Disk Image

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Disc.png Disk Image Types

International
› .ISO

Macintosh
› .DMG
› .CDR

Windows
› .GHO
› .GHS

A disk image is a file containing not only files and folders but also metadata information, such as filesystem stucture and boot commands. Uses include creating a digital backup of optical media (CD/DVD) or transferring software over the internet.

Creating a Disk Image

Macintosh

1. Insert the optical media (CD/DVD) into the drive.
2. In the menubar at the top, select Go, then Utilities. Open Disk Utility.
3. Go to File, New, then New Disk Image From ... and select your optical media.
4. Follow the instructions and save a "Master" file. This can be renamed to a .iso image.

Windows

Windows does not natively create ISO images. For this reason we recommend IMGBurn for creating ISO images.

With Windows 7, you can burn an ISO using Windows Disc Image Burner. Instructions are located here. However, IMGBurn is still recommended.

Linux

1. Insert the optical media into the drive. Unmount the media.
2. Use the following command, dd if=/dev/cdrom of=/home/me/myimage.iso

 of - output file
 if - input file

Burning a Disk Image

Macintosh

1. Insert blank optical media (CD/DVD) into the drive.
2. In the menubar at the top, select Go, then Utilities. Open Disk Utility.
3. Drag the disk image into the left pane and then highlight it. Click the burn button.

Windows

These Instructions will all be based around how to use IMGBurn to create an ISO image. 1. Download
IMGBurn for Windows. (Vista/7/8)and install the program.

2. Put a blank disc in your CD/DVD drive, and right click on the ISO file you wish to burn onto the CD. One of the selections in the drop down should be "Burn using ImgBurn. This one will open up the program.

3. ImgBurn will open up with the source (the ISO file you clicked on) and the destination (CD/DVD in your drive) already filled in. You can leave all the default settings that are on the screen. At the bottom of the screen there is a Write button. This button looks like a piece of paper with a CD on it, with an arrow pointing to a CD.

4. The program will take care of burning the CD, and once it is done, a popup will tell you "Operation Successfully Completed". At that point it is safe to close ImgBurn and remove the disk from your drive.

Note. Closing ImgBurn or removing the disk from the drive before the process is finished will result in an incomplete and unusable image being burned to the drive.

Linux

1. Insert blank optical media (CD/DVD) into the drive.
2. Run, cdrecord -scanbus to determine the drive (i.e. 0,0,0) to burn to.
3. Run the following command, cdrecord -v -pad speed=8 dev=0,0,0 myimage.iso

Using a Disk Image

Macintosh

1. Double-click the .iso file. It will mount on the desktop.
2. To eject, right-click the desktop mount and select, "Eject".

Windows 8

Double-click the .iso file and it will open up in file explorer as a CD/DVD.

Windows 7 & below

Windows 7 & below does not natively support editing ISO images.

Linux

1. Run the following command, mount -t iso9660 -o loop myimage.iso /mnt/
2. To eject, run the following command, umount myimage.iso

Encrypted Disk Image

An encrypted disk image (.DMG) is a 128-bit or 256-bit encrypted file that, when opened, will prompt the user for a password. Once authenticated, the disk image will mount on the desktop allowing the user to copy data to or from the mounted disk image before unmounting the image to secure it. For more information, please see OS X Encrypted Disk Image.


Related Links:

Mac OS X Encrypted Disk Image

Wikipedia - Disk Image

Wikipedia - ISO Image