> There are countless rare machines that your code doesn't run on--what's so special about big endian?
One difference is that when your endian-oblivious code runs on a BE system, it can be subtly wrong in a way that's hard to diagnose, which is a whole lot worse than not working at all.
That sounds like a problem to deal with as part of your paid IBM s390x porting contract. I guess my point is: why deal with this before IBM is paying you? No other big endian platform matters, and s390x users are 100% large commercial customers. If IBM or one of their customers isn't paying you, there's nobody else who would need it. If IBM is paying you, you can test on a real z/VM that they provide. I see big endian as entirely their burden now; nobody else needs it. If they want it, they can pay for the work.