US Patent 7984355 Memory module with ranks of memory chips

A memory module includes a plurality of memory devices and a stacked error correction code memory device. The plurality of memory devices includes one or more memory chips arranged in a plurality of ranks. The stacked error correction code memory device includes a plurality of error correction code memory chips. The number of error correction code memory chips is at least one more than the number of the one or more memory chips. Each of the error correction code memory chips are arranged together with the memory chips of one of the ranks.