I have just a question of understanding. I'm referring to the fine documentation of José Lauro Strapasson http://thomasokken.com/free42/42s.pdf
According to the chapter 2.8 The Stack, the HP 42s has the following behavior:
There are really things I don't understand.(...)
But since the calculator’s display has only two lines just x and y lines are visible. When you enter a number (say 2 ENTER) what happens is the following.
i) The content of lines t and z are lost.
ii) The content of line y goes to line t.
iii)The content of line x goes to line z.
iv)The content just entered goes to line y and line x.
So what you just entered appears twice. So if you do 2 ENTER + you will have 4 as answer. This is a feature, a bad feature I think, of the HP RPN style used by the 42S (also in the 33S, 12C, etc but not in the HP48 or 49).
First of all: the described behavior of the stack xyzt according to i) - iv) is in my understanding completely different. If I have a look at the DM42, which always shows the whole stack (what a manifesto to RPN ), the stack ist simply some sort of lifo stack. There is no copying, deleting and moving around as described in that documentation.
My HP12C has the same behavior and as far as I remember my original HP11C had the same.
The second point is: he mentioned there is a better way to do RPN and it was implemented in HP48/49. Now if I look at my HP17Bii+ in RPN Mode, it seems exactly the same to me as it is in the other HP RPN's I had and have. So either this one has also a "bad" feature or there was just a short time where it was different.
Last but not least: What is bad on the behavior of these calculators? Maybe I just got too much used to the way it works so that I don't see the point anymore.
I hope that's not a question of faith... It's just I don't understand what José Lauro Strapasson tries to tell me there.