Overview
ISO/IEC 8211:1994 - "Information technology - Specification for a data descriptive file for information interchange" - defines a media‑independent interchange format to support moving files or parts of files containing data records between computer systems. The standard specifies the structure and semantics of a data descriptive file (DDF) and its data descriptive record (DDR) to describe user data fields, arrays, vectors and hierarchical structures containing character strings, bit strings and numeric data. It replaces the 1985 edition and includes support for FTAM document types.
Key topics and technical requirements
- File and logical record structure: clear separation of media records, interchange logical records, leaders, directories and field areas to enable robust parsing across platforms.
- Logical record leader fields: mandatory leader elements such as record length, leader identifier, version number, base address of field area, and entry map (sizes for field length/position/tag).
- Directory and field areas: directory entries that identify field tags, lengths and positions; field areas that contain DDR and data records (DRs).
- Data descriptive fields: multi‑level descriptions (three interchange complexity levels) that define elementary and compound fields, array descriptors, subfield/vector labels, and format controls.
- Data types and structures: standardized description of character strings, bit strings and numeric forms, including storage order and concatenated structures.
- Character set handling: mechanisms to announce and use coded character sets (ISO 2022 extensions and ISO/IEC 10646), including file‑wise and field‑wise defaults and announcer sequences.
- FTAM integration and ASN.1: Annexes register abstract/transfer syntaxes and define FTAM document types (unstructured and structured), with implementation guidance for operations such as EXTEND and REPLACE.
- Conformance and application controls: reserved tags, special field tags (file control, record identifier, user application), and field control lengths for interoperability.
Applications and who should use it
ISO/IEC 8211 is practical for organizations and professionals who need reliable, platform‑independent data interchange:
- Software developers and systems integrators building import/export tools or middleware for heterogeneous systems.
- Data architects and engineers who must describe complex record formats (arrays, nested structures, vectors).
- Archivists and data custodians exchanging structured datasets between archival and operational environments.
- Standards implementers working with FTAM (ISO 8571) or with international character encodings (ISO 2022, ISO/IEC 10646).
Related standards
- ISO 2022 - coded character set extension mechanisms referenced for multi‑byte and escape‑based encodings.
- ISO/IEC 10646 - universal character set support announced by ISO/IEC 8211.
- ISO 8571 (FTAM) - FTAM document types and operations are described for interoperability with ISO/IEC 8211.
- ASN.1 registrations and FTAM mappings are provided in the standard’s annexes for implementers.
Keywords: ISO/IEC 8211:1994, data descriptive file, data interchange format, DDR, logical record, ISO 2022, ISO/IEC 10646, FTAM, data descriptor.