[time-nuts] This list

John Ackermann N8UR jra at febo.com
Tue Jul 19 18:33:18 EDT 2005


Joseph Gray wrote:

> I have noticed that this list seems to send emails out of sequence. I
> have seen other instances of this, but the two messages I just sent in
> response to the HP 5060A query arrived in reverse order and show time
> stamps 30 minutes apart. I sent my replies to the list about one
> minute apart.
>
> Maybe the list server needs a new Rolex?

I'm not sure why messages get out of sequence. I think it's the mail
queue process -- if for some reason message 1 is delayed (ie, your
mailhost is temporarily unreachable) it may be deferred for X minutes
before trying again.  If another message comes along after the temporary
problem clears, it may go directly while the earlier message is still
being held.  That's a theory, anyway -- I haven't dug into it as the
delays haven't been a problem (and they're not unique here -- I very
frequently see this from the NTP mailing list server, which uses the
same Mailman listserve software as I do).

Re the Rolex -- I feel compelled to let the list know that all the
servers at febo.com run ntp, and look to my (at the moment) two stratum
1 servers -- one gets its time from a Z3801A GPSDO, while the other uses
both a Z3801A and a Spectracom WWVB receiver.  I just checked, and the
mailserver machine is currently offset about 0.3ms from those two sources.

(When I get back from vacation, my first project is reconfiguring the
NTP setup.  I just acquired a stack of cheap 1U servers, and three of
them -- named tick, tock, and toe -- will be running FreeBSD, each with
one reference clock initially.  After some software tweaking, I hope to
be able to add the 1pps from my two Cesiums to the mix, so I'll have
five reference clocks driving the time suite.)

John





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