OT: Will the changes to U.S. Daylight Savings Time cause the clock to be set incorrectly?

C

CDMAPoster

According to:

http://wwp.daylight-saving-time.com/usa/dst-2007.htm

a 2005 Energy Bill will cause the effective dates for Daylight Saving
Time in the U.S. to begin at 2 a.m. on the Second Sunday in March and
end at 2 a.m. on the First Sunday in November, beginning in 2007. Will
the automatic adjustment for DST in the various versions of Windows
cause the clock to be set incorrectly?

James A. Fortune
(e-mail address removed)
(e-mail address removed)
 
R

Rick B

This is an Access newsgroup. I'd suggest asking your question in a Windows
newsgroup.

I'm fairly certain that Windows will update their software to handle this,
though.
 
S

salad

According to:

http://wwp.daylight-saving-time.com/usa/dst-2007.htm

a 2005 Energy Bill will cause the effective dates for Daylight Saving
Time in the U.S. to begin at 2 a.m. on the Second Sunday in March and
end at 2 a.m. on the First Sunday in November, beginning in 2007. Will
the automatic adjustment for DST in the various versions of Windows
cause the clock to be set incorrectly?

James A. Fortune
(e-mail address removed)
(e-mail address removed)
I wouldn't know but I should think if you have up-to-date window patches
that will not be a problem.

I did read from a KB article the following "SUMMARY
Some system BIOS adjust the computers built-in real-time clock to
compensate for daylight savings time automatically. Windows NT can also
be configured to adjust for daylight savings time. If both the BIOS and
Windows NT adjust the close for daylight savings time, your clock will
be one hour off."

I gather that if it is a software update, it will work fine. If the
System bios is also used, you could have a problem
 
S

salad

salad said:
I wouldn't know but I should think if you have up-to-date window patches
that will not be a problem.

I did read from a KB article the following "SUMMARY
Some system BIOS adjust the computers built-in real-time clock to
compensate for daylight savings time automatically. Windows NT can also
be configured to adjust for daylight savings time. If both the BIOS and
Windows NT adjust the close for daylight savings time, your clock will
be one hour off."

I gather that if it is a software update, it will work fine. If the
System bios is also used, you could have a problem

I wonder how DST is handled for a state like AZ which has no DST.
 
S

Smartin

salad said:
I wonder how DST is handled for a state like AZ which has no DST.

There is a time zone specification in Windows special for AZ, and other
areas like east Indiana that do not observe DST. I presume those
settings cause the system to never adjust for DST (^:
 
S

Smartin

According to:

http://wwp.daylight-saving-time.com/usa/dst-2007.htm

a 2005 Energy Bill will cause the effective dates for Daylight Saving
Time in the U.S. to begin at 2 a.m. on the Second Sunday in March and
end at 2 a.m. on the First Sunday in November, beginning in 2007. Will
the automatic adjustment for DST in the various versions of Windows
cause the clock to be set incorrectly?

James A. Fortune
(e-mail address removed)
(e-mail address removed)

Curious question. Surely other systems have a built-in algorithm to
handle DST adjustments also. The impact of changing the DST "rule" could
be interesting.

However, since my little ol' PC synchronizes with time on the net every
week or so, should I worry?
 
D

David W. Fenton

(e-mail address removed) wrote in
According to:

http://wwp.daylight-saving-time.com/usa/dst-2007.htm

a 2005 Energy Bill will cause the effective dates for Daylight
Saving Time in the U.S. to begin at 2 a.m. on the Second Sunday in
March and end at 2 a.m. on the First Sunday in November, beginning
in 2007. Will the automatic adjustment for DST in the various
versions of Windows cause the clock to be set incorrectly?

Don't you have the time service running on all your computers so
it's going to update correctly, anyway?
 
J

James A. Fortune

Smartin said:
Curious question. Surely other systems have a built-in algorithm to
handle DST adjustments also. The impact of changing the DST "rule" could
be interesting.

However, since my little ol' PC synchronizes with time on the net every
week or so, should I worry?

You and David have a great idea. You only need to worry about your data
for a maximum of four weeks per year :), the week between the false
changing of the clock until the synchronization, the week between the
failure to change the clock and the synchronization, and the two weeks
for the vice-versa case.

James A. Fortune
(e-mail address removed)
 
T

Terry Kreft

Suck it and See?

Change the clock on your PC to just before the effective date/time and see
what happens after the clock ticks over.
 
G

Gord

Don't you have the time service running on all your computers so
it's going to update correctly, anyway?

The timezone offset on the client machine still has to be correct. If
my machine thinks that it is on EST (-0500) when it should actually be
on EDT (-0400) then it will still be "off" by an hour after
synchronizing with an NTP server.

For example, my machine would display 10:21 (EST) when it was really
11:21 (EDT). Both times are "correct" in that they correspond to 15:21
UTC, but it's the localized time that is at issue here.
 
L

Lyle Fairfield

Terry said:
Suck it and See?

Change the clock on your PC to just before the effective date/time and see
what happens after the clock ticks over.

I !!!!!think!!!!! that unless something changes these registry settings
(below) on my computer then the changes will be made in the first week
of April and the last week of October.

Will something change them automatically? I'd guess that MS or Nist or
someone else will send out a reg file or patch we can import that will
do this.

If not they can be edited manually in regedit (maybe not a good idea
for the not-so-brave)
or with
Private Declare Function SetTimeZoneInformation _
Lib "kernel32" _
(lpTimeZoneInformation As TIME_ZONE_INFORMATION) _
As Long
ot they can be exported, edited in notepad or similar and them imported
back.

Perhpas they are modified by time updates but doubt it. Messing with
people's registry settings is unlikely to win friends and influence
people. Well, of course if you are MS, obviously you don't care about
that.

But what are they? They're supposed????to be SystemTime Types
Private Type SYSTEMTIME
wYear As Integer
wMonth As Integer
wDayOfWeek As Integer
wDay As Integer
wHour As Integer
wMinute As Integer
wSecond As Integer
wMilliseconds As Integer
End Type

but they don't look like that to me. Perhaps Windows cheats on the
storage and just stores the ordinal of the Sunday with respect to month
in place of day of week and hour in place of day (day of month).

Key Name:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\TimeZoneInformation
Class Name: <NO CLASS>
Last Write Time: 2006-04-02 - 05:38
Value 0
Name: Bias
Type: REG_DWORD
Data: 0x12c

Value 1
Name: StandardName
Type: REG_SZ
Data: Eastern Standard Time

Value 2
Name: StandardBias
Type: REG_DWORD
Data: 0x0

Value 3
Name: StandardStart
Type: REG_BINARY
Data:
00000000 00 00 0a 00 05 00 02 00 - 00 00 00 00 00 00 00 00
.................


Value 4
Name: DaylightName
Type: REG_SZ
Data: Eastern Daylight Time

Value 5
Name: DaylightBias
Type: REG_DWORD
Data: 0xffffffc4

Value 6
Name: DaylightStart
Type: REG_BINARY
Data:
00000000 00 00 04 00 01 00 02 00 - 00 00 00 00 00 00 00 00
.................


Value 7
Name: ActiveTimeBias
Type: REG_DWORD
Data: 0xf0

ramble ... ramble ... ramble
 
P

(PeteCresswell)

Per David W. Fenton:
Don't you have the time service running on all your computers so
it's going to update correctly, anyway?

Any idea what that service is called?

I popped MyComputer|Manage|Services And Applications|Services and didn't see
anything called "Time".

Windows XP Pro.
 
T

Terry Kreft

Suck it and See !

<g>

--

Terry Kreft


Lyle Fairfield said:
I !!!!!think!!!!! that unless something changes these registry settings
(below) on my computer then the changes will be made in the first week
of April and the last week of October.

Will something change them automatically? I'd guess that MS or Nist or
someone else will send out a reg file or patch we can import that will
do this.

If not they can be edited manually in regedit (maybe not a good idea
for the not-so-brave)
or with
Private Declare Function SetTimeZoneInformation _
Lib "kernel32" _
(lpTimeZoneInformation As TIME_ZONE_INFORMATION) _
As Long
ot they can be exported, edited in notepad or similar and them imported
back.

Perhpas they are modified by time updates but doubt it. Messing with
people's registry settings is unlikely to win friends and influence
people. Well, of course if you are MS, obviously you don't care about
that.

But what are they? They're supposed????to be SystemTime Types
Private Type SYSTEMTIME
wYear As Integer
wMonth As Integer
wDayOfWeek As Integer
wDay As Integer
wHour As Integer
wMinute As Integer
wSecond As Integer
wMilliseconds As Integer
End Type

but they don't look like that to me. Perhaps Windows cheats on the
storage and just stores the ordinal of the Sunday with respect to month
in place of day of week and hour in place of day (day of month).

Key Name:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\TimeZoneInformation
Class Name: <NO CLASS>
Last Write Time: 2006-04-02 - 05:38
Value 0
Name: Bias
Type: REG_DWORD
Data: 0x12c

Value 1
Name: StandardName
Type: REG_SZ
Data: Eastern Standard Time

Value 2
Name: StandardBias
Type: REG_DWORD
Data: 0x0

Value 3
Name: StandardStart
Type: REG_BINARY
Data:
00000000 00 00 0a 00 05 00 02 00 - 00 00 00 00 00 00 00 00
................


Value 4
Name: DaylightName
Type: REG_SZ
Data: Eastern Daylight Time

Value 5
Name: DaylightBias
Type: REG_DWORD
Data: 0xffffffc4

Value 6
Name: DaylightStart
Type: REG_BINARY
Data:
00000000 00 00 04 00 01 00 02 00 - 00 00 00 00 00 00 00 00
................


Value 7
Name: ActiveTimeBias
Type: REG_DWORD
Data: 0xf0

ramble ... ramble ... ramble
 
S

smartin108

James said:
You and David have a great idea. You only need to worry about your data
for a maximum of four weeks per year :), the week between the false
changing of the clock until the synchronization, the week between the
failure to change the clock and the synchronization, and the two weeks
for the vice-versa case.

James A. Fortune
(e-mail address removed)

Well I was /trying/ to be funny anyway (^: You're absolutely right.
Actually, I'm a little surprised this pronouncement didn't create more
noise. Looking at Google Trends, the news went out, but it seems very
few people listened.

http://www.google.com/trends?q=daylight+saving+time
 
C

CDMAPoster

Lyle said:
But what are they? They're supposed????to be SystemTime Types
Private Type SYSTEMTIME
wYear As Integer
wMonth As Integer
wDayOfWeek As Integer
wDay As Integer
wHour As Integer
wMinute As Integer
wSecond As Integer
wMilliseconds As Integer
End Type

but they don't look like that to me. Perhaps Windows cheats on the
storage and just stores the ordinal of the Sunday with respect to month
in place of day of week and hour in place of day (day of month).

Key Name:
...
Value 3
Name: StandardStart
Type: REG_BINARY
Data:
00000000 00 00 0a 00 05 00 02 00 - 00 00 00 00 00 00 00 00
................
Value 6
Name: DaylightStart
Type: REG_BINARY
Data:
00000000 00 00 04 00 01 00 02 00 - 00 00 00 00 00 00 00 00
................

I'm very impressed that you dug out this information. Also, the
information that Gord provided was something I didn't consider.

I think your theory is pretty close. One problem is that there isn't
always a 5th Sunday in October. Would the OS figure out that the day
of the date is greater than 31 and "fall back" ;) to the 4th Sunday?

James A. Fortune
(e-mail address removed)
 
D

David W. Fenton

Per David W. Fenton:

Any idea what that service is called?

I popped MyComputer|Manage|Services And Applications|Services and
didn't see anything called "Time".

Windows XP Pro.

Windows Time.

But just after I posted, I realized what someone else has already
said, that it doesn't have an effect on the local time setting, so
won't fix this problem.

I'd assume there will be a patch through Windows Update for this.
Dunno what happens to older versions of Windows that aren't
supported any longer.
 
D

David W. Fenton

However, since my little ol' PC synchronizes with time on the net
every week or so, should I worry?

That sets GMT, which won't address this particular problem.

And why only once a week? The Windows Time service checks a couple
of times a day.
 

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments. After that, you can post your question and our members will help you out.

Ask a Question

Top