Overview
ISO/IEC 11557:1992 specifies a 3.81 mm wide magnetic tape cartridge format for information interchange using helical-scan recording - the DDS-DC (Digital Data Storage - Data Compression) format for 60 m and 90 m tapes. The standard defines the physical and magnetic characteristics of the cartridge and tape, the quality and method of recording, and the recorded format required to ensure reliable data interchange between compliant drives and systems. Two cartridge/tape types are defined: Type A (nominal 13 µm tape, up to 60.5 m) and Type B (nominal 9 µm tape, up to 92.0 m).
Keywords: ISO/IEC 11557, DDS-DC, 3.81 mm magnetic tape cartridge, helical scan, data interchange, Type A, Type B.
Key topics and requirements
- Physical cartridge and tape specifications
- Case dimensions, lid mechanisms, hub interfaces, label areas and optical detection for beginning/end of tape.
- Tape mechanical properties: width (3.81 mm), thickness, leader/trailer lengths, tensile strength, curvature, coating adhesion.
- Magnetic recording characteristics
- Specified signal amplitude, overwrite behavior, ease of erasure, missing-pulse tolerance and S/N requirements.
- Track geometry and recording densities with helical-scan track layout and azimuth considerations.
- Recorded format (DDS-DC)
- Logical layout: Device Area, Reference Area, System Area, Data Area, EOD and Post-EOD Areas.
- Support for Single Data Space and Partitioned tapes; housekeeping frames (system log, tape management), repeated frames, ECC3 frames.
- Processing and interchange controls
- Processed vs unprocessed data, Entities, Codewords and Processing Algorithms (e.g., compression).
- Algorithm registration requirement: implemented Processing Algorithms must be registered and referenced on tape.
- Conformance levels defined for cartridges, generating systems and receiving systems; handling of appending, overwriting, Read-After-Write, and reprocessing capabilities.
- Environment & safety
- Test, operating, storage and transport conditions; safety/flammability notes.
Applications and who uses it
- Primary uses: backup, archival and data interchange between tape drives in enterprise and professional IT environments.
- Who uses the standard: tape cartridge manufacturers, tape drive designers, tape media test laboratories, storage integrators, data center operations, software vendors implementing tape I/O, and standards/compliance teams.
- Benefits: ensures mechanical compatibility, predictable recording performance, and software-level interoperability (including compressed/processed data interchange) across vendors.
Related standards
- ISO/IEC 10777 - DDS format (baseline DDS features referenced in ISO/IEC 11557)
- ISO/IEC 11576 - Procedure for registration of algorithms for lossless data compression
- IEC 950 - Safety of information technology equipment
ISO/IEC 11557 is intended for implementers and purchasers who require reliable, cross-vendor magnetic tape interchange using the DDS-DC helical-scan format.