with ID identifier, 1 to 99 reserved for system IFLAG severity : 0 ZTELL may return to the calling routine 1 ZTELL may not return 2 fatal error, the run must stop --- List of ID's used by the system --- 11-14 FZOUT, RZOUT via FZOTAB 15 MZCOPY 99 MZGAR1, called for automatic garbage collection