To select the data element size for the list structure, you need to understand the approximate sizes of the smallest and largest pieces of data to be stored in the list entries. If the data can fit into adjunct areas, you could avoid using data entries altogether. Code a value of 0 for ELEMENTRATIO to define a list structure without data entries. The system ignores the MAXELEMNUM parameter if you specify it with an ELEMENTRATIO of 0.

The system allows a maximum of 16 data elements per data entry (with CFLEVEL=0) or 255 data elements per data entry (with CFLEVEL=1 or higher), but you can use the MAXELEMNUM parameter to specify a smaller maximum number if you want to further restrict the size of the largest data entries. In all cases, whatever value you choose for MAXELEMNUM, the maximum size of a data entry is 64K.

The data element size multiplied by the maximum number of data elements must be sufficient to accommodate the largest piece of data that you need to manipulate as a single entry. See Table 1 for a list of data element sizes.