On 2014-11-03 04:16, Fraser Bell wrote:
> However, for the past several years, I have noticed that when I set the
> Hardware clock to Local Time, the time changes are automatically taking
> place, in spite of the warning.
>
> (This is a good thing, of course, not complaining. 
)
It doesn’t mean what you think it means, though
> I just thought I would mention this, so Users do not make their choice
> between UTC and Local Time solely on that (apparent) misinformation.
The information given at install is correct >:-)
But too short. Or typically terse.
I’ll explain.
Say you halt the machine on the night of 2014-10-25, and boot it on the
morning of 2014-10-26. That was daylight change day, at least in Spain.
Say that your CMOS was set to /local/ time.
Say you do not have internet at all.
Well, then I say 
] that your machine will be off by one hour on
the morning boot.
/But/ if you have internet and you enabled ntp, aka internet time in
other oses parlance, your machine will inquire the correct time from
internet and correct itself, maybe before you have time to notice. It is
possible that the event is logged.
That’s the meaning of the paragraph during install and perhaps on
release notes. Not what you thought 
It also has other meanings.
Like that Windows will change the time in the CMOS an hour in the
/correct/ direction when it boots that day, even if Linux changed it
earlier. And if instead you boot Linux later than Windows, it will not
say “Hey! Today it is daylight change day! Let’s change the hour.” Which
Windows had already done, resulting in a double change. The openSUSE
devs have finally given up in outsmarting Windows, and just leave the
clock alone, change not the hour.
Of course, if the machine has an external clock reference, like
Internet, it will indeed correct the time. It just doesn’t change it on
“its own” (via openSUSE boot scripts).
On the other hand, if the machine is running at 3:00 AM, which is the
hour that the change is done in Spain, you will see how the clock is
adjusted automatically, by the kernel:
> <3.6> 2014-10-26 00:58:01 Telcontar systemd 1 - - Starting Session 461 of user news.
> <3.6> 2014-10-26 01:00:01 Telcontar systemd 1 - - Starting Session 462 of user root.
> <3.6> 2014-10-26 01:58:01 Telcontar systemd 1 - - Starting Session 488 of user news.
> <3.6> 2014-10-26 02:00:01 Telcontar systemd 1 - - Starting Session 489 of user root.
....
> <3.6> 2014-10-26 02:55:01 Telcontar systemd 1 - - Starting Session 514 of user news.
> <3.6> 2014-10-26 02:58:01 Telcontar systemd 1 - - Starting Session 515 of user news.
> <3.6> 2014-10-26 02:00:01 Telcontar systemd 1 - - Starting Session 516 of user cer.
> <3.6> 2014-10-26 02:00:01 Telcontar systemd 1 - - Starting Session 517 of user root.
> <3.6> 2014-10-26 02:00:01 Telcontar systemd 1 - - Starting Session 518 of user cer.
> <3.6> 2014-10-26 02:03:01 Telcontar systemd 1 - - Starting Session 519 of user news.
> <3.6> 2014-10-26 02:05:01 Telcontar systemd 1 - - Starting Session 520 of user news.
....
> <3.6> 2014-10-26 02:55:01 Telcontar systemd 1 - - Starting Session 541 of user news.
> <3.6> 2014-10-26 02:58:01 Telcontar systemd 1 - - Starting Session 542 of user news.
> <3.6> 2014-10-26 03:00:01 Telcontar systemd 1 - - Starting Session 543 of user root.
> <3.6> 2014-10-26 03:00:01 Telcontar systemd 1 - - Starting Session 544 of user cer.
Do you see how the clock goes back at 3:00? from 2:59 it goes back to
2:00 instead of 3:00 just once. It is curious to see if you are actually
watching the display.
(yes, you can reproduce it in a virtual system and check, with tricks to
isolate the time)
–
Cheers / Saludos,
Carlos E. R.
(from 13.1 x86_64 “Bottle” at Telcontar)