Joseph II, RPN is Reverse Polish Notation. It’s just a method of entry that used to be popular on calculators, but has largely been abandoned in favor of modern algebraic entry. The basic idea is that the calculator maintains a stack and all operations are performed on the top two elements. For example, instead of 2 + 2 = to get you 4 on a modern calculator, on an RPN calculator you’d type 2 = 2 +: first the calculator would pop the 2, pop the 2, add them together, and then push the 4 onto the stack. Hewlett Packard is the lone holdout, and all their calculators today still use RPN.
My point was, though, that there used to be a limit on the elements the stack could hold. Eventually, the memory doubled, enabling one to hold twice as much data, but shortly thereafter, the calculator began using 32 bit numbers instead of 16 bit numbers, so the doubled memory once again held only half as many numbers.
It reminds me of what a famous philosopher once said (I think it was Plato, but I can’t find the source right now): “Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Curabitur luctus congue tortor. Integer vitae dolor.” Roughly translated that means, “That which was once small can become bigger, but it will remain the same size.”