Overview
ISO/IEC 11559:1993 - "Information technology - Data interchange on 12,7 mm wide 18‑track magnetic tape cartridges - Extended format" defines physical, magnetic and logical requirements for interchange of data recorded on 12.7 mm (0.5 in) wide, 18‑track magnetic tape cartridges in an extended format. It incorporates the cartridge and recording method of ISO 9661 and adds extensions to increase tape utilization (extended blocks) and to identify whether data has been processed by registered algorithms. The standard enables reliable cross‑vendor interchange, calibration traceability (Master and Secondary Reference Tapes), and full data interchange together with ISO 1001.
Key topics and technical requirements
- Physical & mechanical characteristics: tape material, width (12.7 mm), track geometry (18 tracks), cartridge case dimensions, reel characteristics and environmental/storage/transportation recommendations.
- Magnetic & recording characteristics: physical recording density, bit‑cell length (short‑ and long‑term averages), flux transition definitions, read signal amplitude, overwrite and resolution.
- Track & tape format: track positions, azimuth, density identification burst, interblock gaps, erase gaps, tape marks, preamble/postamble, and first/last recording rules.
- Data structures & formatting: Packets, Packet Identifier (32 bytes), Packet Trailer, Data Blocks (concatenated packets), Logical/Host/Processed/User Data Records, and rules for combining smaller packets into extended blocks.
- Error control: Error Correcting Code (ECC) mechanisms including Diagonal Redundancy Check (DRC) and vertical redundancy checks; Cyclic Redundancy Check (CRC) characters for error detection.
- Processing & algorithm registration: methods to indicate processed data and the registered algorithm ID (stored in Packet ID Byte 13). If algorithm unregistered, byte set to FE. Receiving systems must recognize extended blocks and be able to restore processed data for registered algorithms.
- Calibration & reference: Standard Reference Amplitude (SRA), Standard/Test Recording Current and reference tapes (Master and Secondary SRM 3202).
Applications and who uses it
- Tape drive and media manufacturers implementing 12.7 mm, 18‑track cartridge drives.
- Data center and archival storage engineers ensuring cross‑vendor data interchange and long‑term retention consistency.
- Embedded system and tape controller developers implementing packet formats, ECC and algorithm handling.
- QA, calibration and test laboratories using Master/Secondary reference tapes to validate amplitude, resolution and overwrite.
- Standards bodies and system integrators aligning legacy or migration solutions with ISO 9661 compatibility.
Related standards
- ISO 9661 - base format for 12.7 mm cartridges (M‑tracks)
- ISO 1001 - file structure and labelling for magnetic tape interchange
- ISO/IEC 11576 - registration procedure for lossless compression algorithms
Keywords: ISO/IEC 11559:1993, 12.7 mm wide 18‑track magnetic tape cartridges, extended format, data interchange, tape format, packet format, ECC, CRC, magnetic tape standard.