Re: [gpsd-dev] GPS week wraparound

[Eric S. Raymond]

Hal Murray <address@hidden>:
> 
> address@hidden said:
> > The combination of PPS with NTP time should be reliable
> > regardless of what the local system clock gets up to.
> 
> > I left out my worries about bufferbloat-induced NTP clock skew...
> 
> It's probably worth mentioning that you are assuming buffer bloat and friends 
> are not causing troubles.

Yeah, I decided that after replying.  That 'graph now reads:

  However, none of these caveats affect the usefulness of PPS, which 
  tells us top of second to 50ns accuracy and can be made to condition a
  local NTP instance that does *not* rely on the system clock. The 
  combination of PPS with NTP time should be reliable regardless of
  what the local system clock gets up to. That is, unless NTP clock
  skew goes over 1 second, but this is unlikely to ever happen - and
  if it does the reasons will have nothing to do with GPS idiosyncracies.

Didn't seem like the place to go into the technicalia of bufferbloat.
-- 
                <a href="http://www.catb.org/~esr/";>Eric S. Raymond</a>