If you reject a scratch or rename request in IGGPRE00, scratch and rename provide a status code that indicates an I/O error.
In the integrated catalog facility environment, VSAM deletes the VVR entry first and then calls DADSM to continue with the scratch of the format-1 DSCB when deleting a data set. If IGGPRE00 rejects the scratch request, the VVR entry has been deleted, but the format-1 DSCB still exists. This makes the data set inaccessible and corrupts the catalog by creating inconsistencies between the BCS, VVDS, and VTOC. You are responsible for ensuring that your IGGPRE00 routine does not reject a DADSM scratch request for a VSAM data set. You can test bit DS1ORGAM in the DSCB, which is on for VSAM data sets.