Disk imaging refers to copying the contents of a data storage device or medium and transferring this to another similar medium or device. In its original context, disk imaging implies the creation of an exact duplicate of a computer's hard disk drive - including its programs, setup, and data stored in a particular, compressed file format.

Disk imaging aims to provide the user with a replication of a computer's systems and data - needed in case of a catastrophic disk crash where the user needs to recover systems or data (e.g., in the event of a virus attack or accident), to 'clone' a system's set-up for installation in another computer or to move these to another hard drive.

The Uses of Disk Imaging

Disk images are used to copy optical media, including DVDs, Blu-ray Discs, and more. It is also used to make full clones of hard drives. As mentioned above, disk images are often used as backup files. However, it is also related to the virtual disk.

A virtual disk can emulate any type of physical drive, such as a hard drive, tape drive, key drive, floppy drive, CD/DVD/BD/HD DVD, or network share, etc.; of course, since it's not physical, it needs to match virtual reader device. Emulated drives are usually created in RAM (called a RAM disk), or hard drive for fast read/write access. Typical uses for virtual drives include mounting disk images of CDs and DVDs and mounting virtual hard disks for On-the-Fly Encryption ("OTFE").

Virtual drives are usually read-only and are used to mount existing disk images that the drive cannot modify. However, some software provides virtual CD/DVD drives that can produce new disk images; this type of virtual drive is known by various names, including "virtual recorder".

Disk Image Application

Generally, the two most widely used aspects of disk imaging are system backup and software distribution/deployment. The following is a specific introduction to the advantages of disk imaging in these two aspects:

System Backup:

Some backup programs only back up user files; boot information and files locked by the operating system (such as files in use at the time of the backup) may not be saved on some operating systems. Disk images contain all files, faithfully replicating all data, including file attributes and file fragmentation status. For this reason, it can be used to back up the operating system and enable accurate and efficient one-time system image recovery after modifications to the system or virtual machine.

Software Distribution/Deployment:

When you are in charge of the IT department of a small-to-medium size company, you can use the disk image to distribute software across a company network or for portability. When distributing software via disk images, you can download and install the software on a large number of networked machines with little or no disruption to users. Some tasks can even be scheduled to be updated only at night so that machines are not disturbed during working hours.

How to Create a Disk Image

The primary use of disk imaging software is to provide quick and easy back-ups of computer software and data stored on hard disks. While most people think of backing up data, disk imaging programs back up data and the computer's systems and configuration.

In effect, a disk imaging program captures an 'image' of an active computer system - its structure, registry programs, 'tweaks', software, etc. This is especially useful in case of problems encountered during the life of the system - malicious virus attacks that may erase systems or data, software or hardware glitches that may require formatting or wiping the hard disk, and catastrophic incidents like man-made disasters or accidents (e.g., fire, floods, and the like).

In other words, a disk image means having an updated 'rescue disk' that one uses to quickly reinstall the system to what it was at the time of 'duplication,' without having to go through the involved process of installing software and resetting or tweaking settings once again to the desired configuration.

A second application for disk imaging software is for systems administrators who oversee multiple computers with similar configurations. Rather than spending time transferring and configuring systems on different computers, disk imaging software makes the task easy and quick - duplicate the systems on one machine and install the 'disk image' on another computer.

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[Data Protection] The Differences between System Image and Full Backup

System Image backups all the essential components of the operating system, while full backup allows users to back up data selectively. Both system image and full backup have their advantages and disadvantages. However, if you need to safeguard your system and avoid installing Windows again, you must opt for a system image.

system image vs full backup

Disk Image Software

The most popular disk imaging software is Symantec Ghost. The initial versions of Ghost were used to duplicate or clone entire disks (without regard to whether the disk was half-empty or not), but later versions were configured to provide the user with a choice of copying entire disks or individual partitions. Ghost also provides for multiple means of duplicating systems or data; one can copy these to a second disk on the same machine; duplicate these to another computer linked via a network or parallel cable, or copy the image to a network or tape drive.

A corporate edition of Ghost allows for multicasting, or the simultaneous transfer of images from one computer to several ones - an approach that reduces the stress on a computer network that has to transfer large files (usually several hundred megabytes or more).

Best Disk Image Software - EaseUS Todo Backup

EaseUS Todo Backup is a reliable disk image software. It is the safe backup & recovery software offering backup, disk clone, and disaster recovery solutions, supporting a one-click system, files, and applications backup.

  Free Download

Support Windows 11/10/8/7

Step 1. Launch EaseUS Todo Backup on your computer, and click Create Backup on the home screen and then hit the big question mark to select backup contents.

backup outlook mail step1

Step 2. To back up your Windows operating system, click "OS" to begin the backup task.

backup outlook mail step2

Step 3. Your Windows operating system information and all system related files and partitions will be automatically selected so you don't need to do any manual selection at this step. Next, you'll need to choose a location to save the system image backup by clicking the illustrated area.

system backup

Step 4. The backup location can be another local drive on your computer, an external hard drive, network, cloud or NAS. Generally, we recommend you use an external physical drive or cloud to preserve the system backup files. 

backup outlook mail step4

Step 5. Customiztion settings like enabling an automatic backup schedule in daily, weekly, monthly, or upon an event, and making a differential and incremental backup are available in the Options button if you're interested. Click "Backup Now", and the Windows system backup process will begin. The completed backup task will display on the left side in a card style.

backup outlook mail step 5

Formats of Disk Images

All operating systems support creating and running disk images, so these disk images have different formats. For example, the disk image file suffix created by EaseUS Todo Backup is .pbd. Here we will list several common disk image formats:

  • Apple Disk Image (.dmg)
  • IMG (file format)
  • VHD (file format)
  • VDI (file format)
  • VMDK
  • QCOW

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Updated by Daisy

Daisy is the Senior editor of the writing team for EaseUS. She has been working in EaseUS for over ten years, starting from a technical writer to a team leader of the content group. As a professional author for over 10 years, she writes a lot to help people overcome their tech troubles.

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Written by Larissa

Larissa has rich experience in writing technical articles. After joining EaseUS, she frantically learned about data recovery, disk partitioning, data backup, and other related knowledge. Now she is able to master the relevant content proficiently and write effective step-by-step guides on computer issues.

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