[ntp:questions] Re: NTP seems unsuitable for this application... what do you think?

John Seal sealj at indy.raytheon.com
Thu Dec 2 16:10:37 UTC 2004

Frederick Bruckman wrote:

> OK, now why should the two GPS hosts have the same time? What kind of
> backup can the second host be, if it isn't synced to anything? It seems
> to me that all you'd have to do to fix this configuration, is to run the
> special app on the backup host all the time.

You'd think so, but the local "none of us is as stupid as all of us" 
committee decided otherwise.  In other words, most of the engineers 
think running the special app all the time is obviously the right thing 
to do, but for a variety of reasons, we don't.  The previous version 
did, but the current one doesn't... sigh.

> There's no such thing as "right time and wrong date". The "time" is
> a count of the seconds since the start of the epoch, so if the date is
> wrong, the time is wrong.

That is true.  But our special program adjusts only the time, and not 
the date, so we often end up with what the users think is "right time 
and wrong date", even though it's really just a time that's wrong by an 
integer multiple of 24 hours!

> What difference would you expect it to make? The "ntpd" that ships with
> your OS probably doesn't support authentication anyway. (Authentication
> is new to NTP 4.2.0, IIRC.)

Whatever versions we have (Solaris 2.6 and Solaris 9 differ) are 
certainly documented in the man pages as supporting authentication.  It 
is Sun's xntpd, not ntpd.

Thanks for your response.

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