File allocation requirements

If MYPROG is a program that is normally executed in z/OS Batch, you must use the TSO ALLOC command to allocate needed data sets before invoking MYPROG under IDF. When you exit IDF, use the TSO FREE command to release these data sets.

Also remember to allocate and free the DDs that are needed for IDF operation. These include:

ASM: Used to access the PDSs holding the IDF REXX EXECs used to customize IDF for a particular task.
ASMLANGX: Used to access the PDSs holding the IDF Language extract data files, if you want source-level debug.

If you plan to execute the program more than once under IDF, write these commands into a REXX EXEC or CLIST.