Using different timebase for ntpd

Hal Murray hal-usenet at ip-64-139-1-69.sjc.megapath.net
Sat Apr 25 07:16:29 UTC 2009

>As mentioned in my other posting from today, my final goal is to run NTP 
>with hardware timestamp support to have a fair comparison to IEEE 1588 
>for my PhD. (I guess, there won't be much difference, concerning 
>accuracy) Unfortunately, I couldn't find any implementations (maybe 
>there is a good reason ...?) so I'm trying it on my own.
>I know how to get the timestamps from the network card into NTP but I 
>need the daemon to discipline the clock on the card to make it somehow 

Have you considered hacking the kernel rather than ntpd?

The idea is to implement the system clock in a corner of your FPGA.
When the system wants to know the time, it reads it from the FPGA.
You would have to implement the drift correction and something
for slewing the clock in the FPGA.  That doesn't sound like a hard
problem.  (I assume you are familiar with DDS.  You can pipeline
things as deep as you want.)

These are my opinions, not necessarily my employer's.  I hate spam.

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