Burroughs (Unisys) medium systems are three-address computers. The IBM 360 and its successors are two-address computers. Most computers are one- or two-address machines. In my view, the RPN calculator owes about as much to the venerable mechanical calculator, and to a number of anonymous designers, some of whom worked for Friden, as it does to Jan Lukasiewicz."Īlthough algebraic expressions may be processed by simulating a stack on any computer, very few computers are true stack machines at the hardware level. But ignoring the foundations on which this accomplishment was built serves no purpose.
HP provided many features in a truly concinnate way. They avoided many of the pitfalls that lesser minds would have become mired in. " Hewlett-Packard Company is to be commended for the beautiful design of the original HP-35 calulator (c.1972). The instruction booklets with these two calculators make no mention of RPN or Jan Lukasiewicz." " Around 1966, the Monroe Epic calculator offered RPN with a stack of four, a printer, and either 14 or 42 step programmability. The same orientation is used in instruction books for HP calculators, perhaps by coincidence." Furthermore, they are shown upside down, that is, the last-in-first-out register is at the bottom. The EC-130 has RPN with a push-down stack of four registers, all visible simultaneously on a cathode ray tube display. My first experience with RPN involved a nice old Friden EC-130 desktop electronic calculator, circa 1964. Aside from the apparent contadiction in these two statements, I do not think that either of them is quite true. " In their advertisements and also in a letter to me, Hewlett-Packard Company (HP), the best known manufacturer of RPN calculators, says that RPN is based on a suggestion by Jan Lukasiewicz (1878-1956), and that RPN was invented and is patented by HP. He starts with a history of RPN and I quote: Ball, Wiley Interscience, 1978, ISBN 0-8. I have a copy of the book "Algorithms for RPN Calculators" by John A.