By Mara Shannon

ISO, BIN and DAA are three different file formats for storing disc images, or virtual copies of physical discs. ISO is the most common of the three formats, while DAA is the least common. Each format has advantages and disadvantages.

Disc Images

Disc images are copies of optical media -- CDs and DVDs -- that are saved as files on your computer's hard drive. These files can serve as backups if the original disc is damaged or lost. It's also possible to use the disc images by mounting them on a virtual CD/DVD drive, which makes your computer treat the disc image file as if it were a physical disc in a physical disc drive. This way you can use the disc without causing wear or damage to the physical CD or DVD.

ISO Files

The ISO format is based on the ISO-9660 standard created by the International Organization for Standardization, an organization which develops international standards in across many different fields. ISO files contain a copy of the data on the disc as well as information about the disc's structure, such as file headers. Because the ISO format is so widespread, it's easy to find free programs to create and open them, which means you won't lose access to your data just because you lost access to a commercial disc image program.

BIN Files

The file extension BIN stands for "binary." A BIN disc image file contains the data from a disc stored in binary format. A BIN file does not usually contain information about the disc's contents, like an ISO file does. Instead, it saves this information in a separate file with the same file name but a different extension -- usually CUE. Fewer programs can open BIN files than can open ISO files, but you can sometimes open BIN files with a program that can read ISO files if you change the BIN extension to ISO.

DAA Files

The file extension DAA stands for "Direct-Access-Archive." DAA is a proprietary format created for PowerISO. A proprietary format is exclusive to a particular company or program; this means very few programs can open or convert DAA files compared to BIN or ISO files. However, DAA files have some advantages: you can add passwords to protect sensitive information, compress them so they take up less disc space, and split them into multiple parts.