Windows only: Disk utility FosiX Lite is a visual hard disk analyser in the vein of previously covered WinStatDir and JDiskReport. What sets FosiX apart is the interactivity of the bar charts and pie graphs it produces. Run the application and see that you have two directories at the root level taking up a huge amount of space? Click on one and you're immediately inside the directory looking at new graph showing how space is distributed in that directory. FosiX lets you quickly see and drill down through large directories to get a sense of how your data is stored and the amount of space it is taking up. FosiX Lite is a free download for Windows only.