Double summer time?

[Matthew Saltzman]

On Tue, 27 Mar 2007, Timothy Murphy wrote:

> Mogens Kjaer wrote:
>
> > > I've never really understood this question asked during 
installation:
> > > "Does your computer use UTC" (or something like that).
> > > How does one determine the answer?
> > >
> >
> > Look at the time in the BIOS.
>
> I looked in the BIOS,
> and there is nothing there to say if it is or is not using UTC.

Look at the hardware clock in the BIOS.  Is it set to your local time or 
to UTC (four hours ahead of EDT)?

>
> > You would use UTC=YES on a Linux-only machine, and UTC=NO
> > on a dualboot (Linux/Windows) machine.
>
> If that is a correct answer, then this simply confirms my view
> that this is a silly question to ask during installation.
>
> How is the user meant to determine the answer to the question?

The user decides what time to set the hardware clock to.  The two sensible 
choices are local time or UTC.  Then you answer the question according to 
your decision.

On a Linux-only machine, there is no reason not to set your hardware clock 
to anything but UTC.

On a dual-boot machine, you need to be aware that Windows always assumes 
your clock is in local time.  And if you keep the clock in local time, you 
have to watch out for the effect on the hardware clock of transitioning 
to/from DST.  The number of hours the clock jumps can range from zero to 
two, depending on the state of the machine at 2am on the change date and 
the sequence of boots afterward.

-- 
 		Matthew Saltzman

Clemson University Math Sciences
mjs AT clemson DOT edu
http://www.math.clemson.edu/~mjs