[ale] Engineering Archaeology

[lollipopman691]

I believe I am the last generation to actually use a slide rule in class.  College class of 1980.

BTW all numbers in OpenSCAD (https://openscad.org) are 64 bit IEEE floating point.  I just gave an OpenSCAD talk to DC404 ( https://dc404.org ).  Pretty Fun.

-- CHS




On Sunday, January 18th, 2026 at 11:51 AM, Jeff Lightner via Ale <ale at ale.org> wrote:

> 
> 
> I owned a slide rule in high school but electronic calculators were around by the time I was a senior so I was never terribly proficient with it.
> 
> The well to do kids were buying the high end TI calculators but I could only afford a model with basic functionality. It weighed a lot and the battery didn't last long. That was back in the days they would blank the display after a few seconds of inactivity, trying to preserve battery.
> 
> It was just as well though. In my math and science classes we weren't allowed to use devices when doing calculations on tests so it forced me to do things by hand.
> 
> Later in my hospitality/accounting career they initially didn't have electronic or computerized systems early on. Many of the financial books and reporting I did were done by hand. As time went by electronic systems appeared and quickly evolved to computerized systems. I always had to laugh when the computer went down as co-workers would say we couldn't check people in or out. I explained that hotels actually existed long before such systems so it was in fact possible.
> 
> -----Original Message-----
> From: Ale ale-bounces at ale.org On Behalf Of jon.maddog.hall--- via Ale
> 
> Sent: Sunday, January 11, 2026 1:44 PM
> To: Atlanta Linux Enthusiasts ale at ale.org
> 
> Cc: jon.maddog.hall at gmail.com jonhall80 at comcast.net
> 
> Subject: Re: [ale] Engineering Archaeology
> 
> 
> 
> "If we applied such logic to when we were starting out - "slide rules work just fine, don't need no electricity, storage, keyboards, monitors, etc."
> 
> Slide rules are an interesting example. Stop and think about the incredible application of logarithms being painted on two sticks, then slide those sticks back and forth to be able to multiply two numbers via adding two logarithms of them.
> 
> Genius.
> 
> And a fine example of analog mathematics being able to solve engineering issues.
> 
> Usually only used to calculate to three levels of precision, they were "good enough" to do the calculations in an age where three levels of precision was about all we could do in any type of manufacturing....so why calculate to any greater precision, whether you are manufacturing a door knob or a bridge?
> 
> Fast forward to floating point arithmetic in a computer. How many of us have fallen into the trap of trying to "equate" two floating point numbers, only to realize that "two" really has a value of "1.999999..something-mumble"
> 
> When I was teaching at Hartford State Technical College in 1975 the school store was cleaning out their inventory and found about ten beautiful "Aristo-Multilog Slide Rules", still in their box, complete with leather carrying case and instructions.
> 
> The store was selling them for five dollars each, down from their original price that was probably close to 100 dollars. I bought all ten, then gave them out as prizes to good students, showing them how to use them and explaining the significance in computer science. I have two left.
> 
> I did not expect the students to become as expert at using the slide rule as I was, but I was happy to see that they understood the significance of the lesson
> 
> md
> 
> > On 01/10/2026 8:36 PM EST Ron via Ale ale at ale.org wrote:
> > 
> > Jeff Lightner via Ale wrote on 2026-01-10 14:50:
> > 
> > > In my later years when I would speak to people about “the old days”
> > > and things such as RS232-C and/or Hayes modem commands I realized
> > > that while it was likely true I’d forget much of the detail it
> > > didn’t mean younger folks would never know more than I’d forgotten.
> > > They would instead have no need for what I’d forgotten (for the most
> > > part) and eventually would learn things I’d never learn.
> > 
> > Insightful comment.
> > 
> > Of course, usual disclaimers of "not everyone, not always, not
> > everything" apply:
> > 
> > The "kids today" are learning lots of great new things and pushing
> > boundaries in new directions. They're exploring new ways to do stuff
> > and aren't sold on "we've always done it this way, so we should
> > continue to do it this way".
> > 
> > Too often I see that attitude by other, fellow tech old-timers.
> > 
> > If we applied such logic to when we were starting out - "slide rules
> > work just fine, don't need no electricity, storage, keyboards,
> > monitors, etc." - I'm sure most of us would've found it unconvincing.
> > 
> > Let them have their chance, some ideas will work, some won't, and it's
> > their world now.
> > 
> > Anyway, appreciate the thought provoking post.
> > 
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