code: public void initBackingIndexNew(IOResourceProvider file) {
  		if (idx != null) {
  			throw new IllegalStateException();
  		}
  		//8 byte page, 1 byte flag 
  		idx = new PagedUniqueLongLong(PAGE_TYPE.FREE_INDEX, file, 4, 8);
  		iter = idx.iterator(1, Long.MAX_VALUE);
  	}
docs: Constructor for creating new index.
  @param file The file