code: private FatType fatTypeFromDevice() throws IOException {
          final long sizeInMb = device.getSize() / (1024 * 1024);
          
          if (sizeInMb < 5) {
              return FatType.FAT12;
          } else if (sizeInMb < 512) {
              return FatType.FAT16;
          } else {
              return FatType.FAT32;
          }
      }
docs: Determines a usable FAT type from the {@link #device} by looking at the
  {@link BlockDevice#getSize() device size} only.
  
  @return the suggested FAT type
  @throws IOException on error determining the device's size