anchor.diff:            echo "creating VirtualBox pass-through disk wrapper (no copying involved)..."
             VBoxManage internalcommands createrawvmdk -filename disk.vmdk -rawdisk $diskImage
   
  +          ${optionalString (cfg.extraDisk != null) ''
  +            echo "creating extra disk: data-disk.raw"
  +            dataDiskImage=data-disk.raw
  +            truncate -s ${toString cfg.extraDisk.size}M $dataDiskImage
  +
  +            parted --script $dataDiskImage -- \
  +              mklabel msdos \
  +              mkpart primary ext4 1MiB -1
  +            eval $(partx $dataDiskImage -o START,SECTORS --nr 1 --pairs)
  +            mkfs.ext4 -F -L ${cfg.extraDisk.label} $dataDiskImage -E offset=$(sectorsToBytes $START) $(sectorsToKilobytes $SECTORS)K
  +            echo "creating extra disk: data-disk.vmdk"
  +            VBoxManage internalcommands createrawvmdk -filename data-disk.vmdk -rawdisk $dataDiskImage
  +          ''}
  +
             echo "creating VirtualBox VM..."
             vmName="${cfg.vmName}";
             VBoxManage createvm --name "$vmName" --register \
  
positive.code:           Run <literal>VBoxManage modifyvm --help</literal> to see more options.
          '';
       };
      };
    };
  
  
negative.code:         '';
      };
  
      fileSystems = {
        "/" = {
          device = "/dev/disk/by-label/nixos";
          autoResize = true;
          fsType = "ext4";
        };
      } // (lib.optionalAttrs (cfg.extraDisk != null) {
        ${cfg.extraDisk.mountPoint} = {
          device = "/dev/disk/by-label/" + cfg.extraDisk.label;
          autoResize = true;
          fsType = "ext4";
        };
      });
  
      boot.growPartition = true;
      boot.loader.grub.device = "/dev/sda";
  