How to Turn a Disc Into DMG

DMG files are often used in place of CDs, when applications are downloaded directly from the developer.

Apple's DMG format is similar to an ISO file, it simulates an image of a physical disc, storing data in a single package while maintaining the internal file structure. It's commonly used for installing software, and while most larger, more complex applications will include an installer application that distributes files to the appropriate locations and libraries automatically, many smaller applications use a single DMG file in place of an installer. Mac OSX includes tools for creating your own DMG files.

Things You'll Need

• Macintosh computer running OSX

Instructions

1. Power on the machine and boot into OSX. Click the "File" menu on the top toolbar and select "New Finder Window." In the new window, click the "Applications" shortcut on the left, and scroll down to the "Utilities" folder. Inside the folder, double-click on "Disk Utility."

2. Allow the "Disk Utility" application to load, and insert the disc you plan to convert into a DMG file. The drive will read the disc for several moments to determine the file structure. When this completes, the disc will appear in the list of drives in the left-hand toolbar.

3. Click the disc icon to highlight it, then click the "New Image" button on the top toolbar of the "Disk Utility" application. A dialog box will appear requesting you choose a save location for the DMG file. Navigate to an appropriate location and type a file name in the top field of the dialog box, ensuring you leave the ".dmg" extension at the end. When finished, click "Save." A DMG file containing the contents of the disc will be created in the specified location.

Tips & Warnings

• A shortcut to the Disk Utility application can be implemented if you often rip discs to DMG files. Insert the disc at the desktop screen and dialog will open asking which application you wish to use to open the data on the disc. Click the drop-down box and select "Disk Utility." The dialog box contains a "Always Do This" check-box that can further streamline the process.

References

• Michael Grace; Create .DMG image from a disk
• Apple; Creating a Disk Image