On 14/10/2019 12:24, NY wrote:
> "druck"  wrote in message news:qno2oo$759$1@dont-email.me...
>
> On 09/10/2019 20:31, Dennis Lee Bieber wrote:
>> > I'd updated both 3B+, 4B2G, and 4B4G to the most recent Noobs
>> Raspbian > last week. Today I ran "sudo apt-get update/sudo apt-get
>> upgrade" on > systems (main item: an SSL update). While the second 3B+
>> was processing > the "upgrade" phase, I plugged in the 4B2G. I was
>> able to run the same > update/upgrade, shutdown, swap with the 4B4G,
>> update/upgrade (needed two > updates -- NTP had not synched the time
>> and it rejected a repository for
>
> The lack of a battery-backed (or even capacitor-backed) real-time clock
> is a nuisance if the Pi reboots and there isn't an internet connection
> by the time the Pi needs it - if it takes longer for the router to boot
> and establish a connection than it takes the Pi to boot. I run a
> weather-station recording package (Cumulus) on my Pi and occasionally
> after a power cut the Pi has booted up with the wrong time (eg 30 or so
> minutes in the past) so I've had readings every minute marked with the
> wrong time which leads to a graph that goes back in time (!) until NTP
> eventually syncs the Pi's clock (*). It happens so rarely that it's not
> worth devising my own external battery-backed RTC solution, but it's
> annoying when I have to go in and hand-modify the times in the log files
> and restart the software so it reads and displays them on its graphs.

I have killed and disabled the systemd service fake-hwclock.service
(systemd does a load/force at startup, which can screw the time
abominably) and then do "fake-hwclock load" at reboot (in /etc/cron.d/)
and run "/sbin/fake-hwclock save" as a root cron job every minute.

>
>> > being invalid [the R-Pi was using the last boot time, and the
>> repository > was dated five days in the future ]), and shutdown...
>> ALL BEFORE the > 3B+ finished its upgrade of the same files.
>> >
>> > Either that 3B+ has a very slow SD card, or a distinct speed
>> difference.
>
>> The Raspberry Pi 4's SD card reader is many times faster than on
>> previous models.
>
> Have you found that access to the system drive and swap area is affected
> by the slower SD access of the 3B+? I also use my 3B+ Pi as a PVR (a
> video recorder) and I was impressed that the software I use (TVHeadend)
> was able to write several overlapping programmes, including in HD, to
> the SD card without any apparent bottleneck. I only switched to
> recording to USB hard drive because I needed more space than on a 32 GB
> SD card.
>
>
> (*) Sometimes it has taken maybe 20-30 minutes before the timestamp of
> the weather readings is correct - I'm not sure whether it's NTP that is
> taking that long to set the system time correctly, or whether it's the
> weather-station software that isn't noticing that the system time has
> been corrected. Both times it's happened are when I haven't been around,
> so I've been able to look at the system time (eg using the date command)
> in the interim.



--

Chris Elvidge, England

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