For fixed-width flat files, data in a row can be shorter than the row length in the following situations:
The file is fixed-width line-sequential with a carriage return or line feed that appears sooner than expected.
The file is fixed-width non-line sequential, and the last line in the file is shorter than expected.
In these cases, the Integration Service reads the data but does not append any blanks to fill the remaining bytes. The Integration Service reads subsequent fields as NULL. Fields containing repeating null characters that do not fill the entire field length are not considered NULL.