mmap
メモリマップトファイル - Wikipedia
pythonでの利用を考えると、
numpy.memmap — NumPy v1.15 Manual
python - Can memmap pandas series. What about a dataframe? - Stack Overflow
DataFrame is NOT a collection of series but a collection of similarly dtyped matrices.
It can do that without copying the memory ONLY if a single ndarray matrix (a single type) is provided.