The calculator I always wanted

[johnksellers]

Quote:I’m guessing I’m the only person on this forum that learned RPN on a TI-89. rpn89 by Lars Frederiksen

I cut my teeth on HP's first RPN hand calculator the HP-35. It was an exciting and wonderfully designed device, having only one memory register and a short RPN stack. But it was theoretically impossible to do the function calls, calculations, and data entry with fewer key presses. What an early marvel! It replaced the old desktop cathode-ray tube Friden.

When I was just entering college me and my parents were entertained by a college professor who showed off his multi-thousand dollar desk top Friden Calculator. It had one memory register and displayed 4 registers on a cathode-ray tube screen which was an RPN stack. He sat there with his bulky paper ledger where he recorded his calculations for his high-contrast microscope optics design, completely designed using the Friden.