Overview
ISO/IEC 9293:1994 - "Information technology - Volume and file structure of disk cartridges for information interchange" defines a standardized volume and file layout for disk cartridges used to exchange data between information processing systems. It supersedes the 1987 edition and extends support to a wider range of media (Flexible Disk Cartridges - FDCs - and, in most descriptions, Optical Disk Cartridges (ODCs)). The standard specifies recorded descriptors, file locations, attributes and an optional record structure while deliberately not prescribing the internal content or organization of individual files.
Key topics and requirements
- Volume and area layout: Defines the arrangement of a disk into a System Area and Data Area, physical and logical addressing, clusters and cluster status.
- Descriptors: Mandates an FDC Descriptor and an Extended FDC Descriptor to identify media attributes, volume label, file system type and other metadata needed for interchange.
- File Allocation Table (FAT): Specifies FAT format rules, entry sizes and recorded forms used to locate clusters and manage file allocation independent of the number of files on a volume.
- Directories and entries: Standardizes root directories, directory entry formats (name, extension, attributes, timestamps, starting cluster, file length) and special entries (volume label, sub-directory pointers, unused/never-used markers).
- Record structure (optional): Provides an optional model for file records supporting fixed-length, variable-length and segmented records, plus attributes for record-structured files.
- Defect and free space handling: Specifies locations and descriptors for defective space and unused recording space.
- Conformance: Defines conformance criteria both for recorded FDC media and for information processing systems (originating vs. receiving systems) that create or consume compliant cartridges.
Practical applications - who uses it
- Operating system and file system developers implementing cross-platform removable-media interchange.
- Storage hardware and media manufacturers producing FDCs/ODCs and firmware that must support standardized descriptors and FAT implementations.
- Software integrators and data-exchange tool vendors building import/export utilities for archived or portable data sets.
- Organizations exchanging archival, transactional or small-file collections that require interactive updates and multiple-file interchange without predefining file counts or sizes.
- Test labs and compliance auditors verifying media and system conformance to interchange requirements.
Related standards
Keywords: ISO/IEC 9293:1994, disk cartridges, FDC, ODC, file structure, volume structure, File Allocation Table (FAT), descriptors, information interchange, record structure, interoperability.