Indiana will be observing daylight savings time

On Sunday April 2nd, 2006 at 2am, most of Indiana will start to observe daylight savings time for the first time since 1970. At 2am the time will be suddenly shifted to 3am. For those that have never lived in a DST time zone, you can use this simple mnemonic device to remember which way the hours go during the year:

spring forward, fall back

Fall back will happen at 2am on Sunday, October 29th 2006; this is when we will experience the hour between 01:00 and 02:00 twice.

In 2007, DST itself is changing to be 4 weeks longer so that it will start on March 11th and end November 4th. This alerted the rest of the country to some of the problems that Indiana faced with changing timezone data on computers in 2006.

The Technology Factor

It is unknown what we can expect in the way of problems from this change. There are still a lot of people who don't know that the change is taking place and the change has been implemented so fast that it hasn't allowed a lot of time for computers to be upgraded with the new timezones. Older systems may no longer be patch-able. If you can, change your timezone to EST and turn on daylight savings time calculation.

Unix

If you use any flavor of Unix (i.e. Linux, Mac OSX, *BSD, Solaris, etc), you should check your distribution's website or errata list for updates to the timezone files. You shouldn't just change your timezone. You should apply the updates from your distribution vendor and allow the changes that they have made to take effect. This will ensure that your timestamps will be correct.

Depending on your fladov/distro; you'll update or patch one of two files/packages:

• some systems keep timezone data in the glibc library (HP-UX, RHEL 2.1 for example)
• -or-
• some systems keep a seperate tzdata package (RHEL 3, RHEL 4 for example)

Just make sure that your glibc or tzdata packages/libraries are updated and you'll probably be good to go. The update of glibc and tzdata will patch the entry for Indiana, so that machines using Indiana (or Indiana-east, or east-Indianapolis, or Indianapolis, etc) as their localtime setting will start to observe DST.

Reading your log files can be particularly interesting; in the Spring you have a 1 hour gap in timestamps, and in the Fall, you have a 1 hour overlap of timestamps. If your system time is in the UTC or GMT timezones then this will not be a concern since UTC/GMT does not observe daylight savings time.