When you burn a CD or DVD, there are within it various files that make it up. The ISO image, therefore, is nothing more than the grouping of all these elements – including boots and attributes. A file of this type can be, for example, copied and burned to a CD or DVD, mounted in virtual form or extracted to the hard disk.
The great advantage of the ISO image is to be able to have access to the contents of a CD or DVD without the need of a physical media. Thus, it is possible to share software and even entire operating systems using a local area network or the internet – after all, today the vast majority of disc burning programs support this file type and it is easy to create a virtual environment to use it. It is also useful to back up the ISO of your physical media as a form of backup.
Different of the files .ZIP, the ISO image is not compressible. Thus, the file size will be exactly the one from the CD or DVD. ISO images are used by the Windows operating system, being that Mac OS X is compatible only with the CDR format, which has the same functions and features of ISO.
How to create and read an ISO image
An ISO image can be created from a physical media that already exists, or with a group of computer files. For both cases, you will need tools such as Free DVD ISO Burner and Free ISO Creator, both free.
Already to access this type of file without having to burn a CD or DVD, there are programs that create a virtual emulator for the ISO image. A good tip for this is to use the free software Virtual CloneDriver.