An ISO image (as prescribed by ISO standard ISO 9660) is a file that represents a one-to-one copy of a specific computer filesystem, most widely used for the compact disc medium (i.e an entire CD or DVD-ROM).

The term "ISO image" or just "ISO" is sometimes used informally to refer to disk images in formats other than ISO 9660.

Many Linux, BSD, or other free operating systems are distributed for download using an ISO image; because it is a one-to-one copy, file permissions and other filesystem metadata are not lost in the transfer. Also, it is possible to loopback mount the image under many of these systems to access the individual files. The ISO 9660 is specified as read-only; currently you cannot modify the content when mounting an ISO file. The loopback mount gives you read access only. However, there are special tools that will allow you to modify an ISO file.

After downloading, one can burn this image to a CD. If the burned CD includes an operating system that doesn't need to be installed to the hard disk (this is, can be used from the CD), it is called a LiveCD. LiveCDs are bootable. Such an example of these are the Gnoppix, Knoppix, Mepis and Morphix Linux distributions.

See also

• Disk image
• Nero Burning ROM

External links

• Software for dealing with ISO images:
  • BurnAtOnce
  • MagicISO
  • WinISO
  • IsoBuster
• Burning ISOs with Nero Burning ROM
• LinuxISO FAQ
• Emulating and Burning Images with Alcohol 120%
• Creating a bootable CD-ROM
• http://wiki.debian.net/index.cgi?IsoImage