From : x>eggert@twinsun.com To : dkelly@lhr-sys.DHL.COM Subject : Re: FW: tztab entries (forwarded with permission) CC : tz@elsie.nci.nih.gov Date : 13/08/97 00:46

Hi Paul Thanks for your help on this.

Here's what I think you're asking for. If you're interested only in times now and in the future, then the Olson database contains too many names, partly because it goes back to 1970 and thus must track historical changes, and partly because it insists on at least one name per country. You want just one distinct name for each time zone future, regardless of country.

Yes, this is exactly what we need.

This script assumes that the only thing that matters about a time zone is its UTC offset; it ignores the time zone name (e.g. "EST", "EDT") and whether the time is daylight-saving time.

Just to reassure me - I assume that futures with the same UTC offsets but with different daylight savings time change dates are considered to be distinct by the script? Can you offer any guidelines on the allocation of canonical names to these futures? The tztab entry on HP-UX does seem to follow a convention of <zone name><offset><dst zone name>, e.g.: GMT0BST, WET0WETDST, PST8PDT, CST-9:30CDT but there appear to be different variations of these, e.g. for Central Europe I could use CET-2CEST or CET-2CETDST (and that's without considering MEDST, MEST, MESZ, METDST). Also "CST" is used in China/Australia/US. What would you recommend as the most common set? Thanks again for the help Dave Kelly