A file with the extension .dmg which uses a proprietary disk image format commonly found on Mac OS X.
DMG stands for disk image. It is a format commonly used to distribute files and applications among Apple computers. A DMG file is like a virtual DVD or hard drive. DMG files can be “mounted” on your Mac to work with their contents. They can even be burned into an actual physical disk.
Fig. 1 – A disk image mounted as a virtual drive.
In order to understand the concept of a DMG disk image, think of a storage volume such as a CD, DVD, hard drive, or external hard drive. A DMG file is like one of these devices in that it serves as a means to encapsulate documents, images, software, and other files. The difference between a DMG file and those mentioned above is that with a DMG, there is no physical storage medium.
Once you are done working with the contents of a DMG file, you will want to remove or “unmount” it from your system. Do this by opening the Finder and clicking the eject icon shown next to the virtual drive’s icon. You can also do this by going to your desktop, clicking once on it’s icon, and pressing CMD+E.
DMG file represents disk image format commonly found on Mac OSX. This format allows secure password protection as well as file compression and hence serves both security and file distribution functions. Its most common function is the distribution of software over the Internet. When opened, DMG files are "mounted" as a drive within the Finder.
DMG files are Mac-specific and are not intended for use in Windows; however, Windows Daemon Tools may be able to mount virtual drives from some DMG image files; other utilities may also be able to convert DMG files to a format that can be recognized by Windows.
Open DMG file on Mac OS
Open DMG file on Windows
PowerISO is a powerful CD/DVD image file processing tool, which allows you to open, extract, create, edit, compress, encrypt, split and convert ISO files, and mount these files with internal virtual drive. It can process almost all CD-ROM image files, including ISO, BIN, DAA, UIF, and DMG files. If you have PowerISO, you will own ISO extractor, ISO converter, ISO burner, ISO creator and virtual drive.
On Windows PC, you can use PowerISO to process the DMG files. With PowerISO, you can:
- Extract the files and folders in dmg files
- Burn the dmg file to a CD or DVD disk
- Convert dmg file to standard ISO file.
Please do the following steps.
Click menu "File" | "Open"
Choose DMG file and click Ok.
- Click to extract files and folder from DMG files.
Most .dmg files are compressed and must be expanded before burning to CD/DVD. The expansion process is popularly called "convert to ISO." Acturally, you can convert DMG file to ISO image with the help of MagicISO. The following instructions will show you the process of conversion.
Download MagicISO and install it on your computer. Then, run MagicISO.
Click to open DMG files.
Click to open Properties Dialogue.
Uncheck Apple HFS and Apple HFS+.
Check ISO 9660, Joliet, and UDF.
Click to save as to ISO image, or click to burn to CD/DVD without saving.
Most .dmg files are compressed and must be expanded before burning to CD/DVD. The expansion process is popularly called "convert to ISO" on the web (due to a program called dmg2iso), but that is not technically correct. ISO (or ISO 9660) is an older file system format used on CDs. Actually converting a dmg to an ISO 9660 image would not make sense since it would remove all of the Mac specific data. Burning dmg files is a two step process - 1)Expand the dmg and 2)Burn the expanded dmg (as an image not a file). Some burning programs may require renaming the dmg with a .iso extension before it will be recognized.
Burn a DMG file to CD/DVD with TransMac
Download and install TransMac on your PC. Run it.
Select Open Disk Image from the File menu.
Right-click the dmg in the left treeview pane and select Expand. Make sure you have room for the expanded image on your disk drive since it will be larger than the original.
After expanding, TransMac asks to open the expanded ISO dmg. Select Yes.
Right-click the expanded dmg and select Burn to CD/DVD. Select the CD/DVD drive and click OK.
One way to store or group files on a Mac is to create a Disk Image. A Disk Image is a file which has the properties of a separate hard drive or CD. It has a size limit and options for encryption to keep your files safe and secure. This how-to will work with Mac OS X.
Create a New Folder and place the files you would like in your disk image into this new folder.
Right click (or CTRL-Click) the folder and select "Get Info" and note the size of its contents.
Open Disk Utility (Applications > Utilities > Disk Utility)
Click the "New Image" icon to create a new disk image. Enter a name for the Image, and select a size adequate for the size of your folder you created in Step 2. Set the encryption to "none" and Format to "read/write disk image." or "DVD/CD Master." See Tips to learn how to encrypt the image.
Place the contents of the folder from Step 2 into the newly mounted disk image.
Unmount the Disk Image by dragging its icon to the Trash. In the Finder window, you can also click the Eject symbol next to the mounted image.
You can encrypt your Disk Image with a password if you would like your files to be private. Simply Select "AES-128" under the "Encryption" drop-down menu. After you click "Create" and it will ask you to create a password for your files. If you add the password to your key chain, you will not have to enter your password to access the .dmg file when logged into your account.
After you add your files to the image, you can unmount it and then click the "Convert" button in the toolbar. This will let you compress the image or change it to read only (or add encryption).
When you double click a .dmg file, it will "Mount" on the desktop. This is the only way to access or modify the contents of the Image.
A .dmg file can be a very easy way to send files from one Mac to another. Any Mac can mount and access the Disk Image on their computer.
To create an image from a folder, drag the folder onto the Disk Utility-icon, or choose "New->Disk image" from folder in the File-menu in Disk Utility.