this post was submitted on 08 Dec 2023
372 points (96.0% liked)
Technology
59390 readers
2569 users here now
This is a most excellent place for technology news and articles.
Our Rules
- Follow the lemmy.world rules.
- Only tech related content.
- Be excellent to each another!
- Mod approved content bots can post up to 10 articles per day.
- Threads asking for personal tech support may be deleted.
- Politics threads may be removed.
- No memes allowed as posts, OK to post as comments.
- Only approved bots from the list below, to ask if your bot can be added please contact us.
- Check for duplicates before posting, duplicates may be removed
Approved Bots
founded 1 year ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
Analog computers are pretty cool, yet underrated tech. Although they aren't very flexible compared to digital computers in the range of what they can do, they do their specific use case very well.
Need to solve a partial differential equation in real time? Don't bother with iterative algorithms, that's fool's math, playa. Just hook it up to an analog computer specifically designed to solve that PDE type, rig up some wires for the input and output to your oscilloscope for real time mathz.
The old firing computers from WW2 are cool as hell.
Not just analog, but mechanical analog.
They take 25 inputs, some of which come directly from the spotter scope things, some from the ship itself, and then controls the guns directly.
It's all cams, gears, reciprocating whatsits and stuff.
And because it's analog, there is no quantisation, rounding errors, floating point errors. It's continuously and instantly calculated.
Very cool stuff.
https://youtu.be/s1i-dnAH9Y4
Very pretty stuff. I particularly recommend Ken Shirriff's Reverse-engineering the mechanical Bendix Central Air Data Computer:
He goes into detail about how non-linear equations are implemented using shaped cam gears (and how such functions can be difference-encoded against linear forms). It's insane.
Eh, I'd say that runout and stiction are their own demons with potentially more bias than those error types :) Not to mention temperature sensitivity -- hot days will give different answers to the equations!
Ha, oh yeh. Good point.
A bit of dirt throwing off the calculations.