What is an ISO Image / .ISO File?
.ISO files are, in a sense, packed files containing entire CD or DVD images. Most burning software can take these files and burn them directly to a CD/DVD, making available the files within. These files are convenient when transferring CD or DVD information over the Internet, such as in the case of freeware operating systems. Microsoft has used ISO images to allow people to download trial copies of their operating systems and software, and many variants of Linux also use .ISO files to make full CDs available. Transferring .ISO files is more convenient than distributing the individual files within as they not only contain file information but also the files’ directory structure, boot data, and CD/DVD metadata such as the media’s author, copyright, and other information. And, while other file packing formats exist such as .ZIP and .RAR, using an .ISO file is more convenient as the file recipient does not have to take an intermediary step of uncompressing the file before writing a CD or D