[time-nuts] NTP Clock suggestions?

[Kenton A. Hoover]

A useful reference to own: http://www.amazon.com/gp/aw/d/0521702380/ref=mw_dp_sim_ss1?pi=SL500_SY125  

--  
Kenton A. Hoover
kenton at nemersonhoover.org
+14158305843


On Monday, May 27, 2013 at 11:59, DaveH wrote:

> And don't get me started on Unix timekeeping...
>  
> Dave  
>  
> > -----Original Message-----
> > From: time-nuts-bounces at febo.com  
> > [mailto:time-nuts-bounces at febo.com] On Behalf Of Graham / KE9H
> > Sent: Monday, May 27, 2013 11:34
> > To: Discussion of precise time and frequency measurement
> > Subject: Re: [time-nuts] NTP Clock suggestions?
> >  
> > Miguel:
> >  
> > If you are going to build your own, I would recommend you start with
> > something like the Microchip PIC32 Ethernet Starter Kit. Comes
> > with a free GCC C/C++ compiler and an Ethernet stack.
> >  
> > I happened to have one for another project, that already had a
> > four line serial LCD display hooked to it, as well as a serial port
> > command line interface running
> >  
> > Since I was already familiar with the Ethernet Stack that comes with
> > the Starter Kit, all it took was turning on the SNTP function in the
> > stack, and writing about ten lines of C code to get it running.
> >  
> > One update of NTP sourced UTC Hours-Minutes-Seconds time on the
> > display per command line request. (Anything more complicated  
> > is left as
> > an exercise for the student.)
> >  
> > That was after about an hour's research to find out the time
> > format that NTP uses (seconds since Jan 1, 1900) and the
> > (different) time format that UNIX uses (seconds since Jan 1, 1970).
> > And how they both deal with leap-seconds since their
> > epoch started.
> >  
> > Another hour of time figuring out how to convert that to
> > today's Hours, minutes, and seconds. But that is easy,
> > once it (finally) sinks in how to work with an epoch.
> >  
> > Now, the real fun begins when you decide that you might
> > want to convert NTP or UNIX time to Day of Week, Month,
> > Calendar Year, Day of Year, Week of year, and
> > adjustments for local time zone, with daylight savings time.
> >  
> > That was worth about four hours research and going to bed with
> > a head-ache. Learned all about "Julian Day" and "Modified
> > Julian Day", which it turns out has nothing to do with
> > the Julian Calendar. (Did you know that time started at high noon
> > on January 1, 4713 BC. ?) Finally discovered a code snippet
> > in Tom Van Baak's "C" code repository that will do the
> > conversion. (Thanks, Tom.)
> >  
> > A pox upon leap years, un-leap centuries, re-leap 4th centuries,
> > Roman Numerals, modulus 7 weeks that do not align with the  
> > year boundary,
> > months with no regular modulus structure, and no year 0.
> >  
> > Who sold us this?
> >  
> > Makes you appreciate the decimal time "Star Date" system used  
> > on Startrek.
> >  
> > --- Graham
> >  
> > ==
> >  
> > On 5/27/2013 9:56 AM, Miguel Barbosa Gonçalves wrote:
> > > Hi Bob!
> > >  
> > > On 27 May 2013 14:56, Bob Camp <lists at rtty.us> wrote:
> > >  
> > > > Hi
> > > >  
> > > > Correct answer:
> > > >  
> > > > I don't think there is such a beast. Once you get away  
> > from the radio
> > > > controlled (WWVB etc) clocks the cost goes up quickly.
> > >  
> > > I don't understand why a microprocessor with an Ethernet  
> > >  
> >  
> > controller and a 7
> > > segment display would cost so much to manufacture... I  
> >  
> > think I'll build my
> > > own.
> > >  
> > >  
> > > > Also correct, but a bit of a joke answer:
> > > >  
> > > > Raspberry PI driving your television set. Alternatively  
> > make the Pi feed
> > > > control signals to a hacked normal clock.
> > >  
> > > Good joke :-) I imagine the electricity bill at the end of  
> > >  
> >  
> > the month.
> > >  
> > > I would like to have a clock sync with my super precise  
> > stratum 1 servers
> > > :-) what's the point in having them if I can see the time  
> >  
> > anywhere? :-)
> > >  
> > > Cheers,
> > > Miguel
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