A device for recording data and data structures on a write-once storage medium. The device has writing means for recording the data and the data structures and controlling means for generating the data structures and controlling the writing means. The data structures comprise space bit map and defect management structures. The controlling means are adapted to record the data structures at a predefined temporary location on the write-once storage medium and to finalize the write-once storage medium by recording the data structures at a predefined fixed location as defined for a rewritable storage medium.