code: @Override
  	protected void writeDataBlock(byte[] data, int offset, int len, int blockHandle) throws DataStoreException
      {
      	try
          {
  	        dataRandomAccessFile.seek((long)blockHandle*blockSize);
  	        dataRandomAccessFile.write(data,offset,len);
          }
      	catch (IOException e)
      	{
      		throw new DataStoreException("Cannot write data block "+blockHandle+" : "+dataFile.getAbsolutePath(),e);
      	}
      }
docs: /*
  (non-Javadoc)
  @see net.timewalker.ffmq4.storage.data.impl.AbstractBlockBasedDataStore#writeDataBlock(byte[], int, int, int)