Retrospect, Mac OS 8.1 and the end of Daylight Saving Time

Previously, we described a Daylight Saving Time bug in Mac OS 8.1. Pat Lee (of Dantz Development) summarizes the symptom and reminds users that it poses a significant problem for Retrospect:

With the change off of Daylight Saving Time this weekend, there is the potential for users to back up too much data. The reason for this is that the Mac OS 8.1 implementation of HFS changes the date/time stamps for all files when the Daylight Saving Time setting is changed. Mac OS 8.1 changes the date/time stamp for all files by one hour, causing Retrospect to think that all files on the hard drive have changed.

One solution is to update to Mac OS 8.5 - today - before changing the Daylight Setting Time option. Mac OS 8.5 correctly deals with changes to the Daylight Saving Time option and does not change the date/time stamp for files. If you do not wish to do this, Pat adds:

We recommend that this take this opportunity do a full backup to a new backup set this weekend. The caveat is that the user needs to change the Daylight Saving Time setting BEFORE doing the full backup.

For more details, see Dantz Technical Note 405.