Dvd ram is a rewritable medium that uses phase change technology for recording two generations of dvd ram are available 26gb52gb and 47gb94gb dvd ram is designed for data intensive high performance applications data stored on dvd ram can be accessed in the same manner as a hard drive with drag and drop capabilities and can be overwritten 100 000 times single sided discs are available bare or with a type 4 disc removable cartridge for reading in later generation dvd readers