Fujitsu Corporation

Kana Ono

Michael James

An error correction device, an error correction program and an error correction method can reduce the processing time necessary for the process of correcting errors that involve erasure in a reception word by using a software and hardware properly and effectively. As an error-correcting circuit for correcting errors that do not involve erasure receives a reception word that involves erasure from an RDC, an erasure information holding section holds the erasure information and a syndrome generating section generates a syndrome from the reception word so that a erasure judging section transmits the erasure information and the syndrome to an MPU. In the MPU, an erasure error value computing section and erasure correcting section correct only erasure and store the reception word that does not involve erasure in an RAM. The reception word from the RAM is input again to the error-correcting circuit for correcting errors that do not involve erasure by way of a data bus and a switch. The erasure judging section judges the reception word as one that does not involve erasure and has Chien search section and an error-correcting section correct errors.

Error correction device, error correction program and error correction method

When data is read from a disk and stored in volatile memory, check bits are generated and stored in the memory using an algorithm such as cyclical redundancy check (CRC). The CRC algorithm operates on the basis of the bit length in which the data is organized, such as 8 bits. If the data has errors, an error correction code (ECC) algorithm is used to correct the data errors, but the ECC algorithm operates on the basis of symbols having a different bit length, such as 10 bits. To avoid having to re-read the data from the volatile memory to adjust the CRC value, the CRC algorithm is executed on selected mask data developed by the ECC algorithm, the CRC algorithm being executed on the basis of the second bit length to generate a CRC mask. The CRC mask corrects the stored CRC value.

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Kana Ono