[tz] tz abbreviations / zdump for programmers

Ian Abbott abbotti at mev.co.uk
Wed Jun 6 15:08:35 UTC 2012

On 2012-06-06 12:46, Ian Abbott wrote:
> On 2012-06-06 11:52, Clive D.W. Feather wrote:
>> John Haxby said:
>>> It's not that long ago that someone thought we in the UK were on GMT
>>> all year round.
>> Microsoft still do (or at least seem to think that "GMT" means "UK legal
>> time").
> In the registry, there is a
> sub-key called 'GMT Standard Time' that contains a registry value 'Dlt'
> set to "GMT Daylight Time". I don't know if that string registry value
> ever gets displayed by the system in normal operation.

It's been pointed out to me that XP systems set to this zone will show 
"GMT Daylight Time" and in fact I have XP systems showing that.  The XP 
system that showed "GMT Standard Time" was only recently installed and 
hasn't seen any DST transitions yet, although that is no excuse for 
showing the wrong DST information.  It might have been something to do 
installing it in a virtual machine running under Linux, so if that's the 
reason for it showing the wrong DST information, I apologize to 
Microsoft.  (I don't have the time or inclination to install XP on real 
hardware at the moment to check.)

I also noticed that Windows 7 displays the same zone name to the user as 
"(UTC) Dublin, Edinburgh, Lisbon, London" with a note underneath to say 
that Daylight Savings is in effect.  Perhaps the use of "UTC" to mean 
"legal time in Eire, Scotland, Portugal and England" is even more 
confusing than "GMT"!

-=( Ian Abbott @ MEV Ltd.    E-mail: <abbotti at mev.co.uk>        )=-
-=( Tel: +44 (0)161 477 1898   FAX: +44 (0)161 718 3587         )=-

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