A disk image serves as an exact copy of a disk. This could be a traditional, optical disc, such as a CD, DVD, or Blu-Ray, or it could be a physical disk drive - like a HDD, solid-state drive, USB flash drive, or tape drive. In any case, the disk image contains the entire structure as well as all of the original files, folders, and properties of the original disk or disc.
Generally speaking, disk images are a great way to backup your important data. Whether you're trying to preserve digital photographs on a personal computer or archiving mission critical data on behalf of a Fortune 500 company, a disk image is a viable solution in most scenarios. However, it's not the only data backup option available.
In fact, disk images are often confused with other data backup methods and, in particular, disk cloning. Although these two data backup methods have many similarities, they are two distinct processes.
Disk Imaging vs. Disk Cloning
While the two terms are often used interchangeably, especially by novice users, disk imaging and disk cloning actually yield two very different results. Disk imaging is typically used to create a digital image of an entire system - including configuration settings and all. Because of this, disk images are often larger than disk clones. To offset this, disk images can utilize granular data recovery - which allows you to select individual files for restoration instead of forcing you into a time-consuming full restoration.
A disk clone, on the other hand, essentially copies the entire contents of a computer's hard drive into a single file. In many case, the single file is an uncompressed disk image. This differs from disk imaging, which produces an uncompressed file - generally an ISO file. However, the exact extension could differ depending on the software you're using to create the image.
Full vs. Differential
Depending on your exact needs, there are two different types of disk imaging options available - full and differential.
Most organizations opt for differential disk imaging, as it saves a considerable amount of time over creating a new image for every backup. However, this ultimately means dedicating a significant portion of your storage space to the image file.
Using Your Disk Image
Disk images are usable in a variety of ways. When using specialized backup software, they can be created and accessed via the software itself. If the disk image was made from a computer's hard drive, it can either be restored to a new drive (to replicate the original drive), or mounted as a virtual drive that works in conjunction with your current system. For images that use a CD, DVD, or Blu-Ray as its source, these can also be burned onto another physical disc.