Position
Position specifies the record number of the first record to be written relative to the beginning of the file (record 1). The next sequential record is written if position is not specified or if 0 is specified (0 is the default).
If a file has fixed-length records, you can write a record beyond the current last record, including a record with a position number more than one greater than the number of the last record. If the skipped records are not written before the file is closed, the file is termed a sparse file. A skipped record may be written when the file is subsequently reopened. If a skipped record is read, it is retrieved as allX'00' bytes.