Well this is disappointing. While trying to loosen up stuck mechanisms a few teeth broke off of an important gear. Guess this is now a parts machine.
I don't dispute that jails are hard to break into, but they are even harder to break out of. How many of us would choose to live in a prison in real life? Instead we make risk assessments that balance personal freedom and security, and the digital world should be no different.
To close out this thread, here is correspondence between Felt himself (the inventor of the Comptometer) and Zenith Pub. Co.
Even though I have more "advanced" mechanical calculators like my Monroes, the more I use this Comptometer the more impressed I am at the design. It's actually faster to use than my Monroes, at least for addition and multiplication.
Experts would only use the bottom rows so their hand was stationary. To enter larger numbers they'd enter two smaller numbers so to enter an 8 they'd enter 4 two times. This and later models had features to catch "fat finger" errors and partially-depressed rows.
Division was possible via repeated subtraction starting from the left and shifting to the right. There were no underflow bells, you'd just have to know when to stop subtracting a row. This is hard to do one-handed so I didn't film a video of that.
Subtraction was weird. You'd subtract w/ addition by the complements method, but would first subtract one from the number, then press down that number using the small digits on each key. You also slide the correct metal tab at the bottom to stop the carry. Here's 9 - 2.
You can perform many calculations surprisingly quickly and w/ one-hand. A well-trained Comptometer user was probably as fast as you'd get until electromechanical calculators. Here I'm calculating 1024 x 768, which just requires pressing 768 a few times and shifting left.
The Comptometer had a superior design. Pressing a key immediately updated the register, no need to pull a lever (the lever here clears the register). This design was so effective it stayed essentially the same (with minor improvements on error prevention) through the `50s.
I didn't realize just how much I blamed Microsoft for the current state of passwords until I sat down to write about their "passwordless future": https://puri.sm/posts/microsoft-ruined-passwords-now-aims-for-a-passwordless-future/
More than 26,000 PG&E customers were without power in the Bay Area today because of fog and mist. Fog. and mist. https://www.nbcbayarea.com/news/local/over-28000-customers-experiencing-power-outages-due-to-fog-mist-pge/2660562/
This is the carry mechanism for the Monroe. The bars form a wave and the last few move, but were completely seized up. A few hours with some oil, pliers, a screwdriver, and ultimately a heat gun, and it finally loosened up. Subtraction finally underflows all the way to the left!
To elaborate, this is a disposable VM just for opening random, possibly untrusted links other people send me. I do most of my own browsing in a different VM with ad and javascript blocking in place. It's always jarring to see just how bad the web is without all of that in place.
Technical author, FOSS advocate, public speaker, Linux security & infrastructure geek, author of The Best of Hack and /: Linux Admin Crash Course, Linux Hardening in Hostile Networks and many other books, ex-Linux Journal columnist.