I had one of these way back when, and loved it.

This is a great article, and reading it might give younger folks an idea of why HP users from the 1900s loved their calculators so much. They were designed for people who needed to get things done. And it wasn't just the algorithms inside. The physical machines were terrific, too. The pivoting keys left no doubt as to whether you had entered a digit (or whether, as in competitors' machines, the keystroke had entered the digit twice by mistake). And then there's RPN. Oh, lovely RPN -- trusty friend to those who needed correct answers and needed them in a rush.

Such elegance (of machines and writing) is rare nowadays.

Thanks for posting this, which brought back good memories.