Memory system

A memory system accessible from a host, the memory system comprising:

• a nonvolatile memory,
• a memory controller included in a first package, and
• a memory interface circuit included in a second package, the second package being different from the first package, wherein:
• the memory controller includes an encoder for performing encoding for error correction, and is configured to:
• encode first data into second data using the encoder, and
• program the second data into a first location in the nonvolatile memory;
• the memory interface circuit is interposed between the nonvolatile memory and the memory controller, includes a decoder for performing decoding for error correction, and is configured to:
• read the second data, as third data, from the first location in the nonvolatile memory,
• diagnose the third data by decoding the third data using the decoder, and
• convey a result of the diagnosis to the memory controller,
• the memory controller is further configured to determine, on the basis of the conveyed result of the diagnosis, whether to execute a normal refresh or a reprogramming refresh,
• in a case where the normal refresh is to be executed, the memory controller reads the second data, as fourth data, from the first location in the nonvolatile memory, corrects an error bit included in the fourth data by decoding the fourth data to generate fifth data, and programs the fifth data in a second location in the nonvolatile memory, the second location being different from the first location,
• in a case where the reprogramming refresh is to be executed, the memory controller issues a reprogramming refresh instruction to the memory interface circuit;
• and
• the memory interface circuit is further configured to:
• in response to the reprogramming refresh instruction,
• read the second data, as sixth data, from the first location in the nonvolatile memory,
• correct an error bit included in the sixth data by decoding the sixth data using the decoder to generate seventh data, and
• reprogram, without erasing, the seventh data in the first location in the nonvolatile memory.