Memory module and operating method

A memory module comprising:

• a memory device configured to receive a first refresh command from a host, and perform a refresh operation in response to the first refresh command;
• a computing controller configured to detect the first refresh command provided to the memory device from the host, and read a first data stored at a first address of the memory device at a first time point after a preset time elapses from a first refresh time point when the first refresh command is detected;
• a buffer in which the read first data is stored;
• and
• error pattern storage in which a plurality of error patterns are stored,
• wherein the computing controller is configured to read the first data stored at the first address of the memory device, and then write a first error pattern from among the plurality of error patterns at the first address.

A method for operating a memory module, the method comprising:

• refreshing a memory device in response to a first refresh command during a refresh time;
• storing in a buffer a first data stored at a first address of the memory device during the refresh time;
• and
• writing a first error pattern at the first address of the memory device,
• wherein the refresh time is longer than a first refresh time, which is a minimum time for the memory device to perform a refresh operation.