Re: [time-nuts] Exact Time Mobile Phone Apps
> The timing must be very low level in the OS. Yes, and it can get a bit complicated. The desktop or server case is usually straightforward. Modern CPUs have a cycle count register. You can keep time with that if you know the clock frequency. There is another register on Intel architectures that counts at a known frequency. You can use that to calibrate the main clock that drives the cycle count register. Most PCs crystals are off far enough to be annoying, so one of the main things that ntpd does is reach into the kernel via a side door to tell the kernel the correction for the clock frequency. ntpd calls that drift. It's in log files and/or stored in a file so it can be used on reboot. ntpd can be good enough that you can use the drift as a thermometer. Things get interesting when you want to change the clock frequency to save power. I think some of the early cycle-counter implementations counted actual CPU cycles. I think modern chips count at a fixed rate that may not be the same as the CPU clock frequency. If you want to save more power, you can turn off the CPU clock. Laptops do this when you close the lid. Phones do it on a much finer grain. Then you have to set the clock when you turn the CPU clock back on. I'm not sure of the details in this area. Most systems have a battery backed clock running off a 32 KHz crystal. Typically, they can only be read to a granularity of 1 second. And they aren't drift-corrected, ... -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Exact Time Mobile Phone Apps
My network time is off by as much as 0.7 seconds. My phone isn't rooted, so I can't use the sync feature. Needless to say, this app has made me cranky! FWIW, using the GPS has no effect on the accuracy. Fortunately the VPN has no effect either. The timing must be very low level in the OS. On Sun, 2 Sep 2018 10:53:29 -0500 Ryan Stoner wrote: > I haven't seen that app in a long time! I got them to add the option > to include a custom NTP server. Great people! > > On my Android phone I use ClockSync < > https://play.google.com/store/apps/details?id=ru.org.amip.ClockSync>. > It has a ton of features especially if your phone is rooted. > > > > -- > Ryan Stoner > > On Sun, Sep 2, 2018, 08:08 D. Resor wrote: > > > I believe someone mentioned a cell phone "time" app. This is an > > image of the one I use for my iPhone. It is Emerald Sequoia. > > > > It queries correct time requests from four different NTP servers > > then picks the one with the least amount of response delay I > > believe. > > > > Of course when I'm out setting the clock on a Carillon system it > > has to be "just" right, doesn't it? > > > > I have uploaded a couple screen captures here: > > > > http://hammondorganservice.com/downloads/images/Emerald-Sequoia.jpg > > http://hammondorganservice.com/downloads/images/Emerald-Sequoia2.jpg > > > > > > A description of how it works is here: > > > > https://emeraldsequoia.com/et/index.html > > > > > > > > > > Don Resor > > N6KAW > > ___ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and > follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Exact Time Mobile Phone Apps
I haven't seen that app in a long time! I got them to add the option to include a custom NTP server. Great people! On my Android phone I use ClockSync < https://play.google.com/store/apps/details?id=ru.org.amip.ClockSync>. It has a ton of features especially if your phone is rooted. -- Ryan Stoner On Sun, Sep 2, 2018, 08:08 D. Resor wrote: > I believe someone mentioned a cell phone "time" app. This is an image of > the one I use for my iPhone. It is Emerald Sequoia. > > It queries correct time requests from four different NTP servers then picks > the one with the least amount of response delay I believe. > > Of course when I'm out setting the clock on a Carillon system it has to be > "just" right, doesn't it? > > I have uploaded a couple screen captures here: > > http://hammondorganservice.com/downloads/images/Emerald-Sequoia.jpg > http://hammondorganservice.com/downloads/images/Emerald-Sequoia2.jpg > > > A description of how it works is here: > > https://emeraldsequoia.com/et/index.html > > > > > Don Resor > N6KAW > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Exact Time Mobile Phone Apps
I believe someone mentioned a cell phone "time" app. This is an image of the one I use for my iPhone. It is Emerald Sequoia. It queries correct time requests from four different NTP servers then picks the one with the least amount of response delay I believe. Of course when I'm out setting the clock on a Carillon system it has to be "just" right, doesn't it? I have uploaded a couple screen captures here: http://hammondorganservice.com/downloads/images/Emerald-Sequoia.jpg http://hammondorganservice.com/downloads/images/Emerald-Sequoia2.jpg A description of how it works is here: https://emeraldsequoia.com/et/index.html Don Resor N6KAW ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
