Hydraulic Analog Computer From 1949

mbone writes "In the New York Times, there is an interesting story about a hydraulic analog computer from 1949 used to model the feedback loops in the economy. According to the article, 'copies of the 'Moniac,' as it became known in the United States, were built and sold to Harvard, Cambridge, Oxford, Ford Motor Company and the Central Bank of Guatemala, among others.' There is a cool video of the computer in operation at Cambridge University. I remember that the Instrumentation Lab at MIT still had an analog computer in its computer center in the mid-1970s. Even then, it seemed archaic, and now this form of computation is largely forgotten. With 14 machines built, it must have been one of the more successful analog computers — a supercomputer of its day. Of course, you have to wonder if it could have been used to predict our current economic difficulties."

Comments

Explosives factories

[flyingfsck]

Some explosives factories still use hydraulics, steam or vacuum for process control. Although it tends to be digital now, with valves used as flip-flops.

Re:Explosives factories

[Keruo]

Upgrade properly to what? Hydraulics is the most accurate way to control movement.
If your application needs force with direction and accuracy, then your only real choice is to use hydraulics.

Don't confuse modern hydraulic systems with something that just has few handvalves.
Almost every system we deliver these days comes equipped with computer controlled digital valves which you can use to control pressures at 0.01 scale from 0 to 500+ bar(depending on customer specs naturally), and can be integrated into factory networks seamlessly.

[disclaimer, I have bias on this subject since I work at one of the largest suppliers of hydraulic systems in the world]

Re:Explosives factories

[Sen.NullProcPntr]

There is what could be described as a hydraulic computer that people use everyday;
The automatic transmission. Granted it has a fixed program but the early ones did use nothing but transmission fluid.

Wierd! Just read Terry Pratchett's

[bareman]

I just finished with Terry Pratchett's "Making Money". I think I'm having a flashback now.

Used in fighter planes

[Maximum Prophet]

Hydraulic computers are used in some military aircraft because they are very reliable and can withstand EMP.

Re:Computers can't model macroeconomics

[OwnedByTwoCats]

There are some fundamental limits to what models can predict. If a model demonstrates extreme sensitivity to initial conditions, then any deviation between actual and measured initial conditions will cause the output of the model to deviate from actual at an exponential rate.

Not quite

[DerekLyons]

With 14 machines built, it must have been one of the more successful analog computers

 
In the early 80's the USN had over 30 analog computers driving various submarine simulators. Heck, each of the original '41 SSBN's had an analog computer driving the hovering system. Then there was the 100+ analog installations of the CONALOG system.
 
Etc... Etc...

Re:Not quite

[Nimey]

Also the famous Norden Bombsight, the most accurate in the world at the time, was an analog computer.

Re:Wierd! Just read Terry Pratchett's

[TheRaven64]

And this is why you should always read the author's note at the end, where he mentions all of the things that he based inventions in the book on. You also get fun things like, in the end of Nation, an explanation of thinking, followed by 'do try this at home'

Re:Computers can't model macroeconomics

[wjwlsn]

Your post reminds me of a quote from Gordon Box that I often relate to new trainees: "All models are wrong, but some are useful."

I don't think this modeling difficulty is unique to economics. (You didn't state or imply that it was... I just wanted an excuse to quote Gordon Box.)

I like your characterization of the problem though. It applies to pretty much any complex system.

Other Great Analogue Computers

[Nom du Keyboard]

What about The Great Brass Brain? An analogue computer for computing tide tables that when replaced by a CDC 6600 super (for its time) computer, the 6600 couldn't perform all of the tricks (i.e. pause at each low/high tide moment or produce a continuous) graph of the machine it replaced? There's some great, mostly lost, history out there.

Another resource too...

[DrYak]

The Annotated Pratchett File has also interesting resources to help grasp to more obscure jokes.

horrible video

[Teque5]

'cool video' is really a misnomer - the guy doesn't explain anything and nothing happens. 3:28 of my life i will never get back.