[ntp:questions] nmea and initial large offset

Rob nomail at example.com
Sat May 8 07:40:24 UTC 2010


Richard B. Gilbert <rgilbert88 at comcast.net> wrote:
> The clock CHIP is not the problem.  The problem is that the quartz 
> crystal that provides the "tick" is usually one that failed quality 
> control at a wristwatch factory.

The issue under discussion is not the accuracy of the clock, but the
"fact" that it does not provide the year, only month/day/h/m/s.

I don't know about a chip that does not provide the year, but probably
it existed in some obscure computer more than 20 years ago.

I know the chip used in early PCs had only 2 year digits and thus could
not provide the century information, but I consider this a non-problem
as it can be easily worked around by having some threshold value above
which the year is considered in the past century (e.g. 80).

Defending silly algorithms in code with limitations in old hardware no
longer in use in running systems seems a bit silly to me.

But I often recognize a pattern where people who operate ntpd in different
environments than the one envisioned by the author get turned away when
suggesting changes.
We all know the discussions about systems not running 24h/day, systems
with instability related to temperature that changes over a day/night
pattern, arbitrary nonconfigrable limits on clock drift, initial clock
offset etc.




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