Howto open and burn .mdf files (with Nero)
Files with the extension .mdf and .mds are iso files and are made with the program Alcohol 120%. These files are like .bin en .cue files. Mdf/mds files are an exact data copy i.e. a cd- or dvd-rom. For backup purposes making mdf files are a good way to make an usable copy of the cd- and dvd-rom. A nice side effect of mdf files, is the possibility of playing the file in a cd/dvd-rom emulator program.
Mdf capable applications
Alcohol 120% is a commercial program Alcohol 120% which not only can read mdf files, it can make them too. Also the free virtual cd-rom/dvd-rom emulator Daemon tools can read the contents of the mdf files and it can also play the file like a cd- or dvd-rom.
Nero burning rom is also capable of burning .mdf files
Mdf files cannot directly be burned by Nero. To do this you just change the extension .mdf to .iso. From the Nero menu go to the item burner or recorder and select the option burn image. From there you can select the .iso file. After that it's just hit the burn button and relax, Nero will burn the file.
I have also made a MDF to ISO convertor which can be downloaded here. This program does the renaming for you and starts Nero or other burn program to burn the file.