MODBLKS data set enhancement

Previously, a MODBLKS data set could be defined only as a partitioned data set (PDS), which limited the size of a MODBLKS data set member to 16 M. However, because a PDSE member can be up to 2 G in size, you can define a MODBLKS data set as a PDSE to store a greater quantity of the IMS system definition output for the control block modules that are affected by online change.

This enhancement is delivered with APAR PI90417 (PTFs UI57447 and UI57448).

Coexistence considerations

The active MODBLKS data set can be a PDS, and the inactive MODBLKS data set can be a PDSE, and vice versa.

Both the active and inactive MODBLKS data sets that IMS cold started with can be PDSs or PDSEs.

Online change supports switching between a MODBLKS PDS and a MODBLKS PDSE and vice versa.

Changes to troubleshooting for IMS

For a complete list of all of the new, changed, and deleted messages, and abend codes in IMS 15, see Message and code changes in IMS 15.

Documentation changes

The following table lists the publications that contain new or changed topics for the MODBLKS data set enhancement. Publications that are not impacted by this enhancement are not included in the table.