code: @Override
  	protected void writeFirstBlock() throws DataStoreException
      {
      	try
      	{
  	    	allocationTableRandomAccessFile.seek(AT_HEADER_FIRSTBLOCK_OFFSET);
  	        allocationTableRandomAccessFile.writeInt(firstBlock);
      	}
      	catch (IOException e)
      	{
      		throw new DataStoreException("Cannot write to allocation table file : "+allocationTableFile.getAbsolutePath(),e);
      	}
      }
docs: /*
  (non-Javadoc)
  @see net.timewalker.ffmq4.storage.data.impl.AbstractBlockBasedDataStore#writeFirstBlock()