Data-set parameters are used to specify SAS datasets (a.o. FITS files).
The parameter may specify an absolute or relative path. For example:
bar.FIT
../foo/bar.FIT
/data/foo/bar.FIT
There are additional parameter types which allow components of a dataset, such as blocks,tables, arrays and columns to be specified (see below).
The SAS GUI provides a special browser for examining and selecting datasets and their components.