NTP - Standard/Daylight Savings Time change

[edwardp]

In March 2007, the U.S. (at least) will be changing the clocks ahead for Daylight Savings Time a couple of weeks earlier in March than at present and will change them back the first Sunday in November. Apparently, this change is going to be evaluated and a decision will be made whether to keep it, or go back to changing the clocks as it presently is (the last Sunday of March and October).

 

Because this is the first change in a number of years, is this something that NTP handles automatically when the time comes? Just curious...

 

 

[moved from Software by spinynorman]

Edited October 29, 2006 by edwardp

[ffi]

Don't know but I do know XP set my clock back 4 hours today instead of just one hour, which Mandriva correctly did...

[jaraeez]

Well you learn something everyday (hopefully!). I never knew that the USA also mess with time like us here in the UK. The reason (apparently) that we do it, is so the farmers have more light in the winter to do their thing (i'm guessing crops, milking the cows etc). Personally never like it, in the times the clocks go back it gets darker a lot quicker (3-4pm). Which in turn creates more road accidents involving children, more robberies. :(

 

Anyway Mandriva 2007 last night handled the UK time shift excellently... 1 min it was 1:50am then the next time i look it was 1:30am --very strange feeling-- ;)

[edwardp]

Mandriva correctly set the time this morning on both systems.

 

Windows XP, didn't.

Edited October 29, 2006 by edwardp

[scarecrow]

It's not advisable using NTP and/or UTC time settings on dualboot machines.

[edwardp]

It's not advisable using NTP and/or UTC time settings on dualboot machines.

 

Any particular reason for that?

 

Last year, when I used another Linux distro, I booted it up in XP first, which correctly changed the time. I then booted into Linux (with NTP enabled) and it also set the correct time. This year, I reversed it, Mandriva first, XP second. I also sent an e-mail with Mandriva and the time stamp correctly reflected -0500.

 

(What I plan to do eventually is get rid of Windows entirely and be 100% Linux, as long as there is an easy way to reformat the Windows partition and use it for Linux.)

Edited October 29, 2006 by edwardp

[ffi]

Well you learn something everyday (hopefully!). I never knew that the USA also mess with time like us here in the UK. The reason (apparently) that we do it, is so the farmers have more light in the winter to do their thing (i'm guessing crops, milking the cows etc). Personally never like it, in the times the clocks go back it gets darker a lot quicker (3-4pm). Which in turn creates more road accidents involving children, more robberies. :(

 

Anyway Mandriva 2007 last night handled the UK time shift excellently... 1 min it was 1:50am then the next time i look it was 1:30am --very strange feeling-- ;)

 

Winter time is the correct time (ie. winter time in the UK = GMT or UTC), summer time is GMT -1, it's so you have more light in summer evenings but I thinks summer time sucks big time, having to get up an hour earlier...

[ianw1974]

Mine didn't change in FC5, had to do it manually. Not sure how long I needed to wait for it to do it :P

[theYinYeti]

It's not advisable using NTP and/or UTC time settings on dualboot machines.

Any particular reason for that?

Unless things changed inside Windows, Windows stores local time in the hardware. At boot or runtime, if it detects that a change of time is necessary, then it changes it, and stores the new local time in the hardware.

Unix normally stores GMT/UTC time in the hardware. Local time is computed based on the timezone (TZ) and the GMT. This permits each user to have their own timezone preference (especially important in case of a server), and thus their own local time.

Thanksfully, Linux is now (since a long time) able to deal with Windows' way of storing time by doing the same.

 

Winter time is the correct time (ie. winter time in the UK = GMT or UTC), summer time is GMT -1

You're lucky! Here in France, we have no normal time!

At WW1 (IIRC, or is it WW2?), the German imposed their clock on the French, even though we are in the same geographical timezone as the English. Hence winter time is Germany's winter time: GMT+1 (one zone East of Greenwhich). In summer, we shift the time by one more hour, making that GMT+2; at the time this was decided (70'), it supposedly was to do savings on electric power.

 

Yves.

[neddie]

In March 2007, the U.S. (at least) will be changing the clocks ahead for Daylight Savings Time a couple of weeks earlier in March than at present and will change them back the first Sunday in November.

What a crazy idea. They're probably just trying to break currently working software and/or make it all even more complicated.

 

Why don't they just scrap the whole thing, rather than invent new inconsistent rules on when to switch and switch back?

[tyme]

What a crazy idea. They're probably just trying to break currently working software and/or make it all even more complicated.

Actually, it won't really break anything. This isn't the fictitious Y2K bug or anything, you can manually change it if you need to (OMG! Too much work!).

 

Why don't they just scrap the whole thing, rather than invent new inconsistent rules on when to switch and switch back?

Because it's actually useful to a large portion of the farmers which help produce a lot of the food that we eat? I dunno...that may be a good reason... :unsure: ...and that it saves energy, because we use lights less, that might be a good reason too... :unsure:

 

but ya, really they should just scrap it, because it's totally not useful.

[neddie]

you can manually change it if you need to (OMG! Too much work!).

Yeah I know you can change this manually but I was thinking of programs which convert to/from different local time zones. So at the moment it's more complicated than it needs to be, with the "should I convert to winter time or summer time" question, but as far as I know most places change from winter to summer on the same weekend. So I know that for example UK is one hour behind central Europe, and it doesn't matter whether it's winter or summer, the difference is always one hour. If for example UK decided to change a week earlier and change back an hour later, the difference between UK and central Europe would be sometimes one hour, sometimes two, and sometimes zero. So it just makes calculations more awkward, and confusion more likely, especially if you want to convert arbitrary timestamps, not just "now".

 

Because it's actually useful to a large portion of the farmers which help produce a lot of the food that we eat?

Wow, you really pulled that one out of thin air. How many farmers do you know who have told you that it's really useful to them to change their clocks? Personally I don't know any, but I'm damn sure their days are governed by when the cows get up and when the crops need mowing, not when the alarm clock goes off. I'd be very surprised if they gave two hoots about when or if the clocks go forward and back.

 

...and that it saves energy, because we use lights less, that might be a good reason too... :unsure:

OK, so now that the clocks have gone back, and the sun's going down at 5pm instead of 6pm, that means I use less energy now? Or you mean in midsummer, when the sun goes down at 9pm instead of 8pm, that uses less lighting? You still get the same length of daylight no matter how many hours you shift the clocks, so you use lighting for the other hours - as far as I can see that's still gonna be the same number too.

 

I just think it's outdated and unnecessarily complex. And if you're going to go to the effort of changing the system, I'd like to see it made simpler, not even more complex. Just my 2 cents.

[tyme]

...and that it saves energy, because we use lights less, that might be a good reason too... :unsure:

OK, so now that the clocks have gone back, and the sun's going down at 5pm instead of 6pm, that means I use less energy now? Or you mean in midsummer, when the sun goes down at 9pm instead of 8pm, that uses less lighting? You still get the same length of daylight no matter how many hours you shift the clocks, so you use lighting for the other hours - as far as I can see that's still gonna be the same number too.

hmmm...how about, no? Let's take, for example, sunrise and sunset times of the this past weekend:

 

Saturday:

Begin civil twilight 7:04 a.m.

Sunrise 7:32 a.m.

Sun transit 12:51 p.m.

Sunset 6:09 p.m.

End civil twilight 6:37 p.m.

 

The majority of people in the U.S. get up sometime after 7, but before 8 (during a work week). The sun is down around 6/6:30 (it's winter, so the sun starts setting earlier anyways). So, at 6:30, lights go on, and stay on until about 9:30/10 for most. Now, let's look at the day after:

 

Sunday:

Begin civil twilight 6:05 a.m.

Sunrise 6:33 a.m.

Sun transit 11:51 a.m.

Sunset 5:08 p.m.

End civil twilight 5:36 p.m.

 

The sun is up at 6. The majority of the U.S. is not up this early. The sun is down at 5:30, that's a full hour of extra time using light which amounts to a large chunk of energy when the entire U.S. is doing it.

 

The fact of the matter is that while you are correct in that the day has the same amount of light if we didn't have DST, you forget the fact that we don't change our habits based on when the sunrises and sets. We still get up at the same time and still get to bed at the same time, and so to save energy (which was actually the major reason for pushing to increase DST) you would want to have sunrise and sunset as close to the average time that people get up and go to bed. Seems like common sense to me ;)

[neddie]

Sounds like you just made a good argument to stick to summer time throughout the Winter too ;)

 

Now we're just on the switch but as the days get shorter, the people will be getting up before sunrise anyway, summer time or no. So that means by shifting the hour you're just adding to the amount of lighting required during the morning, and reducing that required in the evening (or the other way round) - more or less zero sum at the end of the day. And that for a lot of confusion and awkwardness.

 

Nyah, I'm just against it cos I keep getting caught out by it, arranging to meet people on the Sunday and at least one person always gets it wrong. And resetting all the (non-automatic) clocks around the house/car is a (yes, minor) pain.

[tyme]

Sounds like you just made a good argument to stick to summer time throughout the Winter too ;)

I know...

 

Now we're just on the switch but as the days get shorter, the people will be getting up before sunrise anyway, summer time or no.

Actually, in the dead of winter (December 30th) the sun will come up at 7 and twilight ends at 7:30, which matches up with the standard summer time and when most people get up ;)