Overview
ISO/IEC 14840:1996 - Information technology - 12.65 mm wide magnetic tape cartridge for information interchange - Helical scan recording - Data‑D3‑1 format - defines the physical, magnetic and recording-format requirements needed for interoperable 12.65 mm magnetic tape cartridges. The standard specifies cartridge mechanical dimensions, unrecorded tape mechanical/magnetic characteristics, and the helical-scan Data‑D3‑1 recorded format (packets, scan groups, time code, servo and track geometry) so that cartridges can be exchanged and read between compliant drives.
Key facts:
- Media: 12.65 mm (approx. 1/2 in) magnetic tape cartridge
- Defined cartridge Types: Type A (≈91 m, 10 GB), Type B (≈204 m, 25 GB), Type C (≈392 m, 50 GB)
- Recording: Helical scan, includes packet/scan-group layout, CRC/ECC protection and servo/time-code tracks
Key topics and technical requirements
The standard covers both physical and logical layers for reliable interchange:
- Cartridge mechanical specs - case dimensions, leader block, reel hub, write‑protect, notches and label areas to ensure physical interchangeability.
- Unrecorded tape properties - tape width/length, thickness, curvature, surface roughness, adhesion and tensile strength requirements.
- Magnetic recording characteristics - signal amplitude, resolution, narrow-band SNR, ease of erasure, missing-pulse metrics and test conditions.
- Track geometry & recording method - helical track width, pitch, azimuth angles, bit-cell length, bit shift, and long/short-term density definitions.
- Format & error control - Packet format, Packet ID (including algorithm registration), Packet Trailer, Scan Group structure, Helical Time Code (HTC), CRC characters and layered ECC (inner/outer).
- Servo and Time Code tracks - layout, polarity, read amplitude and quality criteria for track following and addressing.
- Conformance rules - compliance requires meeting specified clauses for cartridge (clauses 4, 7–10), recording (clauses 11–16) and including registered algorithm identification when used.
- Tape drive and media manufacturers implementing compliant 12.65 mm helical-scan products for cross-vendor interchange.
- Data center and archival managers ensuring long-term, portable backups and migrations across systems.
- Software and firmware developers for tape controllers, formatters and error‑correction implementations.
- Test labs and quality assurance organizations validating media and drives to the standard’s mechanical, magnetic and signal-performance tests.
Practical uses include standardized backups, archival exchange between institutions and vendor-neutral data migration.
Conformance & related standards
- Claims of conformance must state cartridge Type and implemented registered algorithms (registration per ISO/IEC 11576:1994).
- Normative references in ISO/IEC 14840 include standards for material tests and safety (e.g., ISO/R 527, ISO 1302, ISO 683‑13, IEC 950).
- Annexes provide measurement procedures, handling/transportation guidance and CRC/ECC generation details for implementation and testing.
Keywords: ISO/IEC 14840:1996, 12.65 mm magnetic tape, magnetic tape cartridge, helical scan recording, Data‑D3‑1 format, tape interchange, packet format, ECC, CRC, tape drive conformity.