topic Re: VMS732_TZ-V0100 - GMT- and GMTPLUS swapped in Operating System - OpenVMS

VMS732_TZ-V0100 - GMT- and GMTPLUS swapped

Sebastian Bazley — Wed, 03 May 2006 11:56:19 GMT

I thought the date must be April 1st when I read the release notes, but it seems not.

The definition of the timezone names has been changed in the time-zone public database (ftp://elsie.nci.nih.gov/pub/). The
effect of this change is that, after installation of the
VMS732_TZ-V0100 kit, "GMT-" (minus) will now mean "ahead (east) of"
Greenwich Mean Time (GMT) and "GMTPLUS" will now mean "behind
(west) of" GMT. For example, GMT-1 will mean one hour ahead (east)
of GMT and the Time Differential Factor (SYS$TIMEZONE_DIFFERENTIAL)
will be set to "3600". GMTPLUS1 will mean one hour behind (west)
of GMT and the SYS$TIMEZONE_DIFFERENTIAL will be set to "-3600".
This is the opposite meaning of what you are used to.

We're rather wary of installing this - anyone got any advice?

Re: VMS732_TZ-V0100 - GMT- and GMTPLUS swapped

John Gillings — Wed, 03 May 2006 17:53:04 GMT

Sebastian,

This was a change imposed by the standards people. I don't think it will affect you unless you want to use the generic GMT* time zone names. There was a problem with those names - they contained a "-" character which didn't work in all cases. Given the long time it took to discover the bugs kind of confirms my belief that they were defined for syntactic completeness, and not actually seriously used by anyone.

From your profile, I'd guess you're in the GMT zone, so may not have a use for the plus or minus zone names anyway... ;-)

Haven't heard of any problems from folk installing the TZ kit. NOT installing it will cause problems if you want to calculate times in any of the updated time zones (mostly in North America and Asia)

Re: VMS732_TZ-V0100 - GMT- and GMTPLUS swapped

Ian Miller. — Thu, 04 May 2006 03:08:15 GMT

Note to get the full fixes you need the CRTL update kit as well.

Re: VMS732_TZ-V0100 - GMT- and GMTPLUS swapped

Sebastian Bazley — Thu, 04 May 2006 05:29:23 GMT

[Thanks, I know about the CRTL patch]

Thanks also for explaining why the "-" was removed. Not sure I understand why PLUS has changed, though.

Yes, I am in GMT/BST time zone.

But I believe that some of our customers are in places around the world for which there is no suitable named timezone, so they are set up with GMT offset zones. Not ideal, especially if they have DST.

[We need to double-check all the customers using GMT offset zones, and change them to a suitable local name if at all possible.]