When mechanical analog computers ruled the waves (2014)

https://arstechnica.com/information-technology/2014/03/gears-of-war-when-mechanical-analog-computers-ruled-the-waves/

by tosh • 8 years ago

43 15 8 years ago

arstechnica.com

dang• 8 years ago

Two previous discussions:

https://news.ycombinator.com/item?id=11460672

https://news.ycombinator.com/item?id=7419837

Animats• 8 years ago

This equipment in use: [1]

[1] https://archive.org/details/0436_Radar_Secrets_01_20_16_00

boomlinde• 8 years ago

The whole training film on mechanical computers, for navy mechanics I believe: https://www.youtube.com/watch?v=s1i-dnAH9Y4

It illustrates the problems and solutions near perfectly, and I've watched it way too many times.

nick_m• 8 years ago

Thanks, being a long-time lurker, I've just signed up now to say that's great. What a video - I've been writing software for the past 31 years, and I love the simplicity among ingenuity of this. If you've not read it already, you might like http://www.mayofamily.com/RLM/txt_Clarke_Superiority.html

klodolph3• 8 years ago

When assembled precisely, analog computers can be much more accurate than digital computers on these types of questions.

Stopped reading here... whoever wrote the article is missing some critical pieces of the theory of how computers work or what computers are, as well as some basic understanding of how materials work. Mechanical computers are made with parts that have some finite tolerance in their manufacture as well as some measurable amount of flexibility in their parts and connections. Increasing the accuracy of analog computers requires developing new manufacturing techniques to reduce this error. On the other hand, making a digital computer more accurate just requires some extra memory and CPU time.

These analog machines are beautiful computers... but they are not more accurate than digital computers.

pavel_lishin• 8 years ago

Maybe they meant contemporary digital computers?

Although you're right, the claim that

Because they use physical rather than digital inputs and outputs, they can represent curves and other geometric elements of calculations with an infinite level of resolution

is obviously bullshit, although the article does point this out:

(though the precision of those calculations is based on how well their parts are machined, and loss from friction and slippage).

klodolph3• 8 years ago

This is just a really roundabout way of not saying anything at all. "Analog computers can have infinite resolution, except for the fact that this is physically impossible." I could just as easily say, "I am a millionaire, except for the fact that I do not have that much money," or "My house is red, except for the fact that it is actually green, and no part is actually red, and I do not even have a house."

Bjartr• 8 years ago

I did not see any link to the full training video[0] the clips in this article were taken from. I highly recommend it. It's a fascinating trip into engineering, computing, and the past.

[0] https://www.youtube.com/watch?v=s1i-dnAH9Y4

stcredzero• 8 years ago

The XC-142 tilt wing VTOL airplane, basically the 60's version of the V-22 Osprey, used an analog computer to mix the control continuously outputs between vertical wing mode and horizontal. (For example, differential thrust means roll in vertical mode, but yaw in horizontal mode, whereas ailerons go from roll in horizontal mode to yaw in vertical.)

https://en.wikipedia.org/wiki/LTV_XC-142

I am even more impressed by this, having implemented the control mixing for a model XC-142 on a microprocessor.

vmh1928• 8 years ago

Imagine if self-driving cars used an analog mechanical computer such as these. "bicycle bearing one niner zero at 1.5 knots, intercept in .0025 seconds...."

When mechanical analog computers ruled the waves (2014)

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