Power On Software's Rewind -- a utility that promises to undo changes you've made to your Mac by sending the state of your Mac's hard drive "back in time" -- should serve as an object lesson on how not to release a piece of software. Rewind generated a deafening buzz at July 2000's Macworld Expo, and normally skeptical reviewers positively gushed about the utility after seeing a demo. And then Power On released Rewind 1.0, a program so buggy that a subsequent update appeared to be designed only to disable Rewind's most unstable components. The latest version, 1.1, delivers much of what the program promises, but some problems remain.
Back in Time
The theory behind Rewind is easy to grasp. It tracks changes you make to your hard drive -- software installations, changes to the System Folder, and the trashing of items, among other things -- and stores data related to these actions in a hidden database. If you do something you're unhappy with you -- download a virus, for example -- you can command Rewind to return your Mac to the state it was in before you initiated that action.
If you've done something so destructive that you can't boot from your hard drive, Rewind lets you start your Mac from Emergency Disk -- a hidden, user-configurable partition that contains a System Folder and diagnostic utilities -- by holding down the R key at start-up. Rewind can also recover files you've trashed.
In tests where we rewound individual files and recovered trashed files, Rewind performed admirably. And it fared reasonably well when recovering entire disks, but Rewind's performance wasn't perfect. For example, after installing two troubleshooting utilities on a PowerBook G3, we rewound the disk to the previous day. Rewind failed to remove the folders for the recently installed utilities, as well as one or two files inside the folders. However, reversing the process -- sending the drive forward to a time after we installed the utilities -- brought the files back as originally installed.
After a drive is rewound, Rewind's database temporarily eats up a lot of disk space; your Mac must be inactive for ten minutes before Rewind will purge older files in its database and restore that disk space. It would be helpful if Rewind included a Purge Now command.
Bring It Back: Rewind 1.1 allows you to return your Mac to a previous state -- that is, when the program functions properly.