[tz] Wrong timezone Information provided

Brian Inglis Brian.Inglis at SystematicSw.ab.ca
Fri Oct 7 18:03:04 UTC 2022


On 2022-10-06 14:25, Brooks Harris via tz wrote:
> On 2022-10-06 4:07 PM, Paul Eggert wrote:

>> Yes, as I understand it Microsoft Windows 8.1 and later has data 
>> derived from tzdb in its Windows Runtime / Universal Windows Platform 
>> classes. 

Uses MS port of tz code/data for UWP Store apps.

> The time zone information resides in the Windows Registry, at
> HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones

Used by native MS Windows libraries and apps: MS do their own thing 
here. It would not be too hard to convert from tz to MS reg data to 
provide correct times in earlier years.

Windows dynamic time zones may have been added to support the EU 2006 
and/or US 2007 changes, and new data is now added for other zones.
The earliest dynamic zone I can find is for Cuba 2003.

Base data is static current e.g. Cuba Standard Time

Display (REG_SZ) = "(UTC-05:00) Havana"
Std (REG_SZ) = "Cuba Standard Time"
Dlt (REG_SZ) = "Cuba Summer Time"
MUI_Display (REG_SZ) = "@tzres.dll,-2430"
MUI_Dlt (REG_SZ) = "@tzres.dll,-2431"
MUI_Std (REG_SZ) = "@tzres.dll,-2432"
TZI (REG_BINARY) = 2c 01 00 00 00 00 00 00

but some zones also support 'Dynamic DST' e.g.

FirstEntry (REG_DWORD) = 0x000007d3 (2003)
LastEntry (REG_DWORD) = 0x000007dd (2013)
2003 (REG_BINARY) = 2c 01 00 00 00 00 00 00
2004 (REG_BINARY) = 2c 01 00 00 00 00 00 00
2005 (REG_BINARY) = f0 00 00 00 00 00 00 00
2006 (REG_BINARY) = 2c 01 00 00 00 00 00 00
2007 (REG_BINARY) = 2c 01 00 00 00 00 00 00
2008 (REG_BINARY) = 2c 01 00 00 00 00 00 00
2009 (REG_BINARY) = 2c 01 00 00 00 00 00 00
2010 (REG_BINARY) = 2c 01 00 00 00 00 00 00
2011 (REG_BINARY) = 2c 01 00 00 00 00 00 00
2012 (REG_BINARY) = 2c 01 00 00 00 00 00 00
2013 (REG_BINARY) = 2c 01 00 00 00 00 00 00

-- 
Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

This email may be disturbing to some readers as it contains
too much technical detail. Reader discretion is advised.
[Data in binary units and prefixes, physical quantities in SI.]


More information about the tz mailing list