An ISO file is just a disk image.
There are three ways to deal with a disk image:
- Put it on a disk.
- Make it look like you put it on a disk.
- Pretend it’s something else.
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ISOs are a type of archive
The easiest way to think of an ISO file is more like a .zip or .cab archive 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. If interpreted correctly, that raw data may naturally represent files, folders, and formatting details. But, like a disk, the operating system has to look, see what format was used (things like FAT32, NTFS, and the like), and then 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 disc
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 image to an actual disc. It requires a special technique to properly create the image, which is why you need to use tools like ImgBurn. You can’t just copy the file to the media and expect it to work. If you burn the ISO to the disc and still see the .iso file when you look at the disc, then you’ve burned it to the disk as a file – it needs to be burned to the disc as an ISO.
When you examine the properly completed disc, you’ll see all the files and folders that were contained within the ISO image. In the case of the Linux distribution, you’ll probably even be able to boot from the CD or DVD that you just created.
Even when you’re not dealing with software distribution, simply burning the ISO file to a disc will make the contents of the ISO readable by simply reading the contents of that disc.
Treat the ISO file as if it were a disk
There are several utilities out there that will treat an ISO file as if it were a disk drive, although often only for reading.
One product that I’ve used in the past is Daemon Tools. Using this utility, you can “mount” the ISO file and it appears as an additional disk drive on your machine – for example drive M:. Assuming the disk image uses a supported file system (CDFS, NTFS, or FAT32 typically), you can simply read the contents of the ISO directly from the virtual drive.
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 that 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.
Making ISO files
Creating ISO files of CDs or other disks that you own is a convenient way to backup, archive, or (if legal) share them. And it’s actually quite easy to do. There are two approaches:
Create an ISO file from an actual disk. Most CD/DVD burning software includes the ability to “rip” or create an ISO image from a CD or DVD disc. In particular, ImgBurn 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.
Create an ISO file from a collection of files. 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 actually burning to disk.
If you’re simply trying to get at something that’s stored inside an ISO file, go grab a copy of 7-zip which will let you extract the contents just as if it were a .zip file.