Originally posted by ericpeden
Disk fragmentation has little to do with the format in which directory information has stored. Fragmentation is caused when one file is split up into non-contiguous pieces spread out across the physical disk. It takes time for the drive to spin around and pick up those pieces when it comes time to read or modify the file, especially if there a lot of little pieces spready very far apart from one another. Macs suffer from fragmentation just as much as any other computer, although as pointed out above Panther includes some automatic defragmentation features that are meant to reduce the problem.
Incidentally, both TechTool Pro 4 and the latest Norton Utilities have disk optimizers that are supposed to work in OS X. However, TTP4's caused some massive disk damage to one of my partitions when it just stopped working while I was booted off the TTP4 CD. I suspect it ran out of memory and just locked up, but restarting the machine (my only option) left the disk in an unpleasant condition I am still trying to get it out of--portions of files were overlapped, so that, for example, while playing an MP3 I will suddenly hear snippets of an MPEG music video stored on the same drive. Frustrating and impossible to detect without trying to use every single file on the partition. Norton's optimizer refused to acknowledge that I had any hard drives at all. Go figure.
