Okay, So - it wasn't a JVM issue. Updating it did not change the results.
And Steve was right, in a way. But I still don't understand why it should be this way. First, Steve, I understand what you're saying about "whenever you display a time." But in practice, I'm not displaying a time at all. I'm simply creating a date/time value and adding a number of seconds to it, then inserting into a database. So to my way of thinking - and according to every doc I've ever read - the dateAdd function should do exactly what you tell it to do: just add the increments to the original date. But what's happening DOES involve DST - though not the time zone. I don't know why. It shouldn't. But it does, at least in CF9. Try this for yourself: Daylight Savings Time began at 2:00 AM Eastern on March 14, 2010. So run the following: <cfset myDate = createDate(2010,3,14) /> <cfdump var="#myDate#" /><br><br> <cfset myDate2 = DateAdd('s',1271779666,myDate)> <cfdump var="#myDate2#" /><br><br> myDate is two hours _before_ DST went into effect. On two different CF9 servers, one on EDT, the other on CDT, the result for myDate2 was: {ts '2050-07-01 17:07:46'} Now change the createDate to (2010,3,15) - _after_ DST went into effect. On the same servers, the result was: {ts '2050-07-02 16:07:46'} The original date was changed by a day. But the result of the dateAdd statement changed by 23 hours. I wish I could test this on CF8 and/or 7, but the only servers with those versions to which I have access are in Arizona, where they don't use DST. Those servers return the 16:07:46 timestamp. But without having the machines set to DST, I can't tell if CF is acting differently or not. If someone has access to those versions on a DST machine, please try this and see what you get. I'd really be curious to know if this is a CF9 thing. Maybe I've just misunderstood how dateAdd works - although the docs simply say "Adds units of time to a date." There's no mention of DST affecting it. But it's certainly doing so. So in brief: when you dateAdd, the result will be affected by DST - at least, based on whether your added timespan crosses the DST threshhold for the current year. I have no idea if it tries to figure out whether the resulting date/time is during DST or not. In most instances, this might not even be noticed. But in my case, where I'm receiving a timestamp from an external device as a Unix epoch time, then converting it to a date/time object by adding the epoch time to the date of 1/1/1970, the result is not what I want, since all I'm trying to do is recreate the time from the original device. The DST addition causes the timestamp to be wrong by an hour. Frustrating, but at least I now understand what's happening. Hope this will help someone else avoid the same frustration. -- Thanks, Tom Tom McNeer MediumCool http://www.mediumcool.com 1735 Johnson Road NE Atlanta, GA 30306 404.589.0560 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| Want to reach the ColdFusion community with something they want? Let them know on the House of Fusion mailing lists Archive: http://www.houseoffusion.com/groups/cf-talk/message.cfm/messageid:333085 Subscription: http://www.houseoffusion.com/groups/cf-talk/subscribe.cfm Unsubscribe: http://www.houseoffusion.com/groups/cf-talk/unsubscribe.cfm