Forwards-compatibility is hard

Forwards-compatibility is hard

You also get into having to think about what might be different in the future; for example, I've seen problems with an algorithm in the late 1990s that assumed x87 FPUs and was reproducible on all x86 CPUs of the era, but not on future x86 family CPUs (using SSE2 instead of x87), or on MIPS CPUs.

And then there's things like using 32 bit counters because you can't overflow them in reasonable time; this is true when things are slow enough, but as they get faster, it can become false. For example, an Ethernet packet is a minimum of 672 bit times on the wire; in 1995, a 32 bit packet counter represented over 8 hours of packets at the maximum standardised rate. However, today's maximum standardised rate (from 2024) is 800 Gbit/s, or overflow in a bit over 3.6 seconds.

The best we can reasonably ask for is that it's possible to follow your documentation and reproduce your results - that can include documenting the hardware, OS and other details of the system you produced the result on. That way, it becomes possible for a future reimplementation of your algorithm to do the A/B comparison between your system, and their new system, even if they've had to get help from a museum to build up the required hardware to reproduce your results.