[vcf-midatlantic] Slide rules, lots and lots of 'em

Dan Roganti ragooman at gmail.com
Wed Nov 8 07:36:04 EST 2017

On Wed, Nov 8, 2017 at 7:10 AM, Neil Cherry via vcf-midatlantic <
vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:

> On 11/07/2017 10:40 PM, Dave McGuire via vcf-midatlantic wrote:
>> On 11/07/2017 09:36 PM, Glenn Roberts via vcf-midatlantic wrote:
> Ah a fellow RPI'er!  I was one of the minions lugging my Keuffel & Esser
>>> up and down
>>> the hills of Troy, but lo and behold a piece of pocket-sized engineering
>>> beauty began
>>> to appear on campus (among those lucky, or rich enough) - the HP-35
>>> "slide rule"
>>> pocket calculator!  It would be a few calculator generations later that
>>> I could
>>> afford one (the HP-21) but I was hooked for life on HP and RPN!  Nothin
>>> like em!
> Right there with you on that.  I use an HP-48GX at my desk, an HP-41CV on
>> the RF bench,
>> and an HP-49G in the calibration lab.
> I'm running Droid48 on my Android Phone.
> Still have my HP21C (I think it's a C might be an S, with the broken door).

​This subject of RPN, Slide Rule, Algebra​, calculators never gets old for
me. I've used Slide Rulers in the past, and the RPN calcs too. But my
background was first in mathematics and physics before transitioning to
engineering. The view of the how the role of RPN calculations and
traditional mathematics coexisted was interesting. My classes involved
algebra,trig,and calculus taking precedence. If you noticed the equations
are never written in RPN. But RPN is easily used for computations, as on a
Slide Rule - except there aren't any function keys :) You can say that RPN
is more of a Low-Level [microcode] form of computing, where the actual
steps can be correlated 1-1 to the actions of the ALU inside the CPU.
Whereas the traditional mathematics is a form of High-Level programming
language, the firmware in your computer is capable of translating the
algebraic expressions to perform the RPN functions in the background.

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