This is Dan’s site which is mostly about HP RPN calculators, but may also feature rants about: Linux; networking; microcontrollers; electronic fuel injection / engine control unit software and hardware; and anything else that’s worth writing or ranting about.
Yes totally, ENIAC had a 100kHz clock in 1945. Only 30 years later the HP-35 was a consumer device running at 200kHz that could fit in your pocket and totally annihilated the slide-rule market. The historical significance of these devices is immense.
While we usually view mathematical problems as being algebraic and RPN is born out of computing restrictions of the time it is actually a far superior and more user-friendly calculator interface in comparison to algebraic. I’ll make and argument for that here.