An ISO image or .ISO file is a computer file that acts as an archive file, which is an exact copy of an existing file system. An ISO image is a type of disc image that contains the complete contents of a CD, DVD, or other disc or disk. An ISO file generally created via software application that will create, open, and extract CD or DVD image files. Then, convert the extracted image into an ISO file. It enables users to burn an exact copy of the original file onto a CD or DVD. The .iso is a file extension of ISO file. Furthermore, ISO images may also have UDF (Universal Disk Format) file system, which is used in Blu-ray discs and DVDs.
In binary format, an ISO image has copies of an optical media file system with the data. The data contained by ISO image is ordered on the basis of the file system, which is used on the optical disc. ISO image becomes smaller than the raw data on the optical media because it only stores data, disregarding control headers, and correction data.
Although the file extension .iso is commonly used, some ISO image files also contain .img file extension. Additionally, sometimes .udf extension is also used for indicating the file system is not ISO 9660, and it is UDF (universal disk format). The term ISO image is widely used to refer to any disc image file of an optical disc, as there is no single standard format.
The temporary storage is a common use for an ISO image; it creates an identical copy of the original disc before written to a blank CD-R or DVD-R. ISO image file contents may be copied to a local folder as these files may be opened. They may also be virtually accessed and mounted as a CD drive.