Verified - ntpd ignores the year part of refclock timestamps

Hal Murray hmurray at
Thu Aug 31 04:24:18 UTC 2017

>> We could test fixup software by setting the system clock
>> ahead far enough to look like GPS had rolled over.

> What kind of fixup?  I looked long and hard at this problem in the context
> of GPSD.  I never found one that wasn't as bad - or worse - than relying on
> the sysrem clock date. 

I was thinking of testing the code to fixup a device that had rolled over and 
was now off by 1024 weeks.

Pretend the date is 1024 weeks in the future.  Now a good GPS device looks 
like it has rolled over and is giving bogus time.  Build ntpd with the pivot 
date set to 10 years in the future and run it with the system clock set to 15 
years in the future.  ntpd should fixup the GPS date and jump to 1024 weeks 
in the future.

These are my opinions.  I hate spam.

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