Intech's Disk Defrag Utility for MacOS 9.1 or later
Now included free as part of Hard Disk SpeedTools!
Intech's Disk Defrag utility is designed to speed up your Macintosh's access to files stored
on your hard disks. To do this, the Disk Defrag utility identifies files on HFS+ formatted
drives which are stored in more than one place on your drive and rewrites those files so that
they form one continuous data stream. This process can dramatically reduce the number of data
reads and writes to access your files, thereby significantly speeding up file access related functions.
Better yet, Disk Defrag Classic can even defragment files on your boot volume and your MacOS X volumes!