For everyone who is asking about division by zero, I answered it at 24:06, though you may not appreciate the answer without watching the entire portion where I cover how it works while it is disassembled. ~23:10, it's the result not the dividend
Unrelated but I wanted to ask anyway, you mentioned in your DLT video you were gonna make a video about tape drives on linux, just wondering if you remember XD
The truly fascinating thing is that division by zero does kind of work. The answer is infinity, and if you keep pressing the level, you're continuing to approach infinity. The problem is you'll just have to keep pressing forever.
Because it looks like Bohn designed that particular calculator in such a fashion (no pun intended) that it looks timeless, atemporal. Another example of such design are road signs on a typical motorway. Its font is intended for it to look modern and to make them as durable as possible, since there's no need to replace them as they look contemporary regardless of the time.
I've performed that foam repair myself on my Bohn Contex 20. There was foam in the peg board originally but its polyurethane foam, so by now it wont be so much foam as paste. These calculators were cheaper than name brands like Marchant, Friden, and Monroe, so instead of using spring retained pins like most 10 key adding machines they used foam to hold the pins in place by friction
35:52 "[...] and you would lock the lever down so you could carry it in the case with it being a little bit more compact." Not just that, but also to reduce the risk of accidental damage during transport.
34:08 by not adding the leading zero, you've effectively divided by 120, giving you a result of 1 with a remainder of 24. By pressing →(next) you are now dividing the remainder by 12, giving you 2 with a remainder of 0. So it works just the same as long division on paper!
Such beautiful machines these later mechanical calculators are. What I think I love most about them, beyond of course their mechanical nature (I'm a typewriter fan as well) is the fact that all of the logic in them is the core of computer technology -- these machines, as basic as they are can still be classed as computers in a sense, and when you scale it up to trillions upon trillions of crazy little operations following the same key structure (give or take) you have the core of every computer system ever devised. Just take those results and give them a meaning beyond binary data :D
Pro tip: most typewriter repair blogs that I've read recommend using gun oil when typewriter oil is called for. It's the closest modern equivalent. They also recommend gun cleaner when you want to remove said oil if it gets gummed up. Specifically, Rem-oil often gets mentioned, which comes in a spray can (perhaps not wholly coincidentally made by the Remington firearm company, which happened to also be the manufacturer of the first mass produced typewriter.) If that's the recommendation for typewriters, you may want to look into it as a solution for older adding machines like this. Final PSA: many typewriters don't require oil! Always research whether or not your specific model requires it, as some are designed to run dry and oiling will gum up the mechanism.
That's pretty impressive that it can do subtraction directly. Most mechanical calculators and adding machines had a weird thing where you have to add "complimentary numbers."
This is absolutely beautiful. Mechanical calculators are such nice beasts to see in operation. Thanks so much for the thorough explanation, your passion and enjoyment for this equipment shows!
one hint: Grease and oil play a different oil in machines and mechanism. Do not oil mechanism that are greased, as the oil acts as a grease remover. The worst thing that can happen that you oil a permanently greased part, it works fine, but then seizes up over time, because the oil has displaced the grease and then the oil runs away, resulting in the seizing. The issue with that is, that when you oil, the machine starts to run smoother makeing you think that oiling it was good, but in reality, now the mechanism needs regular oiling. An example are squeky doors: Factories fresh hinges are greased, so they do not squek. Over decades, the grease looses lubricity, the door hinge starts to squek. The hinge gets oiled - but from now on, the hinge has to be oil regularly. If the hinge would be disasemmbled and greased, it would not need grease or oil for decades agains. Note that grease can accumulate dust - so using oil as a greaser remover can be good for that purpose. (The worst for greased mechanism is WD-40. WD-40 acts as an oil and grease remover - it temporarily lubricates, but in reality, it just removes any residual oil and grease)
I have the electric model, and when you multiply, you enter the multiplicator on the keyboard and it repeats adding the multiplicand and shifts the register automatically. This is one of the cleverest devices I have ever seen...
I used to work with my Dad who was the County Forester. I remember when the county bought him a Bohn Contax calculator to use on his job It was funny operating it. We entered the numbers in then pumped the handle until it locked up and the answer appeared in the window! LoL
This machine knows the steps of the solution, that is, it does not only give the output! It would have improved and developed more if they had not abandoned it! Trust that, electronics are structurally more complex than this machine.
And that, boys and girls, is how to program in 8 bit assembly. Go forth and make great things! :D Very cool seeing that machine function. The sheer complexity of it must have been very daunting for period manufacturers.
The left-pointing arrow is not exactly the same as pressing zero: it takes care of resetting the counter too! (the other arrow does it as well) You need that feature while multiplying and dividing.
You know, I'm pretty sure I've stumbled across your channel before returning recently. Anyway, glad to see you back in my recommended videos. Also, yes I did watch your recent video explaining the choice of your name.
It's weird how much I am into calculators, even though I hate math class, and could never do most of what they did, most times having a d in math, and once got an a somehow.
my eyes are already glossing over... kudos to the people who used this to run an office or business all i can say is thank god electronic calculators became a thing
I was wondering about mechanical calculators for quite some time, thanks for the video. however, my imagination/guess was something made with rotating gears and some such. i think i got that "guess" from glimpses shown in some video i saw
Thank you for opening it. That was risky, if a spring flew out or a cog dropped then it would be effectively ruined. I imagine all the engineers for that thing are now dead or ga-ga.
I think it could be interesting to write an emulator of this calculator, to preserve how it works digitally. Definitely got to have the sound effects for the key presses and plunger.
Wow i still got confused how this thing works and how to work with it, but it’s an interesting device, and eventrough the technology wasn’t there to calculate reliably but this can be considered as the most advanced analogue computer i,ve ever seen.
No... when *I* hit the lever the 65535th time, my cat hit the clear register button and the display became zero, so when *I* divide by zero, the answer is 65535
I have Contex 10 too, but I have got an issue with the cycle counter which doesn't turn enough and sometins does not turn at all. Have you got an idea to solve this issue ?
now this is proof positive that math is hard. thanks to modern technology ("Modern" being from the last 50 years) calculators actually calculate. This machine is from an age when you still needed to think even when using a machine. You're basically 'programming' a mechanical keyboard to do a calculation. you aren't just entering in digits and telling it what operation you want to end up with. It's mind boggling when you think only 12 years later from this machine being new we landed on the moon. Just furthering the genius of those engineers involved. I wonder if we'll get to a point in the future where computer programming that we know today will be seen as overly complex and clunky in the same way that this calculator looks like such a hassle to use. "Grandpa? You mean to tell me you had to manually type in thousands of lines of code to make a video game? Didn't you have conceptual neural interpreting language?"
I do enjoy the (sometimes) overly complicated nature of some of these things. Even if we do have a conceptual neural interpreting language in the future, I'll always choose the code. :D :P
Back in the NES days, games were programmed with assembly code, which is the lowest level language, very close to the hardware, and is really hard to program in. You could allegedly develop games for the SNES with the C language, which is still somewhat low level, but most games were still assembly. Games only started really using C for stuff like the PlayStation 1. If you wanted tools, such as a level editor or just something to organize your code with, you'd most likely have to make it yourself. Nowadays very few people would go out of their way to program a game in just C or assembly. Game developers use stuff like Unity, Godot or Game Maker, which helps manage stuff like objects, assets and code for you, and lets you do 3D without doing some serious engineering. Things don't seem to really have changed much beyond that in the last 10 years though. You could definitely do a lot more in any engine nowadays than you could 10 years ago, but in terms of what you'd actually have to do to make games, it seems that we've decided that "Specify your logic for each thing" is the most abstract we're willing to go, and the best way to specify logic is to use things somebody else had built, or to write code for it.
The interesting thing about mechanical calculators is the fact that digital calculators themselves still operate identically. For example, when he subtracted a larger number from a smaller one to achieve a negative number, the output register rolled over from the highest possible value minus the difference from the numbers. In a computer, the output register holds an identical result (i.e. 4 - 6 -> 999...998), but computers are able to recognize this with a bit of trickery to tell the computer that the number in the register is actually negative, so it shows instead shows -2 instead of 999...998. Likewise, multiplication and division really are repeated addition and subtraction. Pretty cool stuff.
Clorox Bleach, exactly. It’s hilarious the cognitive dissonance people have. CNN has a 5 second delay interviewing someone in London in 2019, but people think Nixon had a real-time zero delay phone conversation with the moon in 1969. LOL
This machine knows the steps of the solution, that is, it does not only give the output! It would have improved and developed more if they had not abandoned it! Trust that, electronics are structurally more complex than this machine.
I wonder how this thing compares to a Curta, which is one of the few other mechanical calculators I'm aware of. I have never owned a mechanical calculator save for an abacus, and I'm not even sure that one was "mine" mine instead of family property. Is there anyone who has laid their hands on both this and the Curta and could say how they compare? I'm asking especially because the Bohn Contex 10 does seem to require a degree of special-casing and operator awareness, but it does look more familiar and more like a typical calculator than the hand-cranked Curta. But which one would really have been easier to use and easier to learn? Does anyone know?
How does it give you a division answer higher than 9? Edit: I didn’t quite watch long enough before asking. At the very end of the video after the tear down he explains that it feeds the answer back one digit at a time. Clever.
This machine knows the steps of the solution, that is, it does not only give the output! It would have improved and developed more if they had not abandoned it! Trust that, electronics are structurally more complex than they are.
I don't own a mechanical calculator, I've never used one, I've never even seen one in person-the best I can say is I've played with a software emulator of a Curta-but it's pretty neat that it's basically a more user-friendly "packaging" of, for example, the designed-in-1936 Facit TK, which you can see in CuriousMarc's video at ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-cRGu1OBFPrc.html . XD
since it carries division by the actuator. what happens if you were to. say accidentally (or intentionally to test) divide by zero first. adding a subtraction counter. and then divide by your actual number? would it read the division correctly or account as if added by 1?
Was this thing ever popular? Like... at all? Coz fuck that... I didn't very much like math in school, this has not improved that...The engineering is fucking mind blowing though!
Didn't know how lucky we are for having electronic calculators :) That thing is horrible ! I mean is nicely builded but the workings is too complicated and prone to errors.
This machine knows the steps of the solution, that is, it does not only give the output! It would have improved and developed more if they had not abandoned it! Trust that, electronics are structurally more complex than this machine.
5:44 “ say you want to subtract something! So now you have to push the, subtract button!” Really?! No shut , Sherlock!! 😐 Noooo, I thought 💭 to subtract something you pushed the multiply button! 😕
