| 摘要 |
PURPOSE:To recognize visually marked data, to discriminate programs recorded on a disk, to obtain address data at a part except a marked signal recording part in a readout section and to attain a conventional random access by recording the marked data in the prescribed angular range of the readout section. CONSTITUTION:Marked signals as shown in a period T1 are recorded in a part 8b1 accounting for an approximately half-periphery of a readout section 8b on a disk 8. Bit shapes are different in a recording part of the marked signal ''1'' and that of ''0'', and light reflectances are also different. With the aid of groups of dots having different light reflectances each character and figure comprising marked data such as the disk number can be recognized visually. In a remaining half-periphery part 8b2 of the readout section 8b recording signals at least marked by address bits Adr as shown in a period T2 are recorded. |
