ISO 9660, established by the International Organization for Standardization (ISO), has significantly influenced how we organize and access data on storage media, particularly compact discs (CDs). Although the CD drive has declined, the ISO 9660 file format and its derivatives are still relevant, especially with ISO images that store files ontop-of-the-line flash drivesandhard disks.
This article explores the origins, attributes, and constraints of the ISO 9660 standard, highlighting its impact on cross-platform compatibility and the concept of ISO images.
What is ISO 9660?
ISO 9660 is a standard way of organizing files, primarily on CDs and other types of discs like Blu-ray discs and digital versatile discs (DVDs), published by the ISO. It’s like a set of rules everyone follows so that these discs can be created with common software programs and work on all kinds of computers. The files can also be stored on USB memory sticks and hard disks.
The standard works with several operating systems, including Windows, macOS, and Unix. While modern computers hardly come with CD drives, back in the day, if you wanted your CD-ROM or DVD to work on any computer, you needed to use ISO 9660 or something similar like the Joliet format, a modern extension of ISO 9660 or the newer Universal Disk Format (UDF) by the Optical Storage Technology Association (OSTA).
History and development of ISO 9660
CDs were created for music but became popular for storing other digital data. However, there were no clear rules for organizing this data, so each CD maker did it differently. To fix this, major tech players like Apple, Sony, and Microsoft came together in California to create a proposal in 1985. They called it the High Sierra Format, a system that organized files in a structured way, kind of like a tree with branches.
The proposal was sent to the European Computer Manufacturers Association (ECMA), which made some changes. The result was a standard called ECMA-119 in 1986. This standard was then sent to the ISO, where it was reviewed and became the ISO 9660 standard in 1988. Rather than alter the core of the High Sierra Format, the changes brought by ISO 9660 made the standard adaptable to countries outside the United States. So, ISO 9660 became the standard way to organize data on CDs.
In 2013, the ISO made some updates to ISO 9660. They changed how data was structured and how file names were used to make the standard more compatible with the Joliet extension. In 2017, they released another version of ECMA-119 that’s the same as ISO 9660. This way, people worldwide can share and use computer files easily, no matter what kind of computer they have.
Directory and files of ISO 9660 standard
To understand directories and files in ISO 9660, think of a big library. Files and folders are like books on shelves, and you may identify them by looking at a special tag on the shelf called the file attribute. On the other hand, directories are the shelves, and they contain specific files. To find a file, look at the labels on the shelves (directories) and follow them to the right shelf. There’s also a list of all the shelves (directories) in the library, telling you where each one is located.
ISO 9660 has three levels:
Other restrictions specify that you can’t have more than eight hierarchical directories, and the path to any file can’t be longer than 255 letters. Also, file names must take one period only, while directory names do not use periods at all.
Features of ISO 9660
ISO 9660 is popular because it’s simple and works on many computers. As a result of this cross-platform compatibility, it only has a few features. Here are the main ones:
Limitations of ISO 9660
While its simplicity is a plus, it has a few limitations. The most notable ones are:
What is an ISO image?
An ISO image is a special way of organizing data on a disc. It’s a big electronic copy of a CD or DVD, including all the folders and files on it. Since it takes a picture of everything on the disc, you can copy it exactly the same way to another disc.
People use ISO images to share things like computer programs over the internet to be burned on discs. However, these files can be stored on more reliable devices like USBs and hard drives. It keeps all the files organized like they were on the original disc and ensures nothing gets messed up.
ISO 9660: The unsung hero of digital disc organization
ISO 9660 addressed the chaotic variability in organizing data on optic discs by creating a unified set of rules. It also revolutionized data storage for physical media and paved the way for ISO images, allowing data preservation and sharing beyond the now-dying optical discs. To learn about more file formats, see our article on theHEIC file for storing images.
