anchor.diff:                tar xjf /install/nixos.tar.bz2 -C /etc/nixos/nixos
                 mkdir -p /etc/nixos/nixpkgs
                 tar xjf /install/nixpkgs.tar.bz2 -C /etc/nixos/nixpkgs
  -              mkdir -p /etc/nixos/services
  -              tar xjf /install/services.tar.bz2 -C /etc/nixos/services
                 chown -R root.root /etc/nixos
               end script
             ";
  
positive.code:       { source = nixpkgsTarball + "/nixpkgs.tar.bz2";
          target = "/install/nixpkgs.tar.bz2";
        }
        { source = servicesTarball + "/services.tar.bz2";
          target = "/install/services.tar.bz2";
        }
      ];
  
      # Closures to be copied to the Nix store on the CD.
  
negative.code:   nixosTarball = makeTarball "nixos.tar.bz2" ../..;
  
  
    # Put Nixpkgs in a tarball.
    nixpkgsTarball = makeTarball "nixpkgs.tar.bz2" nixpkgs;
  
  