Using IS INITIAL on the PROGRAM-ID statementStart of change or INITIAL compiler optionEnd of change

The IS INITIAL clause on the PROGRAM-ID statementStart of change or the INITIAL compiler optionEnd of change specifies that when a program is called, it and any programs that it contains will be entered in their initial or first-time called state.

There is an overhead in initializing all WORKING-STORAGE variables with VALUE clauses. The performance impact depends on the number and sizes of such variables.