JkDefrag is a disk defragment and optimizing utility for Windows released under the GNU General Public License. It's completely automatic and very easy to use, works fast and hardly needs system resources. JkDefrag includes two optimization strategies and can handle both floppies and USB disks or sticks. It also features a command-line version for further configuration such as using the task scheduler or administrator scripts).

There is no "setup" or "install" and no configuration file. All you have to do is download the zip and unpack. JkDefrag's interface shows a high-detail map of your hard drive, refreshed 3 times per second. Bottom-left of the window is the beginning of the hard disk. The program uses a color code to distinguish between the different types of blocks: empty, in use, defragmented, unmovable and so on.