| 摘要 |
PURPOSE:To reduce the chance of occurrence of a bad sector by measuring coincident numbers between plural address data items read out of 10 fields and target address data items, and making the data read operation start when the measured value meets a certain fixed condition. CONSTITUTION:At address section 14 in 10 fields 1 plural same address data items 14A-14C are written previously. A sector number in address data item 14A is compared with a target sector number which is the content of a sector register 34C by a comparator 35, and when they coincide with each other, as a result of comparison a coincident signal is supplied to a counter 38C via a multiplexer 37 and measured. Likewise, when the measured value greater than a predetermined value (m) is obtained from one output side of each counter 38A-38C, the resulted signal S3 is obtained from an AND gate 40. This signal S3 is used as the signal that indicates read of each data of a data field 2. |
