Description from the author:
"File-system display & analysis utility. Shows partition-tables and bootsectors. Shows all HPFS internal disk structures like Superblock, Fnodes, Dirblocks etc. Check allocation integrity for volume. Can find any data-sequence on the disk and identify the file it belongs to. Display allocation maps for entire disk and for the directory-band."
DFS has an REXX ADDRESS envrionment thus you can use it from REXX programs.