To create a new format,
specify a valid libref as the value of the LIBREF= option. Specifying
a valid libref creates a new format in the SAS 9 style in the FORMATS
catalog. The FORMATS catalog is stored in the SAS library that is
identified by the LIBRARY= option.
Beginning with SAS 9,
you can no longer write Version 5 formats to a load library by using
a ddname as the value of the LIBRARY= option. You can read Version
5 formats, but you cannot write them.