Open source. Clunky interface, but incredibly powerful for generating static database files that can be read on any OS via Java.
Mark your calendar for every 6 months. Reconnect the disk, and run a "Verify Checksums" command. This tells you if your physical storage is rotting. advanced disk catalog
This feature allows the user to create a that aggregates file paths from multiple cataloged sources into a single, unified directory tree, regardless of which physical disk the files currently reside on. Open source