Abstract: A memory module includes a plurality of memory devices, each memory device including a plurality of memory cell arrays, a plurality of data input/output lines, and a memory cell array select input line. The plurality of memory cell arrays are arranged as a plurality of blocks such that data transfer is enabled between a memory cell array in each block of the plurality of blocks and a respective data input/output line of the plurality of data input/output lines when a predetermined voltage is applied to the memory cell array select input line. The module includes a circuit substrate on which the plurality of memory devices is mounted, the circuit substrate including first and second voltage busses.