that meant that source code on machine X may not generate the same results as on machine Y. Machine X will probably do what Machine X does repeatably!

"platform-specific" or "not portable" are common terms to describe this.

I think the whole idea of this thread was that when you are dealing with either very big or very small numbers, there are a lot of ways to "get into trouble"

I don't know to what large numbers, small numbers and trouble you are referring. I did not get any such idea from this thread. Quite the opposite, the OP's question was about a feature that *prevents* you from getting into trouble in a particular situation.