FAST CACHE WITH INTELLIGENT COPYBACK

Method and apparatus for intelligent caching, protection and transfers of data between a cache and a main memory in a data storage environment, such as but not limited to a solid-state drive (SSD). A main memory (MM) has non-volatile memory (NVM) cells configured for persistent storage of user data. A fast response cache (FRC) has NVM cells configured to provide storage of first data prior to transfer to the MM. A write cache (WC) has NVM cells configured to provide storage of second data prior to transfer to the MM. A controller directs input data to either the FRC or the WC. A first type of error correction encoding (ECC1) is applied to the first data and a different, second type of error correction encoding (ECC2) is applied to the second data. Data may be sent from the FRC to the MM either directly or through the WC.