From Widipedia..

An ISO image is an archive file (a.k.a. disk image) of an optical disc using a conventional ISO format that is supported by many software vendors. ISO image files typically have a file extension of .ISO but Mac OS X ISO images often have the extension ".CDR". The name "ISO" is taken from the ISO 9660 file system used with CD-ROM media but the term ISO image can refer to any optical disc image, even a UDF image.

ISO image
File extension = .iso
Uniform Type Identifier = public.iso-image
Type of format = Disk image

Format

In addition to data files it also contains all the filesystem metadata, including boot code, structures, and attributes. All of this information is contained in a single file. It is not a multi-track image format and thus cannot be used for Audio CDs

These properties make it an attractive alternative to physical media for the distribution of software as it is simple to transfer over the Internet or via a LAN connection.

Typical uses

Some of the common uses include:

• distribution of software
• mount "virtual drives" which emulate physical CDs or DVDs. Better performance is achieved by running an ISO image since hard drive I/O speed is many times faster than a CD/DVD drive.
• To use software titles that are written in such a way that they require a physical disk to be present in order to run. Games are commonly in this category.
  

• Most optical disc authoring software (CD burners) can write ISO files to disc.
• See List of ISO image software for a list of software programs that can read and/or write ISO image files.
  

• BIN/CUE
• BWT, BWI, BWS, BWA
• CCD
• CIF from Adaptec Easy CD Creator.
• CSO (.cso)
• DAA (.daa)
• LCD from CDSpace
• MDF/MDS (.mdf)
• NRG (.nrg)
• DMG (Apple disk image) (.dmg)
• UIF (Universal Image Format) (.uif)
• IMA (.ima)
• IMG (.img)
• .dk (.dk)
• WIM (.wim)
  

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