Loading the 'ADSFiler' module before the desktop has been started (add 'ToBoot' to !Boot.!Run in the next directory up) has the effect of giving each floppy and each ADFS/IDE hard disc on your system an individual icon.
These icons can be edited, they are found in the Sprites file in this directory. You will need to move the Sprites file and the module into a directory called 'Startup' inside your !System directory, or change the locations inside the 'ToBoot' file.
