> All this happens on a copy of our program. Self-modifying programs were fine under MS-DOS, but modern operating systems won't let it fly. Renaming or overwriting is fine, since the original file is still unchanged.

This isn’t strictly true: Linux, for example, provides `process_vm_writev`, which can be used to dynamically poke the executable text at runtime. The Linux kernel itself even has a decent amount of SMC, although it doesn’t use that mechanism.

The `totally_safe_transmute` party trick[1] from last year uses a similar technique. Technically it’s on data and not code, but the effect is the same.

[1]: https://blog.yossarian.net/2021/03/16/totally_safe_transmute...