Overview
ISO/IEC 11694-4:2008 - "Identification cards - Optical memory cards - Linear recording method - Part 4: Logical data structures" specifies the logical layout and data structures required to ensure compatibility and interchangeability for optical memory cards that use the linear recording method. It defines how information is organized on the accessible optical area, how tracks and sectors are formatted, and how error detection/correction and data encoding are applied, in the context of ISO/IEC 11694 family and the base ISO/IEC 11693.
Key topics and requirements
- Logical format structure: Definition of the accessible optical area subdivided into guard tracks, format description tracks, test tracks, application description tracks and user data (application area).
- Track layout and numbering: Tracks are arranged in reverse order starting from a reference track. The standard provides example layouts for small, moderate and maximum data capacity cards in normal and high-density modes (e.g., nominal track counts such as 1000, 2583, 3425 and high-density variants).
- Track guides & tolerances: Track guide width (2.2 µm ± 0.5 µm), centre-to-centre spacing (12.0 µm ± 0.1 µm normal density; 7.5 µm ± 0.1 µm high density) and accumulated tolerance limits (≤ 0.01 % at 25 °C). Limits on guide breaks are specified.
- Guard tracks & reference points: Guard tracks, including a reference (last bottom) guard track, are defined to protect user data regions and establish positional references.
- Track components & sectors: Definitions for Track ID, preformatted track headers, sectors, sector code words and the minimum access unit (sector).
- Data encoding and EDAC: Specifies modulation codes (e.g., MFM‑RZ, NRZI‑RZ), error detection and correction concepts (EDAC, ECC) and interleaving strategies. References to specific codes such as BEST are included where relevant.
- Measurement and characteristics: Procedures for preformatted and written data measurement and characteristics are outlined to support interoperability and testability.
Applications and practical value
- Ensures interoperability between card manufacturers, drive makers and application providers using optical memory cards with linear recording.
- Enables consistent design for secure ID credentials, access-control and biometric cards where optical memory is used.
- Supports card issuance, drive firmware, testing laboratories and system integrators who require standardized track layout, error correction, and encoding rules.
- Useful for developing card initialization tools, test suites and data interchange formats that rely on ISO/IEC 11694-4 logical structures.
Related standards
- ISO/IEC 11693 - Optical memory cards - General characteristics (base document)
- ISO/IEC 11694‑1, ‑2, ‑3, ‑5, ‑6 - Other parts of the linear recording method family
- ISO/IEC 10373‑5 - Test methods for optical memory cards
Keywords: ISO/IEC 11694-4:2008, optical memory cards, linear recording method, logical data structures, track layout, track guides, EDAC, MFM‑RZ, NRZI‑RZ, BEST code, sectors, ISO/IEC 11693.
Open preview (PDF)Identification cards — Optical memory cards — Linear recording method — Part 4: Logical data structures