This post is very old and likely contains information that is no longer accurate and links which no longer work. Proceed with caution.
So as a resident of Indiana, today is my first day of Daylight Saving Time and I am not happy at all. In addition to having to reset all of the clocks, I also had to change the time zones on all of the computers – Easy enough on Windows, you can just change the time zone to Eastern. However, all my FreeBSD servers required a download and recompile of new time zone definitions. Not just that, but most programs that were started before the time zone switch will not pick up the change until they are restarted. In some cases, it’s safer to just reboot the whole server to make sure everything is running on the same clock. And I hate having to reboot servers.
The reasoning behind the FreeBSD time zone updates is explained in an article on Observing Daylight Saving Time (DST) - ECN @ Purdue. The gist of it is that past file dates can be miscomputed if the time zone is simply switched to Eastern.
Many users of calendaring programs will be bitten by similar problems, causing appointments set before the change to exhibit all kinds of odd behavior.
Personally, I have not seen enough compelling evidence to show that the clock changing business actually saves any energy. It does, however, mess with people’s internal clocks and cause many traffic accidents. Most of the figures done showing that it saves energy seem to be from the 1970’s. I doubt the governer thought about the thousands of man-hours lost in actually changing the clocks, on computers and servers especially - but he sure was sympathetic about the possible loss of an hours worth of drinking at bars!
The only positive effect is that the Indiana legislature will now debate over things that actually matter, instead of over DST.
I’m sure that come Monday I will have to deal with quite a few calls from people who, rather than changing the time zone on their PC, have simply run the clock ahead an hour - only to find out that the clock resets when the Internet Time function resyncs.