Understanding the difference between storage (disk) and memory (RAM) is crucial. Memory operations are faster but volatile, while storage is persistent but slower. In performance-critical applications, keeping frequently accessed data in memory and minimising storage I/O is essential for speed.

Example:

1import mmap
2
3with open("data.txt", "r+b") as f:
4    mmapped_file = mmap.mmap(f.fileno(), 0)
5    print(mmapped_file.readline())
6    mmapped_file.close()

Memory-mapped files allow you to treat disk storage as if it were memory, speeding up access times for large files.

References