Time Zone Editor

Jesper Nørgaard jnorgard at Prodigy.Net.mx
Sat Jul 1 06:02:08 UTC 2000

The short version: Cut the below text to a text file and save it as tzsydney.reg.


[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Time Zones\Sydney]
"Display"="(GMT+10:00) Melbourne, Sydney"
"Dlt"="Sydney Daylight Time"
"Std"="Sydney Standard Time"

Now double click on tzsydney.reg which will load this to the registry. You should now be able to open Date/Time from Windows Settings and select "(GMT+10:00) Melbourne, Sydney" and click on the optionsbutton below so that Windows is handling daylight saving automatically. That is all there is to it! :-)

First of all let me say I haven't tried it in Windows NT, only in Windows 95. According to documentation probably the key above would be
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones\Sydney]
instead. Try it for yourself. I did use tzedit.exe to view the time zones in a Windows NT computer, and that worked fine. I did not try to update with it on the Windows NT computer.

As mentioned in earlier mails Mickeysoft has made a program called Windows Time Zone Editor which handles these matters without having to fumble around with the registry editor poking in hexadecimal values. I have created a registry file with all known timezones that we know on the mailing list.

If you are interested in this, please download the file http://timezone50.homepage.com/tzedit.zip which contains the following:

tzedit.exe	The Time Zone Editor
tzedit.hlp	Help file for the program
tzedit.txt	A text file I prepared with the information about which time
		zone in tznew.reg corresponds to which country.
tznew.reg	Registry file with all the timezones documented in tzedit.txt
		and the correct start and end times for year 2000. You can
		either import the full file into the registry, or copy-and-paste
		the time zone(s) you want first to another *.REG file, and
		then double click on that.

These files can be used for any purpose you have, its "use-at-will-ware" :-)

I have investigated this to include in my PC program Time Zone Converter (see also http://timezone50.homepage.com) but that hasn't been included yet. You might want to try the PC program though.

Just to continue the discussion, I have noticed a problem at least in Windows 95. I don't know if it is also a problem in Windows 98 or Windows NT. I would be grateful if anybody knows or can investigate this on these machines.

The problem:
When using a time zone that has automatic daylight savings handled by Windows 95, then everything works fine if you turn off your computer every night before going to bed as any good Mickeysoftian :-)
However, if you keep it on 24 hours a day, then there is a problem when leaving daylight saving. Lets say that at 3 o'clock in the morning Windows turn back the clock to 2 o'clock as it should. Then it was supposed to let time run ahead until 3 o'clock again, but now not turn the clock 1 hour back (since it reached 3 o'clock for the second time) but continue. Unfortunately it goes into an "endless" loop repeating to turn it back to 2 o'clock. The only way to leave this diabolic situation is to turn time ahead to after 3 o'clock, but at this point the registry has been screwed up.

Any information about this will be of interest.

Jesper Nørgaard
Email: jnorgard at df1.telmex.net.mx	
CIMMYT  -  Centro Internacional de Mejoramiento de Maíz y Trigo
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