Re: Daylight savings testing

[Derek Y-E]

Hi Warren and WAMUG folks.

The short answers to your questions:
1). Your clock didn't change back, because your daylight savings  
testing range was too small.
2). IMHO, Apple have decided to keep the naming of time zones simple,  
and uncomplicated. Hence, they have chosen to not change the time- 
zone name, during DS. (Just my opinion though).


The long answer (to answer 1)...

Firstly to clarify... My previous daylight-savings tests worked fine  
for me...  The clock automatically dialed back EXACTLY when it  
should. I was 100% happy with the results (as posted Feb 21, 2007).  
My test workstation was set for the 25th of March 2007, and I watched  
the clock automatically roll back. (I started my workstation with the  
time of 12.30am. It rolled itself back an hour, one second after the  
"second" 2:59.59am, to 2:00.00am. Which is 100% correct.) From my  
perspective, the Daylight Savings update is working PERFECTLY, and  
has been since I installed it.


Your most recent post suggests that you have also done a test "2  
hours" before the daylight savings change over. Your testing methods  
may have differed from mine, but these are my conclusions from a  
couple of quick tests that I've successfully done with DST:


a). 10 seconds isn't enough time for the computer to register  
daylight savings changes. To be exact, 1 hour + few seconds IS  
enough... I'll explain this in a moment.
b). It is recommended to have the Date/Time Preference pane 'saved'  
and CLOSED during your tests. Otherwise, the computer may think that  
you are still adjusting the current time.
c). Run your daylight savings tests WITHOUT a network time server set  
on your machine. (Impossible to test with one set really).
d). The LATEST time that you can set your Mac to, to test the  
daylight savings update, is 1.59am, on March 25, 2007. Any later than  
that, and your computer will decide that your computer is NOT in  
daylight savings mode (further explanation below).


My understanding about the daylight savings update is this: it  
appears to have a "safety" or "counting" mechanism built into the  
system, since the end of daylight savings has two "two o'clocks".  
Think about what happens on March 25th... At 2.00am WDST, it's the  
first "two o'clock". At 1 second after 2:59.59am WDST, it's now the  
second "two o'clock". But how will your Mac know, which 2:00 you're  
currently at? The first one? Or the second one?
(We're winding our clocks back, so we get an extra hour, hence we  
actually get to re-live the hour of 2am again).

--

To differentiate, there is probably a "counter" programmed into the  
updated time system... There will be logic programmed into the  
system. Something like:
"If the current date is any date before March 25th, and the time is  
before 1:59.59am, then, add one to the counter, to indicate the  
presence of daylight savings, since this person is located in Perth,  
Western Australia".


OK, your Mac knows it's now in daylight savings time in Perth.

The next major event happens ON the day of the daylight savings  
change-over... 1 second after 1:59.59am WDST. The logic will go  
something like this:
"Check if in daylight savings mode. Yep, I am (got that "1" in the  
DST counter). Check the time... Is it 1 second after 1:59.59am, on  
March 25, 2007? Yep. OK. I'm going to add '1' to a new counter called  
'first two o'clock'. And I'll let the time tick straight over to  
2:00.00am, WDST."


OK, your computer is in the first "two o'clock" hour range. Daylight  
savings is 1 hour away from ending. But all is still normal, and  
there is no clock-winding yet.


The next event happens at 1 second after 2:59.59am WDST. The logic  
will go something like this:
"Check if in daylight savings mode. Yep. Check if one 'two o'clock'  
has already passed. Yep. Check time is 2:59.59am on March 25, 2007.  
Yep. OK, this is it folks... It's time to leave daylight savings.   
Set 'daylight savings finished counter' to '1', and reset the other  
counters. Oh, and set the time back an hour, to the 2nd 'two o'clock'.


And that's it. Your computer just wound it's clock back 1 hour, and  
is now living in it's 2nd "two o'clock" for the day.

--

So, if you set your computer 2.00am or 2.59am on the 25th of March  
2007, you're going to MISS some of those events, and daylight savings  
isn't going to tick over.

Instead, try your tests again. In particular double-check:
-Your menu bar clock as the seconds displayed (helps see when the  
change-over is going to happen)

-You are in the Perth WA time zone
-You have your network time server setting disabled
-Your time is before 1.59am, Ma

Re: Daylight savings testing

[Mervyn & Giuliana Bond]

Has the lack of roll-back got something to do with it only being 2 March 2007?
Merv

At 11:46 AM +0900 2/3/07, Warren Jones wrote:

I think you've missed my point on this one Shay.
My point was: why didn't my clock roll back the second daylight 
saving should have finished (03:00 WDT 25 Mar)? And secondly, why 
does my time zone say WST instead of WDT?


Derek said that in his testing it too didn't roll back when it 
should but did within an hour.


I repeated my test and left it for quite a while (> 2h) and it still 
hadn't rolled back.


I'm aware of what you said about NTP (my sentence actually said the 
same thing as you) and I had made a very similar comment on this 
list to someone else previously.


cheers
woz

PS On further testing just now and using the date -u command to 
check for time differences from UTC, I see that If you set the clock 
to anything past 02:00 on 25 Mar, it assumes that DS has ended. So 
to do my test properly I assume I'd have to set the clock to 01:59, 
and wait 61 mins instead of setting it to 02:59 and waiting 1 
minute. So I'll therefore conclude that the end of DS will work as 
it should. But it would be nice if Apple displayed WDT when it 
should instead of always WST.



On 01/03/2007, at 10:36 PM, Shay Telfer wrote:


Warren wrote:
Anyway, to check the end of the DS, I disabled NTP and set my 
clock to 25 Mar 2007 02:59:50 and was hoping that in 10 secs the 
time would be 02:00:00. Instead it just rolls over to 03:00:00.


I would have expected the DS zone changes to be independent of the 
NTP activation.


Comments?


The Network Time Protocol (NTP) simply synchronises the computers 
idea of what UTC (ie Greenwich Mean Time) is. Applying Timezone 
changes to UTC to work out what the local computer's time is is 
left to each individual computer's OS. Thus not being connected to 
NTP shouldn't make any difference for purposes of testing the 
daylight savings changeover.


http://www.faqs.org/rfcs/rfc1305.html
http://www.ntp.org/



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Re: Daylight savings testing

[Warren Jones]

I think you've missed my point on this one Shay.
My point was: why didn't my clock roll back the second daylight  
saving should have finished (03:00 WDT 25 Mar)? And secondly, why  
does my time zone say WST instead of WDT?


Derek said that in his testing it too didn't roll back when it should  
but did within an hour.


I repeated my test and left it for quite a while (> 2h) and it still  
hadn't rolled back.


I'm aware of what you said about NTP (my sentence actually said the  
same thing as you) and I had made a very similar comment on this list  
to someone else previously.


cheers
woz

PS On further testing just now and using the date -u command to check  
for time differences from UTC, I see that If you set the clock to  
anything past 02:00 on 25 Mar, it assumes that DS has ended. So to do  
my test properly I assume I'd have to set the clock to 01:59, and  
wait 61 mins instead of setting it to 02:59 and waiting 1 minute. So  
I'll therefore conclude that the end of DS will work as it should.  
But it would be nice if Apple displayed WDT when it should instead of  
always WST.



On 01/03/2007, at 10:36 PM, Shay Telfer wrote:


Warren wrote:
Anyway, to check the end of the DS, I disabled NTP and set my  
clock to 25 Mar 2007 02:59:50 and was hoping that in 10 secs the  
time would be 02:00:00. Instead it just rolls over to 03:00:00.


I would have expected the DS zone changes to be independent of the  
NTP activation.


Comments?


The Network Time Protocol (NTP) simply synchronises the computers  
idea of what UTC (ie Greenwich Mean Time) is. Applying Timezone  
changes to UTC to work out what the local computer's time is is  
left to each individual computer's OS. Thus not being connected to  
NTP shouldn't make any difference for purposes of testing the  
daylight savings changeover.


http://www.faqs.org/rfcs/rfc1305.html
http://www.ntp.org/

Re: Daylight savings testing

[Shay Telfer]

Warren wrote:
Anyway, to check the end of the DS, I disabled NTP and set my clock 
to 25 Mar 2007 02:59:50 and was hoping that in 10 secs the time 
would be 02:00:00. Instead it just rolls over to 03:00:00.


I would have expected the DS zone changes to be independent of the 
NTP activation.


Comments?


The Network Time Protocol (NTP) simply synchronises the computers 
idea of what UTC (ie Greenwich Mean Time) is. Applying Timezone 
changes to UTC to work out what the local computer's time is is left 
to each individual computer's OS. Thus not being connected to NTP 
shouldn't make any difference for purposes of testing the daylight 
savings changeover.


http://www.faqs.org/rfcs/rfc1305.html
http://www.ntp.org/

Have fun,
Shay
--
=== Shay  Telfer 
 Perth, Western Australia   Technomancer  The love of liberty is the love
 Opinions for hire  [POQ] of others; the love of power is
 http://newtonslore.com/fnord the love of ourselves - Hazlitt

Re: Daylight Savings testing -> Give your Mac more time

[Derek Y-E]

Hi Warren and WAMUG Folks.

Your test is probably a little simple. Giving the computer only 10  
seconds worth of time in Daylight Savings may not be enough to  
trigger the event.

(DLS ends at 3.00am, 25/03/2007, and the clock should go back to 2.00am)

I set a workstation to 12.30am, 25/03/2007, and got it to announce  
(Date/Time Pref pane) the time every hour... At "2.00am" it announced  
2am. An hour later ("3.00am"), it announced 2am again, and the clock  
was back at 2am. So, the DLS change worked.


An hour later, the time was announced as 3.00am for the first time...  
I.e. Working as expected also.


So, try your test again. This time though, give your Mac just a  
little longer to do the change-over.


Cheers,
Derek

On 20/02/2007, at 6:02 AM, WAMUG Mailing List wrote:


From: Warren Jones <[EMAIL PROTECTED]>
Subject: Daylight savings testing
Date: Sun, 25 Mar 2007 03:12:49 +0800
X-Mailer: Apple Mail (2.752.2)

Hi all
Has anyone done some proper testing of the new patch released last  
week?


After applying the patch, and clicking on Perth instead of Tokyo I
get the right time with the NTP server on (the time zone still shows
WST not WDT ???).

Anyway, to check the end of the DS, I disabled NTP and set my clock
to 25 Mar 2007 02:59:50 and was hoping that in 10 secs the time would
be 02:00:00. Instead it just rolls over to 03:00:00.

I would have expected the DS zone changes to be independent of the
NTP activation.

Comments?

Daylight savings testing

[Warren Jones]

Hi all
Has anyone done some proper testing of the new patch released last week?

After applying the patch, and clicking on Perth instead of Tokyo I  
get the right time with the NTP server on (the time zone still shows  
WST not WDT ???).


Anyway, to check the end of the DS, I disabled NTP and set my clock  
to 25 Mar 2007 02:59:50 and was hoping that in 10 secs the time would  
be 02:00:00. Instead it just rolls over to 03:00:00.


I would have expected the DS zone changes to be independent of the  
NTP activation.


Comments?