Inspection word forming method

PURPOSE: To improve the reliability in digital information data by disposing a parity sector from the digital information data consisting of plural sectors. CONSTITUTION: The sector is constituted of an address mark 1 and the digital information 2 and the digital information data 2 consists of an information word 3 and an inspection word 4 formed from the information word 3. Namely, a parity bit is formed by the information word 3 of the digital information word 2 to have as one information word 3. Thereby, even when one of other sectors constituting the digital information data cannot be read, a recovery operation causes the information word 3 of the sector which cannot be read to be reproduced. COPYRIGHT: (C)1989,JPO&Japio