That IBM ad at the end is priceless on so many levels.
(What did that massive computer do? How many female engineers do you count... etc,)
Thanks for the article. My grandfather was an accountant who preferred the slide rule to a calculator. I grew up with slide rules around me, and never could understand the logic.
Another tool lost in the past generation is the Abacus (here is a great story with Feynman[1]) and I would love more info as to how those compared in logic or use, if anyone can shed insight.
I believe it's an IBM 604 Electronic Calculating Punch. This box was programmed with a plugboard and did BCD addition, subtraction, multiplication and division. It was built from 1100 vacuum tubes.
It wasn't a computer in the modern sense. It read data from a card (the box in front is the card reader), ran through up to 60 steps of calculation, and then punched the result onto the same card, at the rate of 100 cards per minute.
This system was introduced in 1948 and rented for $645 a month (about $5500 in current dollars).
I have some of the same experiences. Every older engineer would say "When I was in school we used slide rules" but no one would ever explain how they worked. This article was great for finally clearing that up for me.
This surprises me. I went to school after electronic calculators replaced slide rules (and books of log and trig tables), but we still learned how logarithms worked and that they were the principle behind slide rules.
I graduated from college in 2016. We definitely covered logarithms but nobody really tied it back to slide rules. It definitely is a shame because understanding how problems were solved before can provide a lot of insight.
> My grandfather was an accountant who preferred the slide rule to a calculator.
This is hard for me to understand. Slide rules are inherently imprecise, in the same way floating point calculations are imprecise but much moreso. I'd expect an accountant to prefer integer (fixed point) math for the same reason banks do now.
Yes, they are imprecise. In general, you're limited to just three, maybe four digits regardless of the actual magnitude of the numbers and you have to keep the powers of ten in your head. Honestly, though, once you've used it enough, it isn't that hard to do. Besides, in most calculations, you don't need precision out to the 12th digit. After all, skyscrapers, bridges, and ocean liners have been built using slide rules for a long time and they, mostly, have worked just fine.
Imprecision is fine for engineering and can be compensated for. But this is not true for managing money, which is why floating point has historically not been used in accounting applications.
In some sense. A way to teach how a slide rule works is by using two rulers to create a slide rule that does addition. Most pupils will understand why that works. The jump from there to really understanding why logarithmic scales work is a lot harder for most, but I’m sure that intermediate step helps some pupils.
Oh, come on. I'm not talking about a home-brew slide rule or a virtual slide rule simulation. Obviously it is possible to make those. I'm talking about an actual manufactured slide rule sold as a product and used in a working environment to perform addition.
Most slide rules have a linear scale on them, but it is intended to be used along with a logarithmic scale for working with exponential/logarithm functions.
In general slide rules aren’t used for addition because 3-digit addition is very fast to compute mentally or using pen and paper.
I used to collect slide rules. I have never seen one with a linear scale, and I can't find any evidence on the web that any such slide rule was ever manufactured. So if you can provide evidence that you possessed such a slide rule, that would be of significant historical interest.
Isn't the "L" scale on a slide rule linear? See the photo at the top of the Wikipedia page [1] for example. (I may be confused here, since you know slide rules better than me.)
Sure, but to do addition you need two linear scales, one on the fixed part and one on the slider. The L scale is for computing logarithms, not for doing additions.
If the L scale is on the slider, and you’re not too much concerned accuracy (the procedure does 5 ‘align scales’ operations before the final ‘read the result’) one linear scale is sufficient, if you use the hairline on the cursor as a kind of memory:
”Example: calculate 0.23 + 0.45
- "Reset" the rule so that all the scales are lined up.
- Move the cursor to 0.23 on the L scale.
- Move the leftmost 0 on the L scale to the hairline.
- Move the cursor to 0.45 on the L scale.
- Reset the rule again so that all the scales are lined up.
- The cursor should now be at 0.68 on the L scale, which is the sum of 0.23 + 0.45.”
Using a sledge hammer, break the slide rule into N pieces, taking care to insure that N is greater than the sum you wish to compute. Now to compute the sum of A and B, count out A pieces into a paper bag, then count out B pieces into the same paper bag. Now empty the bag onto a clean workspace and count the total number of pieces to produce the result.
I checked, and sure enough you're correct. I could have sworn that I'd had two linear scales, but … I was completely wrong. Been decades since I used it, and the memories obviously faded.
Actually back then the "girls" where the computers imagine typing pool that did maths calculations Los Alamos had a large number to do nuke calculations.
The _Hidden Figures_ reminder there that women and people of color were job titled "computers" for a long time in the English language. The term for female/PoC programmers/mathematicians/engineers became the name of the machine built to replace them. It's a fact that feels increasingly strange with distance/hindsight, or at least it should to folks with a heart.
(Just finished Mary Robinette Kowal's excellent "Lady Astronaut" books, and they are a fascinating retro-history of a timeline that fought to get to Mars faster than ours, and an interesting part of that success was getting more Computers in space, but by that it was meant women and people of color that could use a slide rule and do important math quickly in a crisis.)
you are conflating history with sexism/racism, though they overlap. "Computer" was essentially a "technician" who performed calculations, as today you'd have a technician to install parts in your machines or do other mechanistic tasks in an operation. It's not so unusual for a word that refers to a human job eventually becomes the name for the machine that replaces that job: dishwasher, messenger, agent. "computer" happens to be the job that is so easy to mechanise cheaply that the human job was made quickly obsolete once the opportunity arose.
The term "Computer" long predated mechanical computers, by centuries.
https://en.wikipedia.org/wiki/Human_computer
The earliest "computer" jobs tended to exclude women due to sexism.
You're more likely to find women and PoC in "computer roles" than in scientist/engineer roles because they tended to be shut out from higher-level roles they may have been qualified for, leading to an oversupply of their demographic at the lower levels. And those overqualified women/PoC have more notable stories than the non-overqualified women and men in those roles.
Appreciate the extra technical details. The conflation is still a useful shorthand in terms of the discussion of the ad in question: it's wording specifically says "replace engineers" with this mechanical computer. You are right, it doesn't need to state "replace [humans] computers with [mechanical] computers" because that is already implied in the name choice.
Whatever the ratio of "over-qualified" human computers were at the time, it was still a non-zero number, and it is useful to remember those "notable stories". Even the "non-over-qualified" members not "notable" enough for memory weren't machines, and you can't claim they had no impact outside of "pure mechanistic tasks"; certainly there was a lot of under-appreciated QA/QC work and inter-personal labor that got shifted around over the years. Any loss of a workforce to automation isn't just "mere" obsoletion, because people aren't machines, and it is good to remember that (conflation, overlaps, or not). Especially for a word like "computer" as opposed to "dishwasher" where we practically never have a reason to "human compute" today, to pull out slide rules and step through some math. (There are still human dishwashers in major restaurants; we still have dishes in our homes that we manually wash in addition to machine washing.)
Thanks for the article. My grandfather was an accountant who preferred the slide rule to a calculator. I grew up with slide rules around me, and never could understand the logic.
Another tool lost in the past generation is the Abacus (here is a great story with Feynman[1]) and I would love more info as to how those compared in logic or use, if anyone can shed insight.
[1]: https://www.ee.ryerson.ca/~elf/abacus/feynman.html