| 摘要 |
PURPOSE:To prevent a recoverable data error from advancing to an unrecoverable error by verifying a read error rate each time a reading instruc tion is finished. CONSTITUTION:A read error rate calculation part 19 always monitors an interruption signal 44 to be sent from a retry control part part 17 each time the reading instruction is finished. When the signal 44 is inputted, a cumulative input data length is extracted from an input instruction data length storage part 9, the cumulative number of times of retry is extracted from a retry time number storage part 14, the read error rate is calculated from both of numbers, and it is decided whether this read error rate exceeds a threshold value or not. When it exceeds the threshold value, a threshold value exceed signal 45 is sent to a message output part 20. The output part 20 always monitors whether the signal 45 is inputted from the calculation part 19 or not and when the signal 45 is inputted, a read error rate threshold value exceed message is prepared and displayed on a display device 3. Thus, each time the reading instruction is executed, the read error rate is verified. |
