DVD, DOS Device Driver (.dvd)
The DVD System file format
DVD files are used as drivers for the devices running on MS-DOS. These driver files enable the communication between the computer or other device and the operating system, in this case, MS-DOS. In some instances, the drivers and DVD files are already installed on Windows. Sometimes, however, the drivers have to be installed manually. This can often be done using a disc or other medium that comes with the purchase of the device. Many vendors also provide driver downloads for their devices on their website.
Technical details of DVD files
Oftentimes, DVD files are confused for video files containing a copy of a movie on a disc. While the medium is called a DVD, the movie files are usually saved as VOB files.