For convenience, the non-interactive gen option can also create empty sequential and relative files if they are missing. The entry contains only three fields. The first field is the file name. The second field is the record size, and the final field is an S for a sequential file or an R for a relative file. The record size field is only comment, so it can be set to any numeric value.
Whether to use gen or a COBOL program to create the data files for an application depends on which is more convenient. Creating the file list can be painstaking, but the symbol table listing of the compiler can help to compute the size information. Once the files are created, however, it is easier to replace missing files this way than with a program that must explicitly test for a file's existence before creating it.