Daylight Saving Time 2007—Operating Systems: Macintosh

Macintosh Overview

Macintosh computers comprise a large percentage of computers used across campus by faculty, staff, and students. ITS manages about 650 Macs in academic computer labs and nearly 120 SCARPIES installations as well as providing support for individuals and departments who use Macs in the course of their academic, research, and administrative responsibilities.

Impact of Daylight Saving Time Change on this Technology

The new beginning and ending dates for daylight saving time affect Macintosh computers in two ways. First, since the hardware clock settings are maintained by the system software, users need to take steps to insure that system time matches local time. Second, core technologies that maintain their own rules for dealing with date and time (such as the Java runtime environment (JRE)) must be modified to deal with these changes.

Remediation Steps for Customers

Even if you have your clock synchronize to a network time server (the Set date & time automatically checkbox in the Date & Time system preference) you will need to be responsible for your computer’s clock as the timeserver marks time in Universal Coordinated Time (UCT) and makes no changes for daylight saving time. Macintosh users need to address both the system and Java time issues, and ITS recommends the following steps be taken:

For users of Macintosh OS X 10.4.x (Tiger):
Install Apple's Daylight Saving Time update. The recommended method is by running the Software Update system preference. (If you are not familiar with Software Update please visit
http://docs.info.apple.com/article.html?artnum=106704 for more information.) If you choose, you may download and install this update manually from www.apple.com/support/downloads/daylightsavingtimeupdatetiger.html

Install Apple’s Java for Mac OS X 10.4 Release 5 update. The recommended method is by running the Software Update system preference. (If you are not familiar with Software Update please visit
http://docs.info.apple.com/article.html?artnum=106704 for more information.) If you choose, you may download and install this update manually from www.apple.com/support/downloads/javaformacosx104release5.html

For users of Macintosh OS X 10.3.x (Panther):
(Note: Although ITS does not support versions of Mac OS prior to 10.3.9, these updates should be applied to any version of 10.3 a user may be running.)

Install Apple's Daylight Saving Time update. The recommended method is by running the Software Update system preference. (If you are not familiar with Software Update please visit
http://docs.info.apple.com/article.html?artnum=106704 for more information.) If you choose, you may download and install this update manually from http://www.apple.com/support/downloads/daylightsavingtimeupdatepanther.html

Install Apple’s Java for Mac OS X 10.3 Release 5 update. The recommended method is by running the Software Update system preference. (If you are not familiar with Software Update please visit
http://docs.info.apple.com/article.html?artnum=106704 for more information.) If you choose, you may download and install this update manually from http://www.apple.com/support/downloads/javaformacosx103update5.html

For users of Macintosh OS X 10.0.x, 10.1.x, or 10.2.x:
Neither Apple nor ITS support these versions of the Mac OS. No updates are available for either the system or Java daylight saving time issues. If you cannot upgrade to 10.3.9 or 10.4.x you will need to adjust your clock settings manually. In the Date & Time system preference, uncheck the Set date & time automatically checkbox. You will then need to manually set the clock on March 11 and again on April 1 to match local time. This will also need to be done on October 27 and on November 3. There is no solution available for updating the versions of Java the exist on these systems and users should be aware that they may encounter serious issues with any Java or Javascript applications, applets, or web sites that you may use.

For users of Macintosh OS 9.2.2 and earlier:
Neither Apple nor ITS support these versions of the Mac OS. No updates are available for either the system or Java daylight saving time issues. If you cannot upgrade to 10.3.9 or 10.4.x you will need to adjust your clock settings manually. In the Date and Time control panel deselect the option to observe Daylight Saving Time changes automatically. You will then need to enable daylight saving time manually on March 11 and disable it manually on November 3. If you are running applications in the Classic environment of OS X, those applications will honor the daylight saving time time settings in your version of OS X.

Additional Information

More information about the daylight saving time changes and its impact on Macintosh computers is available at http://docs.info.apple.com/article.html?artnum=305056

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