Isn't Diamond Edge a brilliant program? One of its features is 'Test Disk' which scans for various types of potential problems and, only the other day, this saved my bacon because Drive C (a 32MB partition) suddenly reported itself as 22MB. Why I do not know, but Diamond Edge came to the rescue and fixed several serious errors!!
I have also found it particularly useful to optimise (defrag) the partitions in order to better stream audio for (storage) demanding games (Cannon Fodder / Xenon II) or other programs like ST Video Player. I try and defrag the drives on a monthly basis. Don't even get me started with Undelete, another superb part of the Diamond Edge suit!
Diamond Edge is one of the most fundamental utilities for all Atari computers equipped with a hard drive. Anodyne has Diamond Edge freely available to download - which includes the manual too.