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Re: What time is it, really?

On Thu, Aug 09, 2018 at 10:35:23AM -0400, Greg Wooledge wrote:
On Thu, Aug 09, 2018 at 07:19:46AM -0700, Fred wrote:
So I installed ntpdate as suggested but it is
not active yet.

Whoever suggested that is using outdated information.  Install ntp and
not ntpdate.

The current versions of the ntp package (since, like, Debian 6.x I think)
incorporate the one-time clock slamming feature of ntpdate, so you don't
need ntpdate at all.

If I ask google what time it is in Mesa AZ. the response agrees closely with
an "atomic" clock I have.  The computer clock is about 10 min. fast.

Once you've had ntp installed for several minutes (and possibly rebooted,
if your clock was particularly bad), you can query it with "ntpq -p" to
see how it's doing.

Unfortunately, the output format of ntpq -p isn't DOCUMENTED anywhere, so
it's a bit cryptic.  The most important thing to know, which is not stated
anywhere except word of mouth like this email, is that the "offset" column
is reporting milliseconds, not seconds.

Actually, quoting http://doc.ntp.org/current-stable/debug.html: "Note that, except for explicit calendar dates, times are in milliseconds and frequencies are in parts-per-million (PPM).

Additionally, from http://doc.ntp.org/current-stable/ntpq.html#rv (rv allows one to read the offset for a particular association directly), "Note that time values are represented in milliseconds and frequency values in parts-per-million (PPM)."

For more information, please reread.

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