This user exit provides additional volume verification. A new WORM tape mount indicator in the Volume Security and Verification Exit (type X'18' in the DCB exit) identifies the exit. A parameter list pointer in reg1 is passed. The parameter list is mapped by the IECOEVSE macro. A new bit flag (x'40') is added to byte OEVSFLG: OEVSWORM X'40' - WORM tape mounted.