Digital tape recorders

There is disclosed an apparatus and method capable of reducing the size of a cylinder for use in a digital audio tape recorder (R-DAT) system and miniaturizing the R-DAT system by using a drum 24 with a small diameter, by which a portable, compact R-DAT system can be realized easily and employing time expansion on recording and compression on playback. The head-drum 24 of the R-DAT system includes: an upper drum 22 whose a first head 20 and second head 21 for recording and playing audio information are symmetrically attached in a direction of a core thereof at the lower side of the cylinder surface in which the diameter of the cylinder is smaller than that of a standard cylinder by a given factor; the entire drum 24 including the upper drum 22 and a lower drum 23, said lower drum having a cylinder of the same diameter with that of the upper drum and supporting said upper drum; and a small-sized motor 25 for rotating said entire drum 24.