Deciding if system modifications can use online change

A list of the changes that can be serviced by online change is given in the following table.

The list is based on the effect on the stage 1 system definition macros, because the stage 1 input is regarded as the control point.

Table 1. System definition resource modifications allowed for online change
System definition macro	Permissible online changes
APPLCTN	Add a PSB (application) and its attributes Change attributes Delete a PSB
DATABASE	Add a database and its attributes Change attributes Delete a database
RTCODE	Add a routing code and inquiry attributes Delete a routing code
TRANSACT	Add a transaction and its attributes Change attributes Delete a transaction

The changes listed in the table require a MODBLKS generation. The corresponding security changes require that you also update the RACF® security profiles to reflect any new IMS resources needing security.

Also, the system definition preprocessor can be a useful part of your preparation. When adding or changing resource names, the preprocessor can detect any invalid names or duplicate names and help ensure a successful system definition run. Some limitations to the modifications are explained in Planning considerations for online change. You cannot make modifications that affect the terminal network.