Why doesn't Python's mmap work with large files?

Question

[Edit: This problem applies only to 32-bit systems. If your computer, your OS and your python implementation are 64-bit, then mmap-ing huge files works reliably and

Answer 1

The point you are missing is that mmap is a memory mapping function that maps a file into memory for arbitrary access across the requested data range by any means.

What you are looking for sounds more like some sort of a data window class that presents an api allowing you to look at small windows of a large data structure at anyone time. Access beyond the bounds of this window would not be possible other than by calling the data window's own api.

This is fine, but it is not a memory map, it is something that offers the advantage of a wider data range at the cost of a more restrictive api.