What is old is new: RPN on the HP 35s Scientific Calculator

When I comment on technology, I like to discuss the good and the bad about it. I don’t sell calculators, and I don’t get freebies to review. That gives me the freedom to freely comment.

Click on the graphic to go to a lengthy review on this calculator.

One has to admit that for HP to sell a $90 RPN calculator in this age of $20 textbook display calculators takes guts, especially if said $90 calculator does not have graphical capabilites. HP has been making RPN calculators since the 1970s. In the 80s, they had their heyday when their top-of-the line calculators not only had programmability, but even came with complex functions stored on cards on which was mounted a piece of magnetic tape on the small plastic card which one would swipe through a reader inside the calculator. Every key including the number key seemed to have at least 3 functions, and usually 4.  It was a great technology, but the calculators were quite pricey, but loved by statisticians, university professors and math nerds everywhere.  The common theme in all of these calculators was that their input was required to be in reverse Polish notation, or RPN.

In RPN, you enter buy tramadol cheap your two operands, and press the button for the operator last. This requires an “Enter” key; and since the calculation is over once you press the operator, there is no need for an equal sign. In fact, the keypads are noted for their lack of an equal sign.

On a normal calculator, entering “2 + 2” is a matter of entering the operands and opereator in the order you would write them down. For RPN, you enter “2 2 +”, hitting an “Enter” button after each “2”. The advantage of RPN, to those who have the patience to give themselves such a habit of thought for this, is that the overall effect is that you can do a reasonably complex calculation with fewer keystrokes, than on a conventional calculator. And while it promised efficiency, it was never a calculator for button monkeys. To take advantage of  RPN’s efficiency you always needed to think carefully about the calculation. But I must state that HP is ready for today’s generation: they do in fact, provide an “algebraic” mode where it uses the common algebraic syntax you would expect on most other calculators, but on my calculator, it was RPN that was the default.

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