Memory system and method of accessing a semiconductor memory device

A nonvolatile memory device comprising:

• a flash memory device including a memory cell array including a plurality of multi-level cells;
• and
• a memory controller configured to control the flash memory device to program the multi-level cells by one of plural multi-bit programming methods with reference to a characteristic of data to be stored,
• wherein at least one of the plural multi-bit programming methods maintains least significant bit (LSB) data when there is a program fail with most significant bit (MSB) data.

A programming method of a nonvolatile memory device, comprising:

• selecting one of a plurality of multi-bit programming methods with reference to a characteristic of data to be stored;
• and
• storing data in a memory cell array using the selected multi-bit programming method, at least one of the plurality of multi-bit programming methods maintaining least significant bit (LSB) data when there is a program fail of most significant bit (MSB) data,
• wherein the plural multi-bit programming methods include first and second multi-bit programming methods, the first multi-bit programming method is selected if an address of the data to be stored is correspondent with a first area of the memory cell array and the second multi-bit programming method is selected if the address of the data to be stored is correspondent with a second area of the memory cell array.