Specifying a nonzero value for BUFNO in a DD statement for a direct access bound library causes the z/OS OPEN service to automatically allocate a buffer pool in below-the-line storage.

To prevent this from happening, you should not code BUFNO values in the DD statement for SAS direct access bound libraries.

In a future software release, BUFNO values that are specified in the DD statement should be ignored. When attempting to tune SAS I/O processing, you should instead use the BUFNO= SAS system option.

This problem does not occur for sequential access (which is also called tape format) bound libraries.

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