What is an ISO Image?

What is an ISO Image?

In the context of files an "image", is simply a file that can be used as a virtually identical copy of the original media. This file not only contains individual data files; it also contains track and sector information and arranges all this information in a file system, just like disk media. Image files, unlike normal files, are usually not opened; rather, they are mounted.

An ISO image is simply a CD-ROM or DVD image saved in ISO-9660 format used with CD-ROM media, but what is known as an ISO image might also contain a UDF file system or a DVD or Blu-Ray Disc (BD) image.

ISO images are mainly used as source files from which to create media. As an example, most distributions of Linux release ISO images of the installation media. These images are usually available from anonymous FTP servers.  After you download the image, you can use CD-burning software to recreate the physical CD-ROM/DVD install media.

ISO images are not stored in a compressed format. 

Any file with an extension of .ISO format is a true digital copy of the original. The ISO image file is not stored in a container file. An .ISO image can be transferred to any data storage device. An “valid” ISO image is not a compressed collection of various files, however it is an uncompressed gathering of different files incorporated into one single file.

An ISO image can be burned, to a CD, DVD, or BD by using disc burning software. It can also be opened using any file extraction software. ISO burning is now typically a native feature of modern home and business computer operating systems.

Hybrid Disc formats includes the ability to be read by different devices, operating systems, or hardware. A nice example off this could be the release of hybrid ISO files that can be booted or started from both BD or DVD and USB Flash Drives devices when the image is written to any of these storage devices.