Thread: Help finding old calculator...

Originally Posted by Kriton

When I actually used and cared about mathematics in my first lonely year as a lost AE student at Syracuse, I could not be parted from my HP 11C - the clunky size, the reverse Polish notation (not a racist comment, but what it was called those of you with very thin skins) - never knew why is was called Polish anyways, it was just weird, but cool.

I still have my HP11C, bought in 1985. It's been used hard for a large chunk of that time, and is still on its original batteries.

A lot of the cult-of-HP comes from that level of build quality, and a lot of it comes from the RPN notation, which takes a little getting used to but is extremely flexible and powerful in actual use.

So to calculate (1+2)*(2+3) you would:

a) normal calculator of the day: 2, +, 3, =. store, 1, +, 2, =, *, recall, =
b) HP RPN calculator: 1, 2, +, 2, 3, +, *
c) modern parenthesizing calculator: (, 1, +, 2, ), *, (, 2, +, 3, ), =

The RPN calculator has them all beat for speed, and is an even bigger win once the calculations get complex - even something like "5 + ((1 + 2) * 4) − 3" could get pretty annoying with a normal algebraic calculator of the day because you would generally have to calculate the parenthesized pieces separately and write them down, then re-enter these values to calculate the final value of the equation, while the HP could evaluate it in one pass: "5 1 2 + 4 * + 3 -".

It's called Reverse Polish Notation because it's a reversed form of Polish Notation, which is so-named because its inventor was the Polish mathematician Jan Łukasiewicz. At one time I made a decent living programming in the Forth programming language, which was an entirely reverse Polish notation language. The programming language Lisp is a nearly exclusively normal Polish notation language.