Included are a Windows version, a commandline version (for scheduling by the task scheduler or for use from administrator scripts), a screensaver version, a DLL library (for use from programming languages), versions for Windows X64, and the complete sources.

Why use this defragger instead of the standard Windows defragger?
Much faster.
Totally automatic, extremely easy to use.
Optimized for daily use.
Disk optimization, several strategies.
Directories are moved to the beginning of the disk.
Reclaims MFT reserved space after disk-full.
Maintains free spaces for temporary files.
Can defragment very full harddisks.
Can defragment very large files.
Can defragment individual directories and files.
Can be run automatically with the Windows Scheduler.
Can be used from the commandline.
Can be used as a screen saver.
Can be run from cdrom or memory stick.
Sources available, can be customized.
JKDefrag was open source, but from version 4, when it changed its name to MyDefrag, it is closed source.