Method of adjusting read voltages applied by a nonvolatile memory device using information stored by a read history table

An operating method of a memory controller which controls a nonvolatile memory, the operating method comprising:

• reading data stored at the nonvolatile memory based on a plurality of read voltages;
• adjusting, in response to determining that the data includes an uncorrectable error, the read voltages based on a previous read history table and a first reliability parameter to read the data using the adjusted read voltages;
• detecting an optimal read voltage set in response to determining that data read using the adjusted read voltages includes an uncorrectable error;
• and
• updating the previous read history table to generate a current read history table, based on the detected optimal read voltage set, a second reliability parameter, and the previous read history table.

An operating method of a nonvolatile memory device which includes a plurality of pages and an error correction circuit configured to correct an error of data, the operating method comprising:

• receiving a read command from a memory controller;
• reading, in response to the read command, data stored on at least one of the pages based on a plurality of read voltages;
• adjusting, in response to determining that the data includes an error uncorrectable by the error correction circuit, the read voltages based on a previous read history table to read data stored at the at least one page using the adjusted read voltages;
• detecting an optimal read voltage set in response to determining that data read using the adjusted read voltages includes an error uncorrectable by the error correction circuit;
• and
• updating the previous read history table to generate a current read history table, based on the detected optimal read voltage set, a reliability parameter, and the previous read history table.