sysdate, Time Zones and GMT

In article <3t5h87$40p_at_light.twinsun.com> eggert_at_twinsun.com writes:

 [...deleted...]
>
> I don't know of any database vendor who supports timezones well,
> though some operating systems do:
> SunOS 4, SVR4-derived OSes like Solaris and Unixware,
> Nextstep, Linux, BSDI, and probably some others.

From memory HPUX 7, 8, ... had a file which contained an entry for most countries, (and in the case of Australia, each state,) with an algorithm for working out when daylight saving started and finished.

Algorithm was something like:

     if  today is sunday
     and 1 <= date <= 7
     and month = october
     and 02:00 <= time <= 03:00
     and year is ... then
         must be start of daylight saving.

This is based on my (poor) memory of several years ago, but at the time it all appeared to be very clever and for the two years I was at the site, the time changes worked correctly each year.

---
John Wright             CSC Australia, Canberra.
johnw_at_canb.auug.org.au  100032.553_at_compuserve.com
Voice +61 6 201-8470    Fax +61 6 201-8499