ISO 9660 is a file system standard for optical media, such as CD-ROMs, DVDs, and Blu-ray Discs. It is a read-only file system, meaning that files cannot be created or modified on a disk that uses the ISO 9660 format. SO 9660 was first published in 1988 and has been revised several times since then. The current version is ISO 9660:2019.
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1. History ISO 9660 Specification
ISO 9660 was first published in 1988. It was originally developed by the High Sierra Group, a consortium of computer manufacturers and software developers. The standard was adopted by the International Organization for Standardization (ISO) in 1989.
The ISO 9660 specification, officially titled “Information technology — Volume and file structure of CD-ROM for information interchange”, defines the file system layout and organization of data on CD-ROMs and other optical media. It was developed by the International Organization for Standardization (ISO) and published in 1988.
2. File System Features ISO 9660 Specification
- Limited file names: File names are limited to 8 characters followed by a 3-character extension, similar to the DOS file naming convention.
- Case insensitive: File names are case insensitive, meaning uppercase and lowercase versions of the same filename are considered the same.
- Limited support for special characters: Only a limited set of special characters are allowed in file names.
- Limited file attributes: Supports basic file attributes like read-only and hidden, but lacks more advanced attributes like creation date and owner.
- Maximum file size: The maximum file size is limited to 4GB.
3. Extensions and Variations ISO 9660 Specification
- Rock Ridge Interchange Protocol (RRIP): Extends ISO 9660 with support for longer file names, case sensitivity, and additional file attributes.
- Joliet Extension: Adds support for Unicode file names, allowing for easier interaction with non-English operating systems.
- UDF (Universal Disk Format): A more modern file system format for optical media, offering greater flexibility and features compared to ISO 9660
4. Limitations ISO 9660 Specification
- Limited features: Lack of support for advanced file system features compared to modern formats.
- Performance limitations: Can be slower than other file system formats, especially for large files.
- Restrictions on file names: Can be cumbersome for storing files with long or complex names.
Overall, ISO 9660 remains a relevant file system format for optical media due to its simplicity, platform independence, and wide support. However, for applications requiring advanced features or larger file sizes, newer formats like UDF are preferred.
5. Specification ISO 9660
ISO 9660 specifies the following elements of an optical disc file system:
- File names: File names are limited to 8 characters for the filename and 3 characters for the extension.
- File sizes: File sizes are limited to 4 GB.
- Directory structure: The directory structure is a simple tree structure with a root directory and subdirectories.
- Data blocks: Files are stored in data blocks that are 2048 bytes in size.
6. Extensions ISO 9660 Specification
ISO 9660 has been extended by a number of standards, including:
- Rock Ridge Interchange Protocol (RRIP): RRIP adds support for longer file names, long filenames, and extended attributes.
- ISO 9660 Joliet: Joliet is a Unicode-compatible extension of ISO 9660 that allows for longer file names.
- ISO 9660 Rock Ridge/Joliet: This extension combines the features of RRIP and Joliet.
ISO 9660 is the most common file system used for optical discs. It is used to store a wide variety of data, including operating systems, software applications, and multimedia files.
ISO 9660 is a simple and efficient file system that is well-suited for optical discs. It is a widely used standard that is supported by a variety of operating systems and software applications.
