DaisyDisk is a disk space analyzer and management software for Mac OS X. It scans your hard drive and displays its content as a sunburst graph, allowing you to quickly identify which files and folders are taking up the most space. You can then drill down into the folders, preview files, and delete any unneeded files to free up disk space. It also provides real-time disk space monitoring, plus customizable alerts when disk space is running low.
Discontinued The program seems to be no longer updated. The latest version, 2.13, released in July 2012, is fully functional and can still be downloaded from the official website.
Simple, fast, small size, portable
The free version is sufficient for my needs and is very similar to DaisyDisk.
Discontinued The official website is no longer available. The latest version, 1.3, released in June 2006, can still be downloaded from Softpedia.
Discontinued The program appears to be dead, as announced in a tweet from the author: https://twitter.com/bartheph/status/742596462807265280. The website and changelog appear to be abandoned. The latest version, 0.4.3, released at the end of 2015, can still be downloaded from the official website.
Windows based when Daisy Disk is Mac