Hi On Aug 11, 2013, at 5:32 PM, Hal Murray <[email protected]> wrote:
> > [email protected] said: >> The issue with the fudge option is that you need to engage it at exactly the >> right point. Put another way, there's a period between it failing and your >> entering a fudge that the NTP server is down. > > Yup. But if you are running along and suddenly your GPS breaks, you might be > able to fix it by editing a config file and not needing to install any new > software or wait for the bug to get fixed. If you only "fix" it modulo 1024 when instructed, there isn't the same downside as a "change it all over the place" sort of solution. > >> With a couple lines of auto correct code in there, it would (essentially) >> never fail. If you are running a GPS, you enable the auto-correction and >> forget about it. My guess is that many GPS devices will eventually suffer >> from the wrap around > > Agreed. > > >> The only way they could avoid it would be some sort of external correction >> (like continuous firmware updates) or a "no reverse" on the year. Both >> approaches have their drawbacks….. > > There is another option that may be good-enough for some/many of us. That is > a way to tell the GPS unit the date. That *assumes* that the GPS firmware will accept a date as an input. The firmware would need to be able to do this. > > If a GPS device knows the rough date, it can get the right answer. > > Most GPS units have a battery and 32KHz clock to keep track of the time so > they can get started (much) quicker on power up: warm start vs cold start. > This isn't quite "no reverse", but it's pretty close. > > 1024 weeks is 20 years, so the batteries are probably old by the time this > gets interesting. But even an old tired battery might keep a clock ticking > for a few minutes/hours. That might cover rearranging cables or a > not-too-long power outage. > > But after the unit has been powered off too long (relative to the battery) or > after you replace the battery, you need some way to set the date. > > My Z3801A has been happy since I told it the date. I don't know if it has > been powered off since then. I should probably try the experiment. Z3805's and later have multiple receivers in them. Different firmware will / may fail at different times. Bob > > > > -- > These are my opinions. I hate spam. > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
