UNLOAD PLUS requires this data set if you specify the INFILE option to unload from a VSAM linear data set instead of Db2 table space.
You can use either the default ddname (VSAMDD) or a ddname that you specify by using the INFILE VSAMDDPREFIX command option. Use the VSAMDDPREFIX option if you are unloading a partitioned object with more than 99 partitions.
For multiple partitions, add the partition number as a suffix to the ddname that you specify in your JCL.
Warning
Unpredictable results can occur if the data sets do not match the options that you specify in the INFILE command option.