File type: Mac OS X Disk Image
The usage of the DMG file extension is in the context of a mountable disk image file which is generated by the Mac OS X Operating System platform. Once the file is opened, the system will mount it in a virtual disk located on the user's desktop.
This type of file is normally utilized for the distribution of software installation packages for the Macintosh computer system.
Prior to the introduction of this file format, the Mac environment utilized the IMG up until the introduction of the Mac OS 9. The Apple Disk Utility is the main application associated by users to this particular file type under the Macintosh platform and is bundled with the Mac OS X installation package.
Although not meant to be directly opened under the Microsoft Windows Operating System platform, the DMG format file can be accessed by Windows users by using some third party applications in the market. Basically, the DMG file extension can be compared to the EXE or ISO format of Windows and can even function as a complete virtual drive for the system.
The mimicking of physical CD drives is a workaround implemented by the system to address problems that may arise from CD requirements of some software programs including support for the efficient usage of an organization's resources.