On 01/02/2017 05:55, sean wrote:
[]
Hi Dave,
Thank you for the reply. I found your website about 3 weeks ago and got
the urge to checkout GPS devices, like the GPS18, Raspberry pi options,
etc. Thank you for it and all of the graphs. You certainly have many Pis
keep track of the time! I don't recall, are you apart of the NTP Pool?
I found your website to have a wealth of great information that's quite
well compiled and thoughout. I hope your health is much better this
year and that you're on the road to recovery.
Primarily I run FreeBSD and was surprised to learn that it can have
better precision than Linux, although the articles I read were FreeBSD
8.0 era. Do you find FreeBSD generic kernel comparable with Linux? From
what it sounds like, a Raspberry Pi with the device below will give me
"pretty accurate" (my words) time, which I can use to sync my devices in
my home.
http://www.satsignal.eu/mrtg/performance_ntp.php
For the Raspberry Pi:
https://store.uputronics.com/index.php?route=product/product&product_id=81
That's pretty well priced, cheaper than the Garmin
In terms of installations, I think that NTP will have by far the
greatest number, and of the three you listed, only NTP runs on Windows.
Well I don't really have any Windows installations, but I will keep NTP
in mind when I want to run time syncing on Windows. As an aside, what
does Windows natively use to keep time and sync?
Thanks,
Sean
Sean,
Thanks for your comments - much of the Web site is comprised of my own
notes to remind me what to do next time! Still waiting for one minor
operation, and then to see if (or should it be when?) the Crohn's returns.
Unfortunately I can't be part of the pool as my ISP doesn't offer static
addresses.
I don't know whether FreeBSD is better than Linux any more, others will
need to answer that. My FreeBSD box refused to update from FreeBSD 7 to
FreeBSD 8, so I stuck Linux on it in desperation!
Another low-cost device is the Sure evaluation board:
http://www.satsignal.eu/ntp/Sure-GPS.htm
http://www.ebay.com/itm/SKG16A-Bluetooth-RS232-USB-UART-GPS-Module-Demo-Board-/230844194302
Windows uses NTP but not with the reference implementation, so of
unknown quality, and not manageable in the same way. It used to be
lousy, and I've not tested since then.
What will be good enough depends on your needs. The lowest cost might
be the Sure board attached to an existing FreeBSD box, running 24 x 7
and in as stable a thermal environment as necessary. Both the Raspberry
Pi and BeagleBone Black are low-power devices and therefore low-cost to
run 24 x 7, with the BBB having a slightly better Ethernet
implementation if you need to get down to the tens of microseconds
level, but with the Raspberry Pi have a much wider support even though
it might offer (approx) fifties of microseconds. Judge for yourself here:
http://www.satsignal.eu/ntp/BBB-vs-RPi.html
If you already have an RPi doing something, adding a NTP server to its
tasks will make little extra load for an environment with a thousand or
more clients....
--
Cheers,
David
Web: http://www.satsignal.eu
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