This information is intended to help you to use system macros to access and modify the volume table of contents (VTOC) and VTOC index. The direct access device storage management (DADSM) routines control space allocation on direct access volumes through the VTOC for a volume and through the VTOC index if one exists. A storage administrator uses the ICKDSF utility to build these structures. See Creating the VTOC and VTOC Index.