On 07/12/2020 10:13, Adam Funk wrote:
> Just out of curiosity, what significant benefits do you get from the
> RTC?  I have NTP running on mine, and the only anomaly I notice is
> this sort of thing in the `last` output:
>
> reboot   system boot  5.4.79-v7l+      Thu Jan  1 01:00   still running
>
> although `uptime` is correct and I can't find any '1970' or 'Jan' in
> any of the greppable log files.

You shouldn't see any 1970's on reboot. Raspian saves the current value
of the clock every 15 minutes or so. When you reboot it uses this saved
time until it gets updated from ntp.

You may notice the syslog doing this

1720 Some stuff happening  # the last log entry before rebooting
1715 Rebooting             # Reboot using last saved time
...
1715 Getting RTC
1722 More startup          # The time has been updated
...
1723 Finished rebooting

The jumping of the time backwards and forwards can be a little
confusing, but it is possible to work out what is happening.

The advantage of a real time clock chip is this is avoided and the
reboot time will be more accurate.

I wouldn't use a GPS clock for reboot, as may take too long to give a
reading, it is more suited to keeping accurate time once the machine is
up and running - as long as it has a good view of the sky.

---drukc

--- SoupGate-Win32 v1.05