HDGraph, is a free tool for Windows able to draw multi-level pie charts of disk space usage. It shows all the directories and sub-directories of the hard drive on a single graph, allowing to see the largest directories at a glance.
HDGraph is compatible with all storage visible in the Windows explorer : folder of hard disk drive, usb pen drive, network folder, cd, dvd etc.
Requirements: Windows 7, Windows Vista, Windows XP with Microsoft .NET Framework v. 2.0 or above
License: HDGraph is free under CeCILL license