[ntp:questions] Local Time

Kevin Oberman oberman at es.net
Wed Mar 14 19:05:37 UTC 2007


> From: "Wolfgang S. Rupprecht" <wolfgang.rupprecht+gnus200703 at gmail.com>
> Date: Wed, 14 Mar 2007 11:18:23 -0700
> Sender: questions-bounces+oberman=es.net at lists.ntp.isc.org
> 
> 
> > Most systems keep internal time in UTC and I am hard pressed to think
> > of any recent system that doesn't.
> 
> Just for the record.
> 
> Unfortunately linux (at least the fedora flavor of it) has a bit or
> wrong-think creeping in, in this regard.  The clock chip defaults to
> local time and the kernel knows the TZ offfset and has some
> compensation.  Uhg.
> 
> Obviously, for the sake of keeping sane, I've elected to have my
> system (virtually) located in England.

If Fedora keeps time anything like BSD, there is a flag that indicates
that the hardware clock is set to local time and not UTC. But the kernel
still operates on UTC. It simply uses the time zone information to set
the hardware clock. (In FreeBSD it is dependent on the existence of
/etc/wall_cmos_clock on the system.)

But the system still uses UTC for everything except reading and writing
the hardware clock and the offsets used are still controlled by the zone
files.

This was done for dual boot systems which need to boot Windows which
sets the hardware clock to local time. I have this only for my laptop
(which is dual boot) and all Unix-only systems have the hardware clock
set to UTC.
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at es.net			Phone: +1 510 486-8634
Key fingerprint:059B 2DDF 031C 9BA3 14A4  EADA 927D EBB3 987B 3751
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