What are iso files, and how do I open them?

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Summary: Iso files are a common disk image distribution format. We'll look at the best ways to open iso files as well as a couple of ways to create them.

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An "iso" file is just a disk image.

There are two ways to deal with a disk image: put it on a disk, or make it look like you put it on a disk.

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The easiest way to think of an iso file is more like a "zip" or "cab" file, only without the compression.

An iso file contains the image of a disk. That means it contains all the files and folders that were on that disk, much like a zip or cab file contains a collection of files and folders. The real difference is that an iso is a byte-for-byte copy of the low-level data actually stored on a disk.

There's nothing about the iso format that actually knows about files, folders or formats. It's just the raw data from the disk. Now, naturally that raw data, if interpreted correctly, may know about files, folders and format. But, like a disk, the operating system has to look, see what format was used (things like FAT32, NTFS and the like), and interpret the contents of the iso file as if it were reading the raw data from an actual disk.

There are a few ways to deal with iso files.

Burn the iso file to a disk.

Iso files are frequently used to distribute CD or DVD images. For example if you download a popular Linux distribution what you'll most likely download is actually an iso file. Using a CD or DVD burning program like ImgBurn you can then write that iso disk image to an actual disk. When you examine the completed disk you'll see all the files and folders that were contained in the image. In the case of the Linux distribution, you'll probably even be able to boot from the CD you just created.

Mount the iso file as if it were a disk.

There are several utilities out there that will mount an iso file as if it were a disk drive, though often only for reading. I've not used any enough to recommend, or even mention names, so perhaps readers will chime in with utilities that they've used.

Treat the iso file as if it were an archive.

Recall how I indicated that iso files are much like zip or cab files? As it turns out, some of the popular archiving utilities, including WinRAR and my personal favorite 7 Zip can also read and extract the contents of iso files.

All you need to do is use those tools' view or extraction functions on the iso file to examine its contents or extract some or all of the files you need.

Creating iso files

Creating iso files of CDs or other disks you own is a convenient way to backup, archive or (if legal) share them. And it's actually quite easy to do.

Most CD/DVD burning software includes the ability to rip or create an iso image. ImgBurn, in particular, is perhaps one of the easiest tools to use for this purpose. Just insert your CD, tell ImgBurn where to place and what to name the iso file, and push a button.

ImgBurn can also be used to create an iso image from files you specify, much as if you were actually burning files to CD or DVD. After collecting the files that you want to place in the image, you can instruct ImgBurn to create an iso file instead of burning to disk.

Related:

• How do I burn something to CD? Burning files to CD is a great way to back up or to easily transfer files elsewhere. There are several burning options including Windows itself.

• Audio CDs - what format should I use to burn my Audio CDs? Audio CDs are different from data CDs. Typically your burning software needs to know how to create audio CDs, and you need to explicitly tell it to do so.

Article C3228 - December 5, 2007