See Sort Information for details. This information differs depending on the operating environment. Variable is the name of each variable. By default, variables appear alphabetically. Variable names that contain an underscore and digits may appear in a nonstandard sort order.
Type specifies the type of variable, character or numeric.
Pos specifies the starting position of each variable in the observation. If none of the variables in the SAS data set has a format, informat, or label associated with it, the column for that attribute does not appear. The section shown in Index Attributes Section appears only if the data set has indexes associated with it. Index displays the name of each index. For simple indexes, the name of the index is the same as a variable in the data set.