[time-nuts] PC clock comparison software?

[Charles S. Osborne]

Lots of good info as always from this list.

I probably should mention what some of these PCs are doing.

Someone asked about the telescope control PCs. The 26m dishes have their own
dedicated GPS receivers for their local time standards. Those do the
celestial navigation and tracking via their control PCs.

Our optical telescope control PCs are almost all on XP or Win2000. So NTP
should have them covered reasonably well. Test software would confirm how
well.

The PCs that tend to misbehave the most are Win98se Pentium 100 ~ 400 MHz.
They are doing a variety of menial tasks like: seismic data, solar flare
monitoring, meteor burst recording, VLF signal recording for Sudden
Ionospheric Disturbances, and cosmic ray montoring. They churn along at 4 ~
40 samples per second typically of constant data flow to the hard drive.
Every minute or so they may push a screen capture to our website.

Others with a somewhat higher workload are doing webcam or weather station
image pushes to our website once a minute.

For time/frequency we have two Z3816As and a Ball Efratom MRT free running
Rubidium frequency standard. I tweak it using an HP53131time interval
counter compared to the Z3816A. GPSCon V1.038 is the software running on a
Win98se box. I have a newer XP box I've been trying to move to for better
serving reasons. But it keeps turning itself off every night even though
we've tried to turn off power saving and automatic updates. Its on a UPS
with four 100AH batteries, plus four 7AH gel cells on float on the Z3816A
48vdc power side. The slightest power glitch still takes the XP computer
down even though its on the UPS. But the Win98se P166 plugged into the same
outlet strip on the same UPS weathers it all for months at a time without
rebooting.

The main network servers are Linux of one variety or another. Not sure what
the latest flavors are, but mostly Red Hat Linux Fedora Core I think.

The network glitches are probably power glitch related even though most
things are on UPSs. We're pretty far up in the mountains, so lightning and
AC supply side glitches are common. And the sheer size of the facility
induces surges from EMP transferred cable to cable on site too. The primary
fiber links are via 3Com ATM Core Builders with redundant fiber links. Its
mostly once things get out to the localized 8~24 port switches that latch up
occurs I think. Diagnostic code would help troubleshoot that since I could
see which branches failed when, and if they recover. Network loading is
minimal except from the main website server to the Internet via T1 ( soon
OC3, then that will be minimally loaded too except during distance learning
and video conferencing).

tnx,
Charles S. Osborne, K4CSO
Technical Director

Pisgah Astronomical Research Institute
1 PARI Drive, HC 73, Box 638
Rosman, NC 28772-9614
http://www.pari.edu
828-862-5813 direct
828-862-5554 main
828-862-5877 FAX
cosborne at pari.edu