Caching method and data storage system capable of prolonging service lifetime of a cache memory

摘要

In a caching method implemented by a data storage system, a data word as user data is encoded into a codeword that is then written into an area of a cache memory. The codeword includes a data portion, a checksum parity portion and an error correction code (ECC) parity portion. In response to a read request for the user data, the codeword read from the cache memory is decoded based on the ECC parity portion to correct one or more bit errors within the data portion so as to generate a read data portion and a read checksum parity portion. Upon identifying that a validating checksum portion generated based on the read data portion matches the read checksum parity portion, the read data portion serving as the user data is outputted. Otherwise, a data storage unit outputs the user data previously stored therein.