Years ago, I was a technician for an office that distributed important information via sneaker net. Meaning, of course, that this was before we linked everything with cables, and information was passed around via floppy disk (remember those!). Without fail, once a week or so, someone would bring in a floppy disk that they could not read, and into the old disk doctor we would go. We would defrag the disk, using a utility that looked just like iDefrag from Coriolis Systems… except, of course, that this was ten years ago. That was my first impression at launching iDefrag, a total throw back to the mid-90’s.
iDefrag does have a nice interface, with very simple to understand controls, and an interface full of pretty colors that are fun to watch. Each of the blocks in the interface is supposed to represent a block of data on the hard drive. I was at first alarmed at how badly my disk was fragmented, as indicated by the amount of red blocks that were viewable. But then, the next question that popped into my head was, “why?”
I’ve always heard that the lack of a file defragmenter on OS X was a good thing, due to the fact that the HFS+ file system handled fragmentation automatically. This idea was enforced after my research. Amit Singh, writing for Kernelthread.com writes this as the conclusion of a very detailed paper:
“Defragmentation on HFS+ volumes should not be necessary at all, or worthwhile, in most cases, because the system seems to do a very good job of avoiding/countering fragmentation.”
Apple themselves say that fragmentation is nothing to worry about on an hfs+ drive on this page where they say:
“You probably won’t need to optimize at all if you use Mac OS X.”
So why would I need iDefrag? For the most part, you probably don’t. However, if you work with a large amount of video files, and are willing to purchase the app and go through their… rigorous licensing scheme, then iDefrag just might be for you. HFS+ automatically defragments files that are under 20 MB, but it does not defragment anything over that amount. Coriolis Systems does a great job at explaining their side of the story, but I remain unconvinced.
The performance of the app is also worth noting quickly. iDefrag froze once during a defrag of an external USB drive, and refused to defragment an external firewire drive. The latter could have been caused by a lack of available space, but for the former I had no excuse. The app will not completely defragment your boot partition unless it is un-mounted first, requiring you to be running off a CD or using your Mac in target disk mode and running iDefrag from another computer. Which, after going through their licensing I was reluctant to do.
Bottom line is, if you feel that defragmenting your HFS+ formatted drive would improve performance, then iDefrag is for you. And, it does have a very nice interface, even if it does make me want to party like its 1995.