The basis of the ISO file format is the ISO 9660 standard, published by the International Organization for Standardization (ISO) in 1988. This standard was developed to define the file system used on CD-ROMs. Its goal was to ensure a common disk structure across different computer systems (e.g., MS-DOS, UNIX, macOS). With the widespread use of computers with CD-ROM drives in the 1990s, the ISO format gained an important place in software and game distribution. Over time, the use of DVDs and USB devices increased, and the ISO format began to be used in these media as well. Today, ISO has become a format that reduces the need for physical media, especially in digital software distribution.

Technical Specifications and File Structure

An ISO file is a digital image of an entire physical disk. This image contains not only the data but also the file system, directory structure, boot partitions, and error control codes. The ISO format is generally read-only and does not allow editing of the content. Access to the content is achieved through virtual disk drives or by burning the data to physical media. ISO files are structured to maintain data integrity and standardize installation processes.

Uses

ISO files are most commonly known as installation media for operating systems. For example, Windows, Linux, and macOS installation discs are typically provided in ISO format. Many software developers also prefer the ISO format when distributing their programs. Educational content, games, system backups, and live CD/DVD media can also be stored in ISO format. This structure simplifies file transfer and maintains the integrity of the content.

Standards and Compatibility

ISO files offer broad platform compatibility because they are based on the ISO 9660 standard. This standard has been expanded over time with extensions such as Joliet (an extension developed by Microsoft), Rock Ridge (for UNIX systems), and El Torito (for bootable disks). This has made ISO files readable by a variety of operating systems. Today, many software and hardware directly support the ISO format.

Access Methods and Burning

There are two main ways to access ISO files: mounting (using a virtual drive) and burning to physical media. Modern operating systems (e.g., Windows 10+, Linux distributions) offer support for directly mounting ISO files. Alternatively, users can create bootable media by burning these files to a USB stick or DVD. This feature is particularly useful for system repairs and clean installs.