What is ISO Image?

An ISO image (International Organization for Standardization) is an archive file (also known as a disc image) of an optical disc, composed of the data contents of every written sector of an optical disc, including the optical disc file system. ISO images can be created from optical discs, or can be used to recreate optical discs using ISO burning software from many software vendors. ISO image files typically have a file extension of .iso. The name ISO is taken from the ISO 9660 file system used with CD-ROM media.

Advantages of ISO image

As with any other archive, an ISO image includes all the data of files contained on the archived CD, DVD or Blu-ray Disc (BD), or any other disc format. They are stored in an uncompressed format. Moreover, any DVD can be archived by .ISO format by DVD to ISO ripping program. It is a true digital copy of the original.

Because the ISO image file is not stored in a container file, it is an attractive alternative to physical media for the distribution of software as it is simple to transfer over the Internet.

A feature of an ISO image is that it can be easily rendered, or "burned" to a DVD, or a BD by using ISO authoring or disc burning software. It can also be opened using any file archiver. ISO burning is now typically a native feature of modern home and business computer operating systems.

One of the other noticeable features of an ISO is that it can be "mounted" or be treated as a regular Compact Disc that would be inside a running computer. When an ISO is mounted, it acts as if a physical disc were loaded in the drive.

Disadvantages of ISO image

ISO images are not able to store and recreate CD-Audio discs, due to the fact that CD-Audio discs do not use a computer file system. CD-Audio discs are formatted in tracks, and the track numbers, index points and CD time code are encoded into the lead-in of the CD-Audio disc, and these reference points are found throughout the CD-Audio sub-channel. To store an accurate copy of a CD-Audio disc, a different image format must be used.

ISO images are also unable to store multi-track disc images. And another drawback of ISO image is that so far there is no "portable" programs for the Windows OS were known to exist that were capable of mounting ISOs on a USB flash ("thumb") drive or of reading them from such a drive.