By default, the AIOZR2AR utility program runs above the 16MB address line, and primarily uses above-the-line storage. The z/OS default, which provides 32MB of above-the-line storage for all programs, should be adequate for AIOZR2AR. If you override the default values for the Language Environment® HEAP or STACK parameters in the EXEC PARM statement, such that the AIOZR2AR program runs below the 16MB line, you must include a REGION size. The REGION value is either 6 MB or twice the size of the largest Xerox resource that you load, whichever is larger. If you specify a smaller value, out-of-storage errors might occur.