Universal vs local time

[Roger Oberholtzer]

On Fri, 22 Aug 2003 13:55:48 -0500
"David A. Bandel" <david at pananix.com> wrote:

> On Fri, 22 Aug 2003 13:25:10 +0200
> Roger Oberholtzer <roger at opq.se> wrote:
> 
> > On Fri, 22 Aug 2003 05:31:52 -0500
> > "David A. Bandel" <david at pananix.com> wrote:
> > 
> > > On 21 Aug 2003 22:18:38 -0400
> > > burns <linux at burnsmacdonald.com> wrote:
> > > 
> > > > On Thu, 2003-08-21 at 20:55, Joel Hammer wrote:
> > > > > How can I tell if my linux box is running with the clock set to
> > > > > universal or local time?
> > > > 
> > > > 
> > > > 'uname -a' gives you the system time. It's pretty obvious from
> > > > that what time standard it is using (local or otherwise).
> > > 
> > > Huh??
> > > 
> > > The only think uname -a shows is the time the kernel was built based
> > > on the system time of the system it was built on (which may not even
> > > be the system it was running on).  If you can ascertain anything
> > > about the hardware clock on the system from that, Sherlock, I'd like
> > > to know how.
> > 
> > Look at /etc/sysconfig/clock
> 
> and this has what to do with uname?

Nothing at all. The uname idea was not mine. Read Joel's original question
to see why I answered (correctly, I think) as I did.

/etc/sysconfig/clock is the relevant file. At least on SuSE, Gentoo (I
think) and Caldera. Don't know about others, and Joel was not specific in
the OS.

The real question is not what your clock is running at, but what the linux
system thinks it is running at.

> uname reads some parameters from the running kernel to provide you
> kernel type, kernel version, hostname the kernel was built on,
> architecture the kernel was built for, time and date (according to the
> system and the letting of /etc/localtime), and a few other parameters.
> 
> As for hwclock, some systems seem to ignore hwclock's -s (--set)
> parameter (as well as the --systohc argument).  I believe that's the
> fault of some compile-time options.

But you can still read the hardware time no matter what. If it differs from
what date tells you then I bet you are running a system that thinks the
clock is GMT.

> 
> > 
> > On SuSE mine is:
> > 
> > 	# Set to "-u" if your system clock is set to UTC, and to
> > 	# "--localtime" if your clock runs that way.
> > 	HWCLOCK="-u"
> > 
> > On Caldera it is:
> > 
> > 	CLOCKMODE=GMT
> > 
> > On SuSE, the option is really an option to the 'hwclock' command. I
> > don't see how you can get the current setting, unless you compare the
> > time from'hwclock --show' with that of 'date'. If they are off by
> > longer than the time it takes to run the two commands, then the
> > hardware clock is probably GMT.
> > 
> > That is all I have.
> 
> Ciao,
> 
> David A. Bandel
> -- 
> Focus on the dream, not the competition.
> 		Nemesis Racing Team motto
> GPG key autoresponder:  mailto:david_key at pananix.com
> 


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