Files with the extension ISO are a commonly used file type but I get a lot of inquiries from PC users who do not know what an ISO file is or what to do with one. If you are puzzled by ISO files, here’s what they are all about.
ISO files are simply a way of packaging a lot of files and folders together into a single file with the file extension ISO. They are generally used to create an image of a CD or DVD. Having just one file containing everything is convenient for downloading or for storing on a computer. It is becoming common to distribute programs this way instead of providing physical media. As fewer devices are coming with optical drives, you are likely to encounter ISO files more and more.
A major reason that many average PC users have trouble with ISO files is that Windows XP and Vista do not recognize them natively. If you try to open an ISO file in these older versions of Windows, they do not know what to do with it unless you have installed some third-party software to manage ISO files. However, Windows 7 does have a feature to burn ISO files to a CD or DVD.
Burning ISO files to a CD/DVD
One way to make use of ISO files is to burn the file to a physical CD or DVD disc using a process that extracts all the individual folders and files out of the ISO file and places them on the physical media. Windows 7 comes with the built-in Windows Disc Image Burner (not in earlier versions of Windows). Place a blank CD or DVD in your optical drive and double-click the ISO file. Once the disc is burnt, you can use the files and folders the usual way.
Many PCs also come with third-party software for burning discs. If one of these opens when you double-click an ISO file, choose “Burn disc image” or similar command.
There are also free programs for burning CDs or DVDs.
Mounting an ISO file to emulate a disc
Often it is not necessary to actually burn a physical disc. It is becoming more common to use ISO files directly. Some older programs will only recognize an external disc and if that is the case you can mount the ISO file so that it appears to be on a separate drive.
Reading the contents of an ISO file without unpacking it
Some applications can read an ISO file as if it were a disc. For example, virtual machines can install Windows operating systems straight from the ISO without unpacking it. It is also possible to read contents of an ISO file with the archive program 7-Zip. It’s analogous to reading the contents of a ZIP file.
Unpacking an ISO file directly to the hard drive or USB drive
It is also possible to use 7-Zip to extract all the files and folders from an ISO file and place them in a folder on the hard drive or on a USB drive. Just use 7-Zip in the same way as with regular archive files. There are also programs like IsoBuster.
And there you have it – ISO files don't have to be a mystery any longer.