WinDirStat - WinDirStat is a disk usage statistics viewer and cleanup tool, inspired by KDirStat.
Caffeine for Windows - Prevent your computer from going to sleep
WizTree - WizTree quickly finds the files and folders using the most space on your hard drive. It scans the MFT (Master File Table) instead of crawling the entire disk which makes it very fast.
Caffeine for Linux - Inspired by the Mac OS X version, Caffeine for Linux is a status bar application able to...
SpaceSniffer - SpaceSniffer is a freeWare (donations are welcome) and portable tool application that lets you understand how folders and files are structured on your disks.
Caffeine for Mac - Caffeine is a tiny program that puts an icon in the right side of your menu bar.