The ability to play PlayStation 2 games off of a hard drive came to light when PS2 programs like HD Loader and USB Extreme became available for PS2 owners. The PS2 has an internal hard drive that uses a proprietary file system, but an external hard drive can be attached that can also store the games. The external drive needs to be partitioned and must be formatted to the correct file system before the games can be read properly.
Connect the hard drive that you want to partition for the PS2 games to your computer using its USB cable.
Right-click the "Computer" icon on the desktop of your computer and click the "Manage" option on the small menu that appears.
Click the "Disk Management" option on the left of the "Computer Management" menu. Right-click the hard drive in the volume list and click "Shrink Volume" from the small menu that appears.
Enter the size that you want the PS2 partition to be in the "Enter the amount of space to shrink in MB" space on the menu that comes up. Click "Shrink" to shrink the hard drive's main partition. A space will appear on the volume list called unallocated space.
Right-click the unallocated space and click "New Simple Volume" from the list that is displayed. Click "Next" and select "Simple" on the next page that appears. Click the "Fat32" option under the file system options. Click "OK" and the hard drive will be partitioned. There will now be two partitions on the hard drive. The Fat32 partition is the PS2 partition.