I have been a devotee of calculator RPN notation since the mid 70’s. My first HP calculator was an HP 25C. For those who aren’t sure what it means, RPN stands for “Reverse Polish Notation”. For an eternity, in electronic industry years anyway, Hewlett Packard offered a variety of advanced calculators that used the RPN data entry format. Over the last 10 years or so, this blessed notation has been going the way of the Dodo.  Gradual extinction. 

As they explain it on the HP Museum of Calculators web site, RPN was named after a Polish mathematician named Jan Lukasiewicz who developed a logic in the 1920’s that allowed for the removal of parentheses in calculations.   Years later, computer scientists were able to apply the unique juxatposition of operators to the operands in first in last out (FILO) recursive stack manipulations. 

HP maintains that the term RPN is a type of homage to Lukasiewisz, and it may very well be. But, why isn’t it just “Polish Notation”? Here is my guess.  Up through the early 1970’s, the Archie Bunker years, Polish jokes were quite popular. In those days it wasn’t unusual for oddly configured devices to be referred to disparagingly with the adjective “Polish” and an especially strange contrivance might be further described as “reverse Polish”. My guess is that the word “Reverse” in RPN was from this vein of English usage.

I write to lament the decline of this intuitive and useful mode of computation. My guess is that onslaught of Japanese calculators (Sharp, etc) into the US market from the 1970’s onward with their algebraic entry format was an easier sell to the mathphobic masses.  Death by faint marketing.

College bookstores still offer a few versions of the RPN calculator and OfficeMax does offer the HP12 business calculators. But sadly, there does not appear to be any kind of revival anytime soon. There may be pockets of users out there, but we seem to be getting fewer in number.  It’s fun to watch people borrow your RPN calculator only to find that there is no “=” key. They quickly hand it back, grumbling as they look for another.