advantages of RPN

[Mike Morrow]

(05-21-2014 10:20 PM)Tugdual Wrote:  I personally don't value the number of keystrokes to distinguish RPN from other systems. It was interesting to see that if this number is always lower for RPN, it is not very different (<10%) and shall not explain all.

That less than ten percent difference that you cite is inaccurate in the extreme, in my personal and fairly extensive contemporary experience.

In 1977 I purchased the new HP-67 (the first HP that I owned, and the first RPN programmable I'd ever used) and the new TI-59 (my third TI programmable, after a SR-52 and SR-56). I was experienced with TI programming well beyond my familiarity with HP RPN programming.

I wrote equivalent programs for both machines for use in the engineering department of a USN nuclear submarine between 1977 and 1979. The USN used NO digital computers in its nuclear propulsion plants of that era. My programs performed such tasks as nuclear power plant calorimetric, machinery vibration data processing, radiological laboratory analysis calculations, and others. For ship driving, I wrote several programs, such as calculating bearing and distance for closest point of approach.

These were professional-use, frequent-use programs, not programming exercises. I consistently found, without exception ever, the number of steps that the HP-67 required for any specific process was about 65 percent of the steps required by the TI-59. That 35 percent differential in the HP's favor was very helpful because the HP-67 had far less RAM than the TI-59. The biggest advantage of the TI-59 was its memory size, and much more...the PC-100A print cradle. The advantage of the PC-100 was so great that I intended to settle on the TI-59 as my standard machine for these shipboard tasks. But the TI hardware was far far less reliable than that of the HP-67, with several failures experienced in a one-year period of either the TI-59 or PC-100A for critical service needs. I was forced to use only the HP-67, which never failed, for every task. Eventually I was able to get the ship to purchase an HP-97 to get printer capability.