Hooray! Apple has now posted Drive Setup 1.3.1 and Read Me file. This is the version that (hopefully) fixes the blinking question mark startup problem that has plagued especially Macs with IDE drives. Or as Apple put it: "This software prevents the issue where the System partition is trashed at shutdown, and you receive a flashing question mark when you power up." (See next item and special report for more details). (Thanks, David Freeland and Doug Grinbergs.)
Note: The Read Me files states: "This update is only required by Apple computers that have an internal ATA (IDE) hard disk." It then goes on to list the models that fit this description. Interestingly, it does not list PowerBook models (such as my 3400) that have an internal IDE drive. Indeed, these PowerBooks have not been mentioned as having the problems that necessitated this update. I am not sure how or why these PowerBooks are immune, but they apparently are.