Data memory device and method of programming to the same

A data memory device, comprising:

• a memory element array including an array of a plurality of memory elements each capable of storing M-value data (M being a natural number not smaller than 2);
• a data storing unit configured to temporarily store program data to be programmed into the memory elements;
• and
• a data processing unit configured to execute a data process on the program data,
• the M-value data being composed of first data to M-th data, the first data being data giving a largest physical impact on the memory elements when programmed thereinto among the first data to the M-th data,
• the data processing unit being configured to be able to execute a data process on an aggregate of the program data stored in the data storing unit, and the program data to be programmed into memory elements,
• the data process being conducted to determine which of the first data to the M-th data is least existing data, the number of pieces of the least existing data being the smallest in the aggregate of the program data,
• the data process including a first data process and a second data process,
• the first data process being performed, when the least existing data is data other than the first data, to replace the least existing data included in the aggregate of the program data with the first data and replacing the first data included in the aggregate of the program data with the least existing data;
• and
• the second data process being performed, when the least existing data is the first data, to maintain the aggregate of the program data as it is without executing any data replacement thereon.