Re: Spring forward
At 12:15 PM 4/2/00, Adam Di Carlo wrote:
Ross Boylan <RossBoylan@stanfordalumni.org> writes:
> Now that the installation option to use the hardware clock as the local
> time is working, I wonder how this handles changes to clocks from daylight
> savings time.
Unix knows the hwclock is UTC and ajusts based on your timezone setting.
Right. It's the localtime setting that might be dicey.
> In the MS world there is an option about whether the system
> should adjust the clock for daylight savings. Perhaps such a question
> should be added to the install process?
No. The issue is simple:
unix (by default) expects hwclock to be UTC, unless you say otherwise
windows expects the hardware clock to be localtime
Thus on dual boot boxes you should set hwclock to localtime.
The tz issue raises no new issues.
I still think it does (or might). Here's why. If I sometimes boot
MS-Windows (MSW from now on) then I need to set GNU/Linux to use local
time. If I'm using local time, somebody needs to reset the hardware clock
when daylight savings starts or stops (this is an inference I make from the
need to have MSW do this).
MSW mostly: I let MSW reset the hardware clock, and things are fine when I
boot into GNU. (As long as I don't start it before MSW when the time zone
changes).
GNU mostly: Then I need GNU/Linux to reset the hardware clock.
So I have two cases where I use local time. In one case I simply take the
hardware time as right; in the other, I may want to adjust it.
So I think we need to ask which of these behaviors to follow. Of course,
that assumes the time zone machinery can support both.
> Also, I'm wondering what my computer will do tomorrow, when the clocks
here
> go 1 hour forward (US).
Assuming your tz setting is right, Unix does fine.
Well, I started NT and it has the right time. If Linux just reads it in,
it will be right. As I recall, my tz was PST/PDT (that is one choice
covers both daylight and standard time--as is always the case, I think).
A few years ago I was in Indiana, USA, which had the dubious distinction of
having 3 time zones (or perhaps I should say time regimes, since the only
zones were eastern and central times) in the same state: near Chicago it
followed Chicago time. In the south it followed Louisville (?) time. And
then some parts of the state never changed the clocks, so they were in
Central time part of the year and Eastern time the rest.
Indiana also almost passed legislation declaring the value of pi was 3, to
make computations easier. Supposedly it only failed because a math
professor happened to be in the visitors gallery of the state
legislature. At least, that's the story I heard.
But I digress.
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