gtps2m3zACF/SNA Data Communications Reference

About the PIU Trace Table

The PIU trace table resides in core storage in the TPF system. The size of the PIU trace table is defined in keypoint 2 (CTK2) using the TRACSZ parameter in the SNAKEY macro. See TPF ACF/SNA Network Generation for more information about the SNAKEY macro.

The number of entries in the PIU trace table varies depending on the size of the PIU trace table and how many bytes of the request/response unit (RU) are being stored in the PIU trace table.

The PIU trace table operates in wraparound mode; that is, once all of the entries in the PIU trace table are used, the TPF system begins overwriting the oldest entries with the new data.

To store data in the PIU trace table, you must first start the PIU trace facility and specify which data you want to trace. When you no longer want to trace data, you can stop the PIU trace facility. At any time, you can display the status of the PIU trace facility and the type of data you are tracing.