IBM® recommends that you create a BLSCUSER member to define installation-supplied exits. By default, BLSCECT embeds BLSCUSER.

IBM recommends that you do not modify BLSCECT. If you do modify BLSCECT, you will need to allocate the modified BLSCECT to the IPCSPARM data set when you start an IPCS session. Also, you must carry the installation modifications to the new BLSCECT for the next release.

For example, if you have installation-defined dump exits that were previously in MVS/XA SP load module AMDPRECT, you can add them to BLSCUSER.