The processing of SMP/E commands requires a variety of data sets. You can either provide the DD statements for these data sets (such as in a cataloged procedure) or have SMP/E allocate the data sets dynamically. Dynamic allocation has the advantage that data sets are allocated only as they are needed; DD statements must successfully allocate all data sets, regardless of whether they are needed for the command being processed.

There are some drawbacks to using DD statements. For example, all the data sets defined by DD statements must be successfully allocated, regardless of whether they are needed for the command being processed. In addition, if you are running several SMP/E commands, you must be careful to use the correct DD statements for each command. If you are processing zones that are in different CSI data sets, you must make sure to provide a DD statement that points to each of those zones and their associated CSIs.

With dynamic allocation, you do not have these problems. Subsequent topics describe the sources from which SMP/E can get the information it needs to allocate data sets dynamically and how it chooses which of these sources to use.