Overview
ISO/IEC 13421:1993 - "Information technology - Data interchange on 12,7 mm, 48-track magnetic tape cartridges - DLT 1 format" defines the physical, magnetic and logical characteristics required to enable reliable interchange of 12.7 mm (0.5 inch), 48-track magnetic tape cartridges using the Digital Linear Tape 1 (DLT 1) format. The standard covers tape construction and dimensions, signal quality, a recording method and the DLT 1 data format. Together with labelling standards (for example ISO 1001) it enables full data interchange between generating and receiving systems.
Key topics and requirements
- Physical and mechanical characteristics: base film material, tape width (12.7 mm), coating thickness, total tape thickness, curvature and layer-to-layer adhesion, abrasivity, light transmittance and dimensional stability.
- Magnetic and recording characteristics: physical recording density (document reference at 1 674 ftpmm), flux transition spacing, average signal amplitude (SRA), overwrite and peak-shift behaviour, and test/current calibration (Standard Reference Current / Test Recording Current).
- Tape format and layout: Reference Edge definition, recording direction, tape layout zones such as Scratch Area, Calibration Tracks (forward/reverse), Guard Areas, Directory Area and Data Area with physical and logical track mapping (logical tracks = pairs of physical tracks).
- Data structure and error control: Logical Blocks, Data Blocks, Entities (groups of logical blocks), preamble/sync/data fields, Control Fields (CF1, CF2), CRC (64-bit character) and Error-Detecting/Correcting Codes (EDC/ECC) for integrity and recovery.
- Conformance, environment & safety: conformance criteria for tapes, generating and receiving systems; environmental and conditioning ranges for testing and operation (e.g., test temp ~23 ±2 °C; operating temp 10–40 °C; storage and archival recommendations); safety and flammability requirements.
- Test methods & annexes: measurement methods and informative annexes covering light transmittance, CRC/ECC generation, control field formats, transportation and handling recommendations, inhibitor tape guidance and durability tests.
Applications and who uses it
- Tape manufacturers and magnetic media suppliers - to produce cartridges that interoperate across vendors.
- Tape drive and recorder designers - to implement read/write electronics, calibration and error-control consistent with DLT 1.
- System integrators, data centers and archival services - to ensure data interchangeability, long-term storage and recovery using 12.7 mm, 48-track DLT 1 tapes.
- Test laboratories and standards compliance teams - to certify tapes/drives to ISO/IEC 13421 conformance and perform environmental/quality tests.
Related standards
- ISO 1001 - file structure and labelling of magnetic tapes (labelling referenced for interchange).
- ISO/IEC 9661 and ISO/IEC 11559 - earlier 12.7 mm tape interchange standards (different cartridge/format types).
- ECMA-182 - original ECMA specification from which ISO/IEC 13421 was derived.
Keywords: ISO/IEC 13421:1993, DLT 1 format, 12.7 mm magnetic tape, 48-track cartridge, data interchange, tape format, CRC, ECC, Standard Reference Amplitude, tape testing.