4.6. Major sources of VSAM processing options
The VSAM cluster processing options and characteristics come from different sources, for example, JCL, SMS data classes, or macro parameters. The source of the processing options can be confusing since the same parameter can be specified in more than one source. In this case, there is an order of precedence that, when not understood, may give logically unexpected results. Table 4-3 lists the processing options and the characteristics and their sources, indicating the precedency by the highest number. The underlined value in MACRF indicates the default. The Type explains if the parameter is related to a data set characteristic (C) or processing option (P).