The DYNAMNBR parameter is used to indicate how many Task I/O Table (TIOT) slots to reserve for datasets that may be dynamically allocated during the job step. This parameter is equivalent to coding DD statements with the DYNAM keyowrd.
Syntax: DYNAMNBR = n
where "n" is a number in the range 0where D= no of DD stmts in the job step.
DYNAMNBR reserves space in the TIOT for the use of dynamically allocated datasets.