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Re: Mark IV data off by one day
Tom,
Yes you can get "time data" from Internet public time servers
to your Windows PCs even if the Windows PC can't "see" the Internet.
It's a common problem with a comomon solution. Newer versions
of both Windows and Linux come with the software you need.
No time to write a book about it here but you want to set up
one or more Linux PCs are NTP Servers that use a few servers
out on the net as sources. As long as the LInux PC can see the 'net
at least a few times a day they will stay in sync with "true UTC"
to the sub-second level. WIth DSL they will stay sync'd to the
milisecond level. Fermi lab just happens to have a public access
NTP server as do many universities and RedHat.com has two. You
need to find about five.
Next to tell your Windows PCs to use the Linux PC(s) as NTP
server(s).
You can do this step by step, not all at once
If you have an interrest in Servos it's neat the way NTP works.
THe Internet has very wide and unpredictable transmition
delays, it even drops data and servers can crash and simply
be taken down but even over this unreliable conection NTP can
keep two clocks sync'd to under a millisecond
What you need is a rather robust NTP system on your local
network. Not hard to do and once done the clocks stay "dead
on" pretty much forever.
IF you want to go this route post questions to this list.
My suggestion is to pick two or more Linux PCs (but start with one)
and make it an NTP server, next add another and make the two PCs
"peers". With multiple peers on your local net time will remain very
stable even if your DSL goes down for days at a time and you
have to re-boot a few PCs. A three peer system is very robust.
Then you tell your MS Windows boxes to look at either of the three
"peers" and each Windows system will pick the "best" one of the
three thatis currently up and running.
--- David Gamble <dgamble1@bigpond.net.au> wrote:
> Tom,
> I would love to come by and help with your system, however it is a
> bit far
> from here (Melbourne) to Chicago and also I don't claim to be a
> computer
> expert!
>
> I have however just set a wireless net work that works well and makes
> life
> very easy, particularly downloading large files from the internet.I
> am using
> a D-Link 11g router connected to the cable modem, with WiFi cards in
> each
> remote computer. Each remote computer then has direct access to
> Internet.
> This would certainly solve the timing issue, and might also help in
> other
> areas.
>
> ----- Original Message -----
> From: "Thomas Droege" <tdroege2@earthlink.net>
> To: "David Gamble" <dgamble1@bigpond.net.au>; <tass@listserv.wwa.com>
> Sent: Monday, June 07, 2004 10:31 AM
> Subject: Re: Mark IV data off by one day
>
>
> > David,
> >
> > Thank you very much for the information. I would do this if I
> could. The
> > problem is that the computers that run the telescopes can't get to
> the
> > internet evey though they can be read by the linux computers that
> can get
> > to the internet. I am sure that one of you computer experts could
> solve
> > this. But I can't. My plan is to get everything on linux in one
> > consistent network, and then I will be able to do this. All the
> computers
> > are on one network, but some directions of communications work,
> others do
> > not. So I am stuck with reading time from one of the computers
> that can
> > get to the net, or from a GPS receiver, and then setting my watch
> and then
> > going from computer to computer to set the time. I would offer to
> put
> > someone up to come by and straighten out the mess but I am after
> the long
> > term linux solution.
> >
> > Tom droege
> >
> >
> > > [Original Message]
> > > From: David Gamble <dgamble1@bigpond.net.au>
> > > To: <tdroege2@earthlink.net>; <tass@listserv.wwa.com>
> > > Date: 6/7/2004 2:56:04 PM
> > > Subject: Re: Mark IV data off by one day
> > >
> > > Hi Tom,
> > >
> > > It is possible to set Windows time using either a GPS in NMEA
> mode or
> > using
> > > one of the internet time servers such as atomic clock
> > > http://www.worldtimeserver.com/atomic-clock/ or NTIS
> > > http://www.boulder.nist.gov/timefreq/service/its.htm You could
> set these
> > up
> > > to run automatically on start up, or update periodically.
> > >
> > >
> > > ----- Original Message -----
> > > From: "Thomas Droege" <tdroege2@earthlink.net>
> > > To: "Man, Stupendous" <richmond@stupendous.cis.rit.edu>;
> > > <tass@listserv.wwa.com>
> > > Cc: <mwrsps@rit.edu>
> > > Sent: Monday, June 07, 2004 3:07 AM
> > > Subject: RE: Mark IV data off by one day
> > >
> > >
> > > > The clocks are set by hand, and there is always the possibility
> that I
> > > > could set them one day off. I don't always set them every
> night if
> they
> > > > are tracking the GPS well, so the tendency is to run several
> nights in
> a
> > > > row with the same clock setting.
> > > >
> > >
> > >
> >
> >
> >
> >
>
>
>
=====
Chris Albertson
Home: 310-376-1029 chrisalbertson90278@yahoo.com
Cell: 310-990-7550
Office: 310-336-5189 Christopher.J.Albertson@aero.org
KG6OMK
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