[ntp:questions] Window XP - ntp / GMT not working

Rob nomail at example.com
Thu May 7 11:12:02 UTC 2009

David J Taylor <david-taylor at blueyonder.not-this-part.nor-this.co.uk.invalid> wrote:
> David Lord wrote:
> []
>> On Windows 98 here (GMT) London seems to be BST with an hour
>> adjustment for DST so turning off DST is always an hour off UTC.
>> I have timezone set as (GMT) Casablanca, Monrovia. :-)
>> David
> That's interesting.  On the Windows-32 systems, London = "GMT" = UTC, and 
> having the "Automatically adjust clock for daylight saving changes" 
> checked makes the reported time UTC+1 in the summer, and UTC in the 
> winter.

Because Windows actually adjusts the CMOS clock when DST begins or ends
(as opposed to keeping the clock in UTC and applying a different offset),
it keeps state information about having done that already.

Therefore, "Automatically adjust clock" is not merely referring to
the automatic change of offset, but to the actual action of changing
the clock setting.  So if you remove that checkmark while DST applies,
it will probably not change your time setting at that instant.  The
clock remains 1 hour ahead because it already was.

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