anchor.diff:            VBoxManage internalcommands createrawvmdk -filename disk.vmdk -rawdisk $diskImage
   
             echo "creating VirtualBox VM..."
  -          vmName="NixOS ${config.system.nixos.label} (${pkgs.stdenv.system})"
  +          vmName="${cfg.vmName}";
             VBoxManage createvm --name "$vmName" --register \
               --ostype ${if pkgs.stdenv.system == "x86_64-linux" then "Linux26_64" else "Linux26"}
             VBoxManage modifyvm "$vmName" \
  -            --memory 1536 --acpi on --vram 32 \
  +            --memory ${toString cfg.memorySize} --acpi on --vram 32 \
               ${optionalString (pkgs.stdenv.system == "i686-linux") "--pae on"} \
               --nictype1 virtio --nic1 nat \
               --audiocontroller ac97 --audio alsa \
  
positive.code:           The size of the VirtualBox base image in MiB.
          '';
        };
      };
    };
  
    config = {
      system.build.virtualBoxOVA = import ../../lib/make-disk-image.nix {
        name = "nixos-ova-${config.system.nixos.label}-${pkgs.stdenv.system}";
  
        inherit pkgs lib config;
        partitionTableType = "legacy";
  
negative.code: 
            echo "exporting VirtualBox VM..."
            mkdir -p $out
            fn="$out/${cfg.vmFileName}"
            VBoxManage export "$vmName" --output "$fn"
  
            rm -v $diskImage
  