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Re: system time has change while installing

On Wed, Jun 19, 2013 at 09:10:06AM +0100, Darac Marjal wrote:

> This isn't actually an error. But perhaps an issue with PC design. The
> internal clock of your PC stores a time and date, but it DOESN'T store
> which time zone you're in. All it stores is, for example, "20:20".

> When you install a new OS, it reads that time and must make one of two
> assumtions: Either the time is stored as local time (in which case no
> adjustment is necessary, but there may be issues when Daylight Saving
> Time comes into effect) or atomic time, UTC (in which case 8 hours must
> be added on before displaying the time to the user).

> There is no right or wrong answer to which method to use. Linux assumes
> the hardware uses UTC, Windows assumes it uses local time. Both can be
> configured to use either method
> (https://wiki.archlinux.org/index.php/Time#Time_standard) and it's best
> if they agree.

No, there is a right answer: use UTC for the system clock, always.  Using
local time means the value stored in the system clock *must be changed*
across daylight savings time boundaries, which is stupid.

The *only* argument for using local time in the system clock is so that the
time displayed in the timezone-ignorant BIOS will be correct.  But who looks
at the time in the BIOS anyway?

Steve Langasek                   Give me a lever long enough and a Free OS
Debian Developer                   to set it on, and I can move the world.
Ubuntu Developer                                    http://www.debian.org/
slangasek@ubuntu.com                                     vorlon@debian.org

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