Is there a difference in the disc layout of a recordable MD and pre-recorded MD?
On recordable MDs, 32 out of 36 sectors in every cluster (the smallest recordable unit) are used for storing audio data. Of the remaining 4 sectors, 3 are needed to accommodate the start up and run out of the error correction code, as stated in the Minidisc IEEE paper: “Because of the long interleaved ACIRC error correction code, three sectors must be used as “linking sectors.” If the user changes or adds new data to the MD disc, two or three sectors for every start and end position of the new data need to be recorded.”. In other words, some space is wasted to accommodate re-recordability. On pre-recorded MDs, however, the data is fixed during mastering as one continuous stream, so these 3 extra sectors can be devoted to sub-data (but there is no documentation as to what this extra sub-data space could be used for). The Sony DADC MD handbook says that the maximum duration of a pre-recorded MD is 78:16.
