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

[Thanshin]

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.

Furthermore, the factory itself can be considered as a digital information storage system.

The problem is returning to the current state after it flips to the other one.

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

[K. S. Kyosuke]

Don't be shy to say it, a factory is a 1-bit PROM. Perhaps one day, a socially challenged but otherwise very friendly hacker will try to become immortal by writing "HELLO WORLD" into such memory, but no one will understand him, as usual. :-(

Re:Explosives factories

[petermgreen]

Indeed, when it comes to anything safety crtical KISS is a good principle to follow as it will make it much easier to ensure safety.

Computers can't model macroeconomics

[MSTCrow5429]

There is a serious flaw in thinking that computers can accurately model macroeconomics, or predict systematic collapses, any better than commonsense and basic logic can. It is a given that if you massively inflate the monetary supply, you will create a false sense of wealth and a false understanding of risk, and people will malinvest in sectors that they otherwise would have spent far less resources on, or none at all. This is an unsustainable artificially created bubble, and all bubbles burst. Many people saw this coming years, even decades ago, and didn't have supercomputers. People understood this scenario centuries ago, before computers even existed. Using computers as a crutch to make up for a lack of understanding of basic economics is an aggravating factor in the current scenario, not the solution.

Re:Computers can't model macroeconomics

[caffeinemessiah]

There is a serious flaw in thinking that computers can accurately model macroeconomics, or predict systematic collapses, any better than commonsense and basic logic can

It might not be an accurate descriptive model (one that describes reality), but discriminative models are very useful -- not to predict systematic collapses, but to discriminate irrational behavior. Computers step in when your response time has to beat efficient markets. You could be a common sense and logic genius, but you can only apply those rules and react in so much time, and computers will always beat you for speed at applying your own rules. So it's a different kind of crutch, and just like a crutch, it can help you walk better, not walk for you.

I might have digressed from TFA, but this is /.

Re:Computers can't model macroeconomics

[vertinox]

There is a serious flaw in thinking that computers can accurately model macroeconomics, or predict systematic collapses, any better than commonsense and basic logic can.

Are you saying that human irrationality is defined by something other than the laws of physics, genetics, and chemistry?

If we are to believe that the universe does have a set of laws applied to it, then by understanding those rules can lead to models that will predict otherwise seemly irrational universe.

You just have to have the right model and a computer powerful enough to compute all the date required to get something use.

And you have to sometimes build something as big as the LHC to figure what model you should use.

To assume that this cannot assumes that universe does not have rational rules and is ruled by something else like a supernatural force.

Like you know... Like a Flying Spaghetti Monster?

Re:Computers can't model macroeconomics

[fiannaFailMan]

Spot on. I saw this mechanical computer on TV years ago, they were talking about how it was a noble attempt to model the economy but it's just too complicated an organism to be modelled by any means, to say nothing of a mechanical device. Sometimes the economy reacts differently when you poke it the same way depending on a myriad of other factors.

Another example is traffic. Some people assume that traffic can be modelled like water in pipes. "Road is congested? Make it wider and the congestion will ease." What they don't realise is that motorists are more intelligent than water particles. They can be aware of a widening of the pipes/roads and choose to go into a system at a certain point at a certain time to take advantage of the widened road, with the net result of a road that's just as congested at 4 lanes wide as it was at 3 lanes wide. There's also the matter of being able to move one's home to a different location along the road to avoid congestion. Others follow suit, and the congestion is back to where it was. Want to model that using water in pipes? Good luck!

Re:Computers can't model macroeconomics

[Trepidity]

I think it's not so much that it can't in theory be modeled, as that in practice it's extremely hard---much harder than modeling the weather, which we can barely do accurately out to 5 days. There's somewhat of a gap in expectations when you go from high-level qualitative descriptions of phenomena, like hurricane experts discussing trends in intensity and formation basins, to an implemented, detailed computational model that purports to simulate what "really" happens. The 2nd one usually diverges extremely quickly from what actually does happen, because these sorts of nonlinear systems are very sensitive to slight errors in the model or its initial conditions.

That's fine, as long as people understand its use and limitations; but there's a tendency, especially among the only-sort-of-technical folks who are involved in a lot of areas of business and economic policy, to trust these computer models as more than they are, as if the fact that a "computer simulation" told you it makes it some sort of neutral third-party truth that represents the state-of-the-art in guessing what will happen.

Re:Computers can't model macroeconomics

[fastest fascist]

It doesn't take a computer to predict what happens. You get a boom, people spend money, they overspend, you get a crash. Repeat. The details vary, but the basic pattern seems pretty clear.

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.

Re:Computers can't model macroeconomics

[TheRaven64]

Modelling the economy is more difficult than most other modelling tasks because everyone is trying to do it. Every single actor in the system has their own model, of varying quality, which governs how they interact with it. When you build a better model of the economy, you have an advantage over the other players and so can make more money, which alters the economy. An accurate model which no one acts on is possible, but an accurate and useful model needs to be sufficiently complex to model itself and all of the other players. Or, to put it another way, needs to be more complex than itself. That's not to say that you can't build a partially-accurate and still useful model, of course.

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.

Re:Computers can't model macroeconomics

[Tokolosh]

All you need is the Micawber Principle:

"Annual income twenty pounds, annual expenditure nineteen pounds nineteen and six, result happiness. Annual income twenty pounds, annual expenditure twenty pounds ought and six, result misery."

From David Copperfield, by Charles Dickens

Re:Computers can't model macroeconomics

[zindorsky]

What they don't realise is that motorists are more intelligent than water particles.

Says you.

Re:Computers can't model macroeconomics

[JesseMcDonald]

It's worse than that, actually. Weather prediction is at least based on physical processes, which, allowing for some minor concessions to quantum mechanics, are based on fundamental particles which follow deterministic rules. Given all the initial conditions and sufficient computing power you could accurately simulate what the weather will be at any point in the future. Moreover, you can use simulations to predict how that future weather will change in response to deliberate artificial influences; weather doesn't have goals of its own, and won't actively resist attempts to control it.

Economics isn't like that. The "fundamental particle" of economics is people, and people are adaptive. Under many conditions is it possible to predict how they will behave--assuming rational self-interest (i.e. sanity) and decent psychological models of their personal value scales--but all that breaks down when someone attempts to use the models to control the outcome. At that point you have a competition between the people being studied, who seek to achieve their original goals and thwart any attempt at outside control, and those seeking to do the controlling. As with any long-running competition between creative individuals, the outcome is impossible to predict with any degree of accuracy.

Perhaps it used the wrong working fluid

[OolimPhon]

It might have been more successful if they had used beer instead of water...

Hot and cold running money!

[thewiz]

Wow! Great article about it in Wikipedia. Loved the picture that showed the two faucets on the side.

Gack... troll in summary... must resist...

[Red Flayer]

Dammit. Couldn't resist.

Of course, you have to wonder if it could have been used to predict our current economic difficulties.

No, you don't have to wonder that. The current economic difficulties were easily predicted by many.

The problem was that the people with any kind of ability to stop the conditions that led to the current situation were those who profited most from those conditions. Not a good recipe for prevention.

Blowing a circuit - with air

[diodeus]

In college I built a divide-by-eight counter in pneumatics. One reciprocating cylinder was the "clock" signal, the rest was a bunch of pneumatic shuttle valves. Problems arose because I kept needing to increase the air pressure to move some of the switches because they were spring-loaded. The air hoses started to pop off their fasteners so it took a lot longer to get the assembly working that I had anticipated (talk about blowing a circuit). It did manage to get me an exemption from the rest of the labs though.

A funnel can model "current economic difficulties"

[shadowofwind]

If lots of people are extracting money from the system and not contributing real wealth, then there will be problems. Money has complicated dynamics, but its not magic. People who make a living shuffling numbers around in spreadsheets are providing a useful service that makes the system more efficient. But only up to a point. Few people believe greed is a vice anymore, hence certain results follow.

Used in fighter planes

[Maximum Prophet]

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

Memory Leak

[SubjectiveObjection]

"Johnny, there's another damn memory leak! Bring the bucket!"

If we would have stayed with this technology...

[sootman]

... the Internet truly would be a series of tubes.

Also, little known fact: Gordon Moore's father was a mechanical engineer who predicted that the size of hydraulic valves would shrink 50% every 18 months.

pneumatic computers exist too

[OrangeTide]

In class I built a half-adder and a full-adder and could do 2 bit addition with it. subtraction too if I interpret input and output as 2s complement numbers. I ran out of parts in my kit to make it bigger. but with enough parts you could do pretty much anything, as long as you don't mind the slowness and noise and possibly a tremendous amount of power.

hydraulics have the advantage that you can apply a great deal of force through them precisely. which is useful when you have many layers of "logic gates" that you have to drive by pushing a fluid through some tubes. with pneumatics I could have quickly ran into an issue if I made a ripple counter for example where the amount of pressure necessary to switch the furthest most element might exceed the abilities of my pump.

Hydraulic Computers

[thethibs]

Which gave rise to one of the oldest computer jokes: "If it doesn't work, piss on it."

Trend setting

[DrugCheese]

This was water cooled before water cooling was cool

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: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'

Yep

[madnis]

Shows that our economy is down the drain.

Re:Discworld anyone!

[SteveAstro]

You'll actually see TP give due acknowledgement to the Phillips Economic computer, Moniac, at the front of the book.

As a result of reading Making Money, I tracked down the prototype, which is in the foyer of the school of management at Leeds University in the UK, and now have the job of rebuilding Phillips very first machine.

Steve

Re:Predict the economic trouble today?

[inviolet]

Probably not, but Byron Dorgon Predicted this trouble in 1995 when teh derivatives markets starte to get noticed and again in 1998 when the "securities modernization act" was passed, deregulating the banks, insurance companies and investments firms.

As we say in Economics circles: "Yes, the man is a genius: he predicted 9 of the last 3 recessions!"

I Once Had a Toy...

[Nom du Keyboard]

I once had a wonderful, yet frustrating, toy whose name I can't remember any longer that was kind of a hydraulic Erector Set. It came with battery-powered pumps, clear plastic tubing, splitting/combining Y and T connectors, valves, tanks, items that filled and then tipped out, a board and supports to arrange everything, and even coloring tablets (messy) to allow blending different streams -- just add water. The frustration came from the poor level of construction that resulted in it not being all that durable and the pumps not seeming to work as long or as well as I felt they should. And when you used it you pretty much ended up with water, and staining colors when you added them, in a mess all around. Even so it was one of the great fun toys (along with Lincoln Logs, Tinker Toys, Erector Sets, and Flexigons) that I would happily play with now if I could find them again. No, we weren't a Leggo family.

obvious...

[FalloP]

now i truly understand a buffer overflow, and the implications of a memory leak are clear.

biennale

[spud603]

I saw one of these in operation at the Venice Biennale in 2003. It was really remarkable to watch, but then I was thinking of it as more of an art project pointing out the absurd nature of economic forecasting than a serious research tool.

Analog computing has its place

[mcrbids]

Often, digital computing is clumsy, awkward, and overly precise.

A good example of this is in Aviation. Pilots are still trained to use the E6B Flight computer which is really a glorified slide rule.

When you are estimating fuel consumption, and figure you'll probably use about 11.5 GPH for 3 1/3 hours, it's not important to know any more accuracy than perhaps to a gallon or so, since reality will always be a bit different than your calculations, anyway. You don't need to be exactly precise on your degrees of heading, and when you are computing weight & balance, it's stupid to calculate your moment to the 4th decimal place.

Knowing how to use an E6B, you can get calculations in a second or two with a single hand that are "good enough" - and that's important when you're flying an airplane in turbulence while trying to stay on top of busy ATC calls in a heavily trafficked area. You can't even enter the first of 3 or 4 digits into a digital calculator in that time, and you'd have to use two hands. (Frequently, when flying, your hands are both occupied and you're steering with just your feet)

Digital isn't always better.

Biased? hardly

[Runaway1956]

I work with and service a lot of hydraulic machines. Generations of them, in fact. The pilot valves and such really haven't changed much in 50 years, as they are a simple device - but the CONTROLLERS are simply awesome. We use mostly David Bradley stuff, but there are plenty of Japanese, Chinese, and Korean valves and controllers in the plant. Amazing how accurate they can be when remotely controlled by a computer. Hydraulically powered computer can be sent 30 feet away from you, and come back, kiss your forehead, or a baby's cheek, and sent out again. It will repeat ad nauseum, and NEVER strike you hard.

Air? I would never trust air powered mechanisms to touch a baby, and simple electric motors can scare me too. Don't even dream of doing it with some kind of gasoline powered machine. Hydraulics are more reliable than anything I can think of.

Crunchly's hydraulic computer

[dido]

There's a whole series in the Crunchly cartoons by Guy L. Steele, such as this one where he buys a hydraulic computer of sorts...