File description

Function

The file description (FD) entry specifies the physical structure and the record names for a given file. A sort-file description (SD) entry provides information concerning the physical structure, identification, and size of the records on a sort-file.

A file description entry must be written for each file to be processed by the program. The information contained in this entry generally pertains to the physical aspects of the file, that is, the description of the data as it appears on the input or output medium.