A first and second stroller portions are described to form a modular stroller. They also provide improved decoding speed through a fast path design wherein decoding of a most probable symbol requires few computational steps. These are heated so as to volatilize the volatile organic medium, and a pressure is applied to the conductive pattern member in its thickness direction. Thus, it is possible to reduce a noise that is caused from disk rotation if the size of data to be recorded is small or when a noise is felt relatively big.