Direct access

Using direct access, the records of an external file can be read or written in any order. The records must be either all formatted or all unformatted. The records must not be read or written using sequential or stream access, list-directed or namelist formatting, or a nonadvancing input/output statement. If the file was previously connected for sequential access, the last record of the file is an endfile record. The endfile record is not considered a part of the file connected for direct access.

Each record in a file connected for direct access has a record number that identifies its order in the file. The record number is an integer value that must be specified when the record is read or written. Records are numbered sequentially. The first record is number 1. Records need not be read or written in the order of their record numbers. For example, records 9, 5, and 11 can be written in that order without writing the intermediate records.

All records in a file connected for direct access must have the same length, which is specified in the OPEN statement when the file is connected.

Records in a file connected for direct access cannot be deleted, but they can be rewritten with a new value. A record cannot be read unless it has first been written.