from another standpoint that the sate of a given block being deleted or not is controlled or supervised by the flag area flag of that given block and additionally by the flag areas of the two succeeding blocks as will be seen in fig5 in other words every block is controlled or managed at three discrete areas or locations as to whether it is logically deleted or not in this way redundancy can be imparted to the information indicative of the deleted or non deleted state of any given block fig6 shows a general arrangement of an optical disc storage system which allows access to be made to the recording medium of the structure described above referring to fig6 a reference numeral 11 denotes an interface controller for controlling data transmission to or reception from a host or high rank system cpu channel a numeral 12 denotes a microprocessor for operating the individual components of the the optical disc control system through predetermined procedures in accordance with commands issued by the host or high rank system a numeral 13 denotes a memory for storing therein microcommands for commanding the control operations performed by the microprocessor 12 numeral 14 denotes a buffer memory having a capacity which corresponds at least to the amount of data of one track of the optical disc a numeral 15 denotes a write circuit for modulating or coding the data outputted from the buffer memory 14 and subsequently supplying the modulated or coded data to an optical head circuit 10 and a numeral 16 denotes a read circuit for demodulating or decoding the output signal s10 from the optical head circuit 10.