The Nanomechanical Computer

eldavojohn writes "The BBC is reporting on a newly proposed type of nanomechanical computer that mimics J. H. Müller & Charles Babbage's work on mechanical computational devices — just on a much smaller scale. The paper is published today in the New Journal of Physics and cites three reasons to build a computer with nanomechanical transistors over bipolar-junction or field-effect transistors: '(i) mechanical elements are more robust to electromagnetic shocks than current dynamic random access memory based purely on complimentary metal oxide semiconductor technology, (ii) the power dissipated can be orders of magnitude below CMOS, and (iii) the operating temperature of such an NMC can be an order of magnitude above that of conventional CMOS.'"

You don't need our permission

[QuantumG (50515)]

The paper claims to have shown how to make a nano-mechanical computer using contemporary silicon production facilities. I've gotta wonder, what are you waiting for? Pay the $10,000.. send off your image to be made and test the damn thing.

This is like half science.. "Here's my hypothesis, someone test it for me."

Re:You don't need our permission

[FasterthanaWatch (778779)]

This is like half science..

Must everyone be an experimentalist?

Re:

[heinousjay (683506)]

"Propose to an Englishman any principle, or any instrument, however admirable, and you will observe that the whole effort of the English mind is directed to find a difficulty, a defect, or an impossibility in it. If you speak to him of a machine for peeling a potato, he will pronounce it impossible: if you peel a potato with it before his eyes, he will declare it useless, because it will not slice a pineapple."

- Charles Babbage

Funny that you should mention that

[Moraelin (679338)]

1. Funny that you should mention that, given that Babbage, get this: never actually finished his machine, so he never actually delivered any value for the ample funding money he received. Other people get into the v2.0 syndrome after they completed one successful project. Babbage couldn't be even arsed to finish the first one (although, again, he did receive more than enough funding for it) before he started designing the second version. Then the third. Then the fourth. What is now known collectively as the Analytical Engine is actually a whole series of different machines: he could never be arsed to actually finish building one before he got distracted and started the next one. He kept at it until his death.

His machines _would_ have worked, if they had actually been completed. But he could never be arsed to. Whenever he got funding for one, he'd deliver exactly nothing for that money.

So, you know, maybe _that_ is why Babbage found the Englishmen somewhat reluctant to invest in his designs. Had he actually finished the Differential Engine, maybe people would have been more receptive to his next ideas. Maybe instead of bitching about his fellow Englishmen, it would have been easier to just deliver what he had promised. Just a thought.

And maybe we would have had programmable computers a lot earlier. But as it is, it took people like Konrad Zuse in Germany or Alan Turing and the other folks who built the Colossus computer in the UK, to get it started. Because they actually delivered something that worked. Bloody huge difference there.

2. The complaint about "slicing pineapple" is actually invalid too. Like many nerds today, Babbage was in it just for the fun of researching something new, and apparently thought that people should give him a lot of money just so he can have some nerdy fun.

Capitalism, even the 19'th century kind -- actually, _especially_ the 19'th century kind -- doesn't work that way. To get some funding, the question you must answer is, basically, "which of _my_ problems does this solve?" If that company is in the business of slicing pineapple, then, yes, a machine which peels potatoes is completely useless to them.

Governments too, while they do fund some fundamental research too, have a fiscal responsibility to the citizens they tax for that money. Especially in the 19'th century laissez-faire ideology, when the government was lean, mean, and barely funded to maintain the army. You can't seriously propose a tax hike just so Mr Babbage can play with something cool and high tech. So basically they too have to ask, "ok, so what do _I_ gain from this? Does it compute ballistics for our battleships? Total the census? Or what?"

You'll notice that the working examples that did get computing started, had a satisfactory answer to exactly that. The Colossus computer broke enemy codes for the UK army, and Zuse's machines did aerodynamics calculations for the German airforce. E.g., the Z2 was used to design glide bombs.

Re:

[gnalre (323830)]

Babbage couldn't be even arsed to finish the first one

The reason Babbage had problems completing the project was that it required precision and standardization unparalleled in any previous project. The design and concept was there, the production capabilities lagged severely behind. Even so, one of the offshoots of the project was the development of techniques and procedures for the production and reproduction of standard components, one of the cornerstone of modern mass produced industry.

So even though the computer was never completed, as with other fundamen

Wrong, actually

[Moraelin (679338)]

The reason Babbage had problems completing the project was that it required precision and standardization unparalleled in any previous project. The design and concept was there, the production capabilities lagged severely behind.

Wrong, actually. The machine that was built at the end of the 20'th century was built with the precision and tolerances of the 19'th century. Deliberately, to show that it was possible.

The precision argument is even more obviously false, when you look at the fact that very precise watches had existed for a long time. That's how they measured longitude before GPS. I use watches as an example, because they're cog-based machines too, and they required even higher precision. By the middle of the _18'th_ century (i.e., a century earlier than Babbage) even a pocket watch would already not deviate more than a minute per day, and the second hand gradually became common. (Previously they tended to have only hours and minutes hands.)

The first practical nautical clock, John Harrison's H4 was first used aboard the ship Deptford which set sail for Jamaica on 18 November 1761 and actually arrived there on 19 January 1762. That's two months and a day at sea. After all that time, it was only off by 5.1 seconds.

_That_ is the kind of accuracy that was already available a century before Babbage.

Babbage's design didn't even need that kind of accuracy, since it was essentially a digital device. All that mattered was how many teeth of the cog had moved, not also to do it within a very exact time interval. Half the sources of inaccuracy of a watch, didn't even apply there.

So, no, Babbage had no excuse. The production capabilities were there, the precision was enough, and standardization wasn't even necessary for a prototype. He just couldn't be arsed to actually deliver what he promised. Full stop.

Re:Wrong, actually

[gnalre (323830)]

Wrong, actually. The machine that was built at the end of the 20'th century was built with the precision and tolerances of the 19'th century. Deliberately, to show that it was possible.

There was no doubt that the capabilities to make precision devices were available at the time of Babbage. However these devices were hand crafted, bespoke items. What Babbage machine required was precision designed machinery on an industrial scale(Note the difference engine required 25,000 parts, compare that to the average part count of a watch). That had never been attempted before and could not be achieved within any reasonable timescales using the hand crafted techniques of watchmakers and the like.

However the lesson learned allowed engineers such as Joseph_Clement(http://en.wikipedia.org/wiki/Joseph _Clement [wikipedia.org]) and Joseph Whitworth(http://en.wikipedia.org/wiki/Joseph_Whit worth [wikipedia.org]) to learn the importance of standardization and produce the tools to mass produce precision devices and therefore paving the way to modern industrial production.

Re:Wrong, actually

[Moraelin (679338)]

1. Even if it were so, I'd bet that showing an imperfect prototype would have done a hell of a lot more good than bitching about Englishmen.

Let's say it would have been useless past, dunno, 2 decimals. It would still have been proof of concept.

John Harrison didn't get his nautical watch right in the first try either. There's a reason why the first used version was called "H4". Because H1 to H3 weren't yet accurate enough. And H1 didn't properly compensate for the ship's movement either. But he had _something_ to show to the admiralty, as proof of concept and as proof that indeed it is at least a little more accurate than the average pocket watch one could buy at the nearest watchmaker. It worked wonders to secure more funding for the next version. Although the project was had already overrun the initial money offer and deadline, it showed that _something_ is happening there.

Basically think in terms of iterative software development. It's easier to keep the client happy if he gets _something_ usable often, or at least sees that some progress is made, than if he has to wait for the deus-ex-machina miracle where everything is just perfect at the end of a very very long time. What Babbage did was, more or less, equivalent to not only keeping the client waiting for the first version, but scrapping the design and starting from scratch, again and again and again, to the point where nothing whatsoever was ever ready or usable or even in a demo state.

Well, that sounded maybe too harsh. I'm not (primarily) trying to damn Babbage, but to say _why_ those Englismen that he damns were so skeptical. For all his claims, he worked on it from 1822, when he first presented his proposal and got funding, to his death in 1871 without ever having a version that works even as a crude tech demo. That's a whopping 49 years. You can't really blame anyone for being skeptical if your project was _half_ of that time overdue and still had nothing to show.

Even nowadays most clients would just pull the plug on a project if it was just one year past the deadline, or often less than that. And noone would blame them for it. Even if you had a project of your own funding, you'd be ridiculed long before 49 years passed if it was still going nowhere. We made fun of Duke Nukem Forever when it was overdue a tenth of that time, and also in a tenth of that time Daikatana's hype generated a _very_ nasty backlash. Just, you know, to put things in perspective.

So what I'm saying is: don't take Babbage's bitching as some great insight into the Victorian era England or into the human species as a whole. Babbage's problem wasn't that the English were blockheaded, but simply that he kept hyping a concept and asking for funding without anything to show even as a proof of concept. With or without technical problems, _of_ _course_ the English were skeptical after all that time. That's all.

2. At the risk of repeating myself, the machine built in IIRC 1991 after Babbage's schematics was deliberately built using the tolerances and precision that would have realistically been available in the 19'th century. It worked, and calculated PI with 31 decimals.

Yeah, RTFA

[someone1234 (830754)]

From TFA: "The researchers are currently building the first elements needed for the computer, focusing initially on transistors, the basic switches at the heart of all computers." Insightful? My ass.

Re:You don't need our permission

[CarpetShark (865376)]

what are you waiting for? Pay the $10,000

Perhaps he's waiting for the $10,000, or perhaps he knows that theory is the important thing, and if it's viable, there will be many organisations vying for better and better implementations.

This is like half science.. "Here's my hypothesis, someone test it for me."

I for one don't consider science to be something that only people with money do. One has to wonder how many da Vinci's there would have been, if other people all had the resources he had. The renaissance itself shows that progress pops up everywhere, given resources. Doesn't mean the science wasn't there in the back of people's minds, waiting for them to get past the point of scraping together money for a loaf of bread, though.

Re:

[Futile Rhetoric (1105323)]

I'm with you, man. How dare this lazy asshole release an idea to the scientific community to criticise, or, God forbid, improve upon. Lazy fucking cunt.

Re:You don't need our permission

[QuantumG (50515)]

Dude, this kind of speculative crap is published every 6 months. Going from theory to practice is the science and until they do any they're just masturbating in public.

Re:

[Harmonious Botch (921977)]

And even when they do build one they will be turning their crank in public.

Re:You don't need our permission

[eggnoglatte (1047660)]

Going from theory to practice is the science...

Actually, that would be the engineering. As in "there is no rocket science, there is physics, and then there is rocket engineering". Meanwhile, publishing the initial idea for other people (like, uh, an actual engineer) to built on is very valuable.

Oh, and your premise is wrong: building a MEMS chip of a non-trivial size pretty quickly runs in the hundreds of thousands of $, even with educational discounts. So pretty much you have to get the design ready, then ask for funding to build the thing, which is what they are presumably doing.

No "Diamond Age" in the tagging?

[warrior (15708)]

Neal Stephenson wrote a book about this kind of tech back in 1995 or so, entitled "The Diamond Age" (or "A Young Girl's Primer or something like that). He envisions some pretty incredible stuff made out of this tech. Great book, lots of nerdy CS-type stuff in it. Go to the library and pick it up, very fun stuff. I think this one of his works is very underrated. If we can actually engineer stuff like this it would be impressive, indeed.

Re:

[LordLucless (582312)]

I quite liked that book, except for the ending. The first three quarters were pretty cool, then the main character goes on a bad trip and gets laid, and everything's suddenly alright. His other works are deservedly more well-known in my opinion.

And K. Eric Drexler wrote about it in '85

[maynard (3337)]

See Engines of Creation [e-drexler.com].

order of magnitude?

[by Anonymous Coward]

"Order of magnitude" is a pretty silly phrase to use in this context. From the paper: "The operating temperature can be as high as 500C." So I guess they're using Celsius as the scale, not absolute temperature.

Re:

[by Anonymous Coward]

Yeah it doesn't make sense. In another context if something operates at 50C instead of -50C, would they claim log_10(-1) = i*pi/log(10) orders of magnitude?

Prior art...

[kebes (861706)]

This present design is a cool idea. I don't want to take anything away from the presented concept, but I thought it would be important to point out previous work on nanomechanical computers. First of all, Eric Drexler [wikipedia.org] (the guy who popularized the term "nanotechnology" and who basically invented the field now known as molecular nanotechnology [wikipedia.org]) has been advocating the concept of nanomechanical computers for many years now (they are described in his book Engines of Creation (1986) and detailed feasibility calculations, and rough schematics, are presented in his book Nanosystems (1992)). Drexler has been trying to get people on-board with his very foreward-looking ideas for nanotechnology: where nano-sized mechanical systems would be performing computation, and controlling chemical reactions with a precision that currently only biological systems can achieve. (It should be noted that current work in "nanotechnology" is hilariously primitive compared to what Drexler intended the term to describe.) Drexler's vision of nano-mechanical systems has been challenged by many people, most notably by Richard Smalley [wikipedia.org] (the guy who discovered buckyballs).

Beyond Drexler's theoretical work, carbon nanotubes [wikipedia.org] were demonstrated as nano-mechanical transistors in 2000. Basically, the nanotube was positioned over various electric pads. A current could be applied to mechanically deform the nanotube. The deformation was stable, and could be read-out by measuring current across the tube. Since the deformation was stable and reversible, the tubes could be used as persistent storage or as switching/logic elements. In fact, switching speeds of gigahertz were demonstrated. The vision was to have long nanotubes in a huge cross-bar architecture, leading to high-density persistent storage. As is often the case, scale-up was difficult.

This present work appears to pattern a nano-sized post between conducting pads (out of a gold/silicon layered system) , and to use that post as a single-electron transistor. The 'mechanical' part comes from mechanically coupling multiple pillars to use as a gain mechanism for a transistor. This is basically much closer to conventional micro-lithography, and as such, it should fit in with current lithographic infrastructure much more easily than the nanotube concept did.

Re:Prior art...

[erichill (583191)]

Folks in the nanotech crowd have been talking about clockwork computing from the get-go. Gears and rods and the like have a lot of advantages over electronics at molecular scales: atoms much smaller wavelengths than electrons thereby easier to localize. Also, to a first (and second) approximation, covalent bonds don't wear: undesired reactions are the issue, and not much of one in the mechanical phase of matter(*) envisioned by Drexler and company.
Having skimmed the article, I'm a bit unimpressed by the comparison to Babbage. While this looks like neat technology, it's NOT clockwork--it's electronic transistors with mechanical gates, as noted in the parent.

(*) Parts only touching where desired, vacuum elsewhere--remember, we're talking atomic scale here.

Re:

[C.A. Nony Mouse (860026)]

Look back further still, to Richard Feynman in 1959 [zyvex.com]. Absolutely visionary stuff.

This isn't news.

[mark-t (151149)]

I remember the notion of building Babbage engines at a molecular scale at some point in the future being brought up in an electrical engineering course I took in the mid 1990's, and it probably wasn't a particularly new notion even then. Granted, we're certainly closer to being able to actually do it now than we were in 1996, but it's still not a new idea.

Technological Advancement

[DynaSoar (714234)]

I keep seeing a miniaturized, massively parallel array of Dr. Nims.

http://en.wikipedia.org/wiki/Dr._NIM [wikipedia.org]

Also See the works of Neil Stephenson...

[RyanFenton (230700)]

Specifically, The Diamond Age [wikipedia.org], where such specifically mechanical nanomachines, along with artificial diamond, define the era the book takes place in. I'd say it's a charming if hyper-technical story if you haven't read it - though, things get rather unsafe for some young children in terms of strong sexuality for one prominent subplot.

Anyway, the machines aren't self-replicating, but they are fabricated in microwave-style (and larger) boxes that take an elemental 'feed' of organic compounds and data. The book has some great philosophical and social content, and breaks most of the annoying characteristics of the previous 'cyberpunk'-style writing.

Ryan Fenton

Re:

[Prof.Phreak (584152)]

It's also very long... and keeps going on and on, way past the point it should've ended...and then it ends suddenly and for no apparent reason.

That was the only Stephenson book I really got bored off...

Re:

[tftp (111690)]

Some books end abruptly when the writer reached the word count that he promised to the publisher.

Re:

[simong (32944)]

I thought that the first time I read it, but then I read it again a couple of years ago and realised that he got a bit stuck in trying to resolve his different strands of story and had to finish a couple of them a bit abruptly. Then again he did the same with Cryptomnicon, and as far as I can see hasn't managed to finish the Baroque cycle at all (joke).

One thing though...

[Viceroy Potatohead (954845)]

It may be a more robust transistor when dealing with shocks or heat, but I wonder if the same claim can be made for material wear. They'd be some diamond-like carbon structure, sure, but do we really know how robust those would be under such conditions (billions of jitters/sec rubbing against other pieces)? It could cause part wear or moving of parts, I would think....

Still, good on 'em....

Re:One thing though...

[wall0159 (881759)]

I'm not a nano-technologist, but I'd doubt that macroscopic ideas of friction and wear would apply to nano-machines.

Man Proposes, Mechanics Disposes

[Doc Ruby (173196)]

They're far from the first to propose nanomechanical computing machines like Babbage's original (and failed) machines. A mentor of mine explained to me in 1990 an idea of building nanoscale rod logic [wikipedia.org] in orbit: microgravity, vacuum, solar power. And I don't think he was the first to think of it.

I'll be impressed when someone actually builds some. Or writes a lot more engaging science fiction than the BBC just published.

Nanotech science

[the_kanzure (1100087)]

From my collection [heybryan.org]:
* Nanotechnology information [archive.org] [archived] [2002]
* Bibliography of nanotechnology and nanoscience [tu-darmstadt.de] [pdf] [2004]
* Brad Hein's nanotechnology website [nanosite.net]
* Ned Seeman's DNA nanotech bibliography [nyu.edu]
* MEMS/nanotech reading list [mems-exchange.org]
* Even more publications in nanotechnology [dyndns.org]
* sci.nano archives [leitl.org]
* The open micro/nano-manufacturing project [uky.edu]
* Nanotech in scifi [geocities.com]

And if anybody has links on nanomechanical synthesis, that'd be much appreciated. IIRC, nanolithography is one of the main areas of development, along with nonlinear optics to get the required precision manufacturing.

Shock and vibration

[flyingfsck (986395)]

If the Nikei stock exchange uses a mechanical computer, then an earthquake in Japan will really send a shudder through the financial markets...

Re:

[evanbd (210358)]

Hardly more so than they are now -- the damage would be physical damage to the computers, just like it is now. Vibrations on the scale of Hz to tens of Hz won't impact a mechanical computer operating at many GHz any more than your car is affected by the "vibrations" caused by going up and down hills.

Fallout games - cathode tube computers

[Zantetsuken (935350)]

Well, I guess the retro-futuristic cathode tube computers in the Fallout series will be trumped by an even more retro-ish mechanical processing power...

I, for one,

[Tu-Ply (1132719)]

welcome our Nanomechanical overlords...

It's not new

[Eivind (15695)]

It's an interesting concept, but it is not in any way a "new" concept. It was, for example, explored in Drexlers "Engines of Creation" that is (in full) available online under http://www.e-drexler.com/ [e-drexler.com] EOC was first published in 1986, so the idea is more than 20 years old.

Don't think Babbage, think relay computers

[Flying pig (925874)]

I don't think they are actually postulating something like a Difference Engine at all. The reason? I/O. With the exception of piezo inkjets, that market has gravitated to thermal drive for the ink and all the upcoming inkjet designs I know of also use electrical power->heat to drive the ink. The article talks about engine management systems, but again the I/O of these is currently electrical, driving motors and solenoids, and given the sheer amount of development invested in the present technology, the timescale to invent cheap and reliable mechanical amplifiers will probably mean that the I/C engine will be more or less obsolete before it happens.

I suspect that what is being thought of is actually relay technology - so let's call it a Turing/Von Neumann/Mauchly approach (Alan Turing was a pioneer of relay logic among his other achievements, and Von Neumann and Mauchly were both associated with relay calculators.) Although relay computers were effectively obsolete by the 70s, they persisted in industrial controls for longer because (a) they could be debugged by electricians and (b) they could tolerate levels of contamination that destroyed the electronics of the period. The last generation of ultra-clean sealed relays and mercury relays were extremely durable and reliable. They didn't have the power handling, size for size, of power transistors but they had less internal dissipation. As a simple example, I was designing equipment in the late 80s which had to switch a few watts at around 500VDC. Although there are transistors that can handle these voltages, the design of the switching circuit necessitated a hybrid device costing around $200. A suitable relay cost $10 and was immune from punchthrough.

I'm prepared to guess that there will be niche applications for these ideas - but as with the IC engine, the sheer accumulated R&D in electromechanical systems will mean that widespread adoption will never be economic. It's easier to duct cold air over an engine management system (as on my car, with a few $ of plastics) than it is to redesign the entire chain from logic to actuator to use a different technology. And the current density of flash memory suggests that the hill to be scaled by electromechanical memory is enormous. Back in the days when flash chips were 256 bytes and not too reliable, there might have been a chance. Now when 8GByte USB dongles are cheap and reliable, it will be a lot harder.

Re:

[Bottlemaster (449635)]

I'm prepared to guess that there will be niche applications for these ideas - but as with the IC engine, the sheer accumulated R&D in electromechanical systems will mean that widespread adoption will never be economic.

I'm guessing that your guess is correct, but widespread adoption isn't everything. Niche markets are almost always (relatively) expensive markets, and that leaves more room for profit than a commodity market does. There is a healthy market for extremely reliable, low-power electronics, a

Don't disagree

[Flying pig (925874)]

I'm just very tired of mass media overhyping engineering that may have almost no effect on most people. It leads to cynicism of the "what happened to my flying car" variety.

Re:

[Arimus (198136)]

Given the average ability of people to move their car correctly in two dimensions I, for one, am glad that flying cars are still not available...

Technology of the past getting new life

[bitrex (859228)]

The research presented in this article reminds me of a an abstract I read a while back about a team who developed an on chip vacuum tube micro-triode which used carbon nanotubes as field emitters. It might not be possible to build a computer out of them, but logic built from them would have some of the same advantages mentioned in TFA (high immunity to electromagnetic radiation, etc.)
Link (warning PDF) http://ieeexplore.ieee.org/Xplore/login.jsp?url=/i el5/16/21940/01019936.pdf [ieee.org]

Sure, it resists electromagnetic shocks

[m50d (797211)]

But aren't mechanical shocks more common for your typical computer? And won't these machines take far more damage from them than current solid-state ram?

Ridiculous idea

[Ancient_Hacker (751168)]

Like, totally ridiculous idea:

• Moving parts do not scale down at all! Even at the micro-meter level, effects like friction, surface tension, dust, and gas make moving parts impractical to impossible. Even in a good vacuum there are too many gas molecules to make nano-scale mechanics work.
• Your typical moving parts are good for maybe ten million operations before they wear out. Figure out how long your computer would last at that rate.
• Error and assembly error rates for mechanical devices are much too hi

Reversible Computing?

[martyb (196687)]

I know this is /. and actually reading the article [iop.org] is unusual, but *I* did and came upon this:

A computing architecture made from nanomechanical transistors thus is competitive with 45 nm CMOS technology Note 2, while taking a step towards enabling reversible computing. (emphasis added)

I would LOVE to see THAT happen!

<dream>Whenever a program crashes, just open the debugger, run it backwards until it gets "weird". Run it forwards and backwards again to isolate where it's broken. Of course, there are some problems with asynchronous signals (disk I/O, keyboard, mouse, etc.) but I can dream, can't I?</dream>

But seriously, could this just be something thrown in to help get more funding or is it an actual possibility?

Re:

[marcosdumay (620877)]

You should take a look on the meaning of "reversible computing" [wikipedia.org].

In short, you won't be able to reverse all operations on a debuger, but it may save some money at your light bill. Personaly, I can't see how it can be used, but I'm no expert on it, and there is a lot of buzz on that.

A tuning fork in a convential chip

[mattr (78516)]

If I interpret TFA and its references (which are more useful even just as abstracts) correctly, this is not at all the "rod logic" of Stephenson/Babbage fame. It is a single transistor, built out of two metal terminals (source and drain) and a tall, thin pillar standing between them which vibrates like a tuning fork (at 300MHz - 1GHz or so).

This pillar can be charged from the terminals and by transferring charge it can switch the current. This nano-electromechanical single electron transistor (NEMSET) was invented by other researchers, TFA mainly explores electronic properties of the NEMSET and how to put them together into circuits, create circuit elements, etc. but they didn't really do any of it yet.

Mainly it can run at high temperatures, is not as fast as ordinary transistors, but seems like it could offer multivalued logic not just binary, and as for power just about anything will do, including self-excitation, environmental vibration, etc.

So while this might be just the thing for making a laptop you can use without frying your gonads, it is not what one might think when hearing the words "nanomechanical computer".

Re:

[RuBLed (995686)]

I now have a string of unfinished projects to my name that certainly eclipses what Babbage did.

You must be renting a warehouse or something, I'm having trouble fitting a difference engine in our basement..

Re:

[macraig (621737)]

Nah, I have a buddy who owns an auto junkyard, so I get 'em half finished and then throw 'em in the car crusher. They come out small enough to fit under the bed.

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[ducman (107063)]

The point is that it's NOT at equal switching speeds. If you have an application for a computer that doesn't need to switch very often, but does need to be extremely reliable, this might help.