When you specify the characteristics of a region you use the Parameter Groups menu. This can be accessed using shortcut /PARM or menu command =A.C.P. Here you can review and change a large number of parameters. They are grouped into Categories to make it easier to maintain them. All of these parameters are stored in the VFS Dataset. They are read and processed at startup time of the Region.
But what if you want to make sure to start the region with the same Parameter settings every time? What if you have several regions which should use the same specifications (except of those which have to be unique)?
In this case you can use an INIFILE containing values for all Parameters and is read during start of the region. You create that file using shortcut /CUSTOM, then select Option G or by entering command =A.C.G. In the panel "Customizer : Generate INI Procedure" you specify the member name in which the Parameters are to be stored. Pressing PF6 twice creates the INI file.
You can use this file at startup time by changing in the RUNSYSIN-member the default entry.
where <name_of_member> is the name of the member containing the INIFILE.