Re: How to read the RTC value?

William G. Unruh __| Canadian Institute for|____ Tel: +1(604)822-3273
Physics&Astronomy _|___ Advanced Research _|____ Fax: +1(604)822-5324
UBC, Vancouver,BC _|_ Program in Cosmology |____ [email protected]
Canada V6T 1Z1 ____|____ and Gravity ______|_    theory.physics.ubc.ca/

On Fri, 9 Aug 2024, Jan Claußen wrote:

> [CAUTION: Non-UBC Email]While chronyd is running with the rtcfile directive, timedatectl shows
> 
> $ timedatectl
>                Local time: Fri 2024-08-09 14:12:01 UTC
>            Universal time: Fri 2024-08-09 14:12:01 UTC
>                  RTC time: n/a
>                 Time zone: Universal (UTC, +0000)
> System clock synchronized: yes
>               NTP service: active
>           RTC in local TZ: no
> 
> When using chronyc's rtcdata command, you get
> 
> RTC ref time (GMT) : Sat May 30 07:25:56 2015
> Number of samples  : 10
> Number of runs     : 5
> Sample span period :  549
> RTC is fast by     :    -1.632736 seconds
> RTC gains time at  :  -107.623 ppm
> where
> 
> RTC ref time (GMT)
> This is the RTC reading the last time its error was measured.
> 
> so this is not the current RTC value either. How to read it out then without having to stop chronyd?

I am not sure what you mean. You have all the data you need to figure out what
the time is. You know what its time read, you know how slow/fast it is, You
even know how fast it gains or loses time
Why are you reading the rtc anyway. It is not terribly accurate. And when
chrony is running, it keeps the time of rtc open not allowing anything else to
read it. You run the system clock to get accurate time. rtc is ONLY useful for
giving the clock a starting time when chrony is started. It is not useful as a
clock unless you are happy with times to nearest second.

> 
>