back to article Babbage's Difference Engine hits Silicon Valley

Silicon Valley got its first look at the true roots of the digital age this week, with the arrival of a five-ton calculator made from the designs of the Victorian-age mathematician and Londoner, Charles Babbage. The Computer History Museum in Mountain View, California is hosting the second replica of Babbage's Difference …


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  1. Anonymous Coward

    Difference Engine? Pah!

    Where's my Analytical Engine?!

  2. Herby

    Need modern example to compare against

    What is needed is the something that does the same thing, expressed in modern terms. The problem with that is it might take just as long to build under Windows, and will probably have bugs and/or a virus.

    Hats off the the original designer!

  3. Anonymous Coward

    Ye Olde Box?

    I love this series!

    Seriously though, how much did it cost, and how long did it take to build one? I'd think building a 2nd copy would be much easier & cheaper than the first. And where the heck is an MPEG of somebody cranking away?

  4. Juan Llodra
    Paris Hilton

    "On the shoulders of Giants" and great Architects.

    Newton aside, I recall reading about Gaudi making similar observations about his Sagrada Familia in Barcelona. He reckoned there could be over one hundred years of additional work beyond his time, by many different architects, before his original idea was completed. He allowed for this, opening up his plans and inviting new contributions. Charles Babbage and Antoni Gaudi would have become good mates... (Only included their surnames as a concession to the less educated and Google unaware masses.)

    Paris because she will half-smile whatever you say to her and she'd never question this thread, right? Right?...

  5. josh
    Thumb Up

    saw this being built

    the london science museum made a massive thing about this being built, it really is a mechanical marvel...and arguably a tecnical marvel however it does seem a bit extreme, no matter how much money you have to commission one... its like paying 5 billion for a commodore 64 really isnt it?

    still imagine the size of the house this will fit in!

  6. Anonymous Coward
    Anonymous Coward

    There ought to be more such replicas

    "it does seem a bit extreme, no matter how much money you have to commission one"

    I disagree. In this age of mediocrity, we need more inspiration from people such as Babbage so that future generations might again aspire to proper preparation and planning before doing, versus hacking away without any plan as is the way of our time.

    The common wisdom almost all software developers subscribe to these days is that software cannot possibly be bug free so one might as well not bother to even try keeping bugs out of the design, one should instead get one's work completed first and then remove the errors over time. This mentality has since spread into other areas of technology as well.

    This is in total contrast to how people in earlier times worked. They felt that it was worth while trying to come up with a perfect design and then execute as close to the ideal as possible. Back then, there was absolutely no appreciation for our modern notion of "fix it later". Anybody who would have shown a "fix it later" attitude was automatically identified as a charlatan.

    The work of Babbage, and by extension replicas of the machines he designed are a reminder to us what we can achieve if only we put our minds to it. Therefore, I say, one replica of a Babbage machine in a museum where it can inspire future generations of engineers and scientists is likely to do more good than a million copies of Windows donated for education.

  7. The Wanderer

    Bah, that's nothing

    When I worked for the Register, we had to crank out SIX polynomials PER second, AND they had to be to the NINTH order!! And that was on a machine made of rusted slag and splintered wood!! And when one of the gears slipped... let's just say we experienced a different understanding of the phrase "number crunching"...

    ...and you don't want to know how sore our wrists got after all that hand cranking....

    Absolutely love it!

    Mine's the one with the coal in the pockets for my steam-powered calculator.

  8. Tony

    19th century engineering

    When they building the device, there were a number of articles that made the comment that 19th century engineering couldn't produce the device - not true. There were numerous examples of other devices that were created to the same or better levels of tolerances. the manufacturing processes of the day were more than capable of building it.

    The main problem was the government of the day; my understanding is that they originally offered money to develop the device, then changed their minds about what they wanted it to do. After modifying the designs, they then changed their minds again, and again and........ eventually, they just withdrew the funding.

    Plus ca change?

  9. Flocke Kroes Silver badge

    Beat this Lego photographing vultures...

  10. Chris Miller
    Thumb Up

    I'm sure many ElReg readers will be familiar with

    "The Difference Engine" by William Gibson & Bruce Sterling - an 'alternative history' novel in which steam-powered analytic engines take the place of our electronic computers (and what happens when they experience the first virus ...)

  11. LaeMi Qian
    Thumb Up

    No one-handed web surfing here, I guess

    It is the CPU that needs the hand-cranking rather than the user.


    I want one ;-)

    ... In my cubicle at work!

    ... Just to freak out the MCSEs because it won't run their OS :-P

  12. dodge
    Thumb Up

    Wanna MPEG?

    It really is rather impressive

  13. Paul

    If he had built it...

    I wonder how long it would have taken for someone to work out how to use it for P0rnz?

    Very cool though.

  14. Iain
    IT Angle

    Runs Doom

    I bet SP3 would still break it. Oh, wait a minute, maybe that is what SP3 was tested on! (Note owner)

  15. HFoster
    Thumb Up


    I wrote an essay about Babbage in the first year of my aborted attempt at an Engineering degree, and managed to shoehorn in Ken MacLeod's references to futuristic mechanical computers based on Analytical and Difference Engines.

  16. leslie

    One per desk..........

    That thing is stupidly huge, I know they went from the plans but surely they could have built it half or quarter sized with modern materials.

    How long now before somewhere in china see's these as popular and builds them keyring sized for a $

    I hope they do, I'd have one lol

  17. Andy


    I really don't see what the fuss is about.

    This isn't a computer: it is not programmable, in any meaningful sense of the word.

    A Jacard Loom would be more historically interesting in IT terms. But of course they built quite a few of those...

  18. Anonymous Coward
    Paris Hilton


    "The main problem was the government of the day; my understanding is that they originally offered money to develop the device, then changed their minds about what they wanted it to do."

    If only Charles Babbage had stressed the military applications of his machine, or future designs based on his machine. The Royal Navy would have loved a device that could churn out ballistic tables, and they had the budget and clout for it as well. If not in 1871 then a few years later. I envisage HMS Dreadnought with an enormously complicated automatic computerised fire control system that would presumably break all the time, but imagine if it had worked! Probably not a great thought if you're one of those sentimental hippie types. Babbage missed a trick there.

  19. Paul McConkey

    @ Bothered

    Of course it's a computer. Go and watch the video:

    Apart from the configuration settings for print out, etc. you can actually see the program working - those levers all clicking round in sequence looks just like a recursive loop to me, just because it is programmed in brass, not C doesn't mean it ain't programmable!

  20. Anonymous Coward
    Anonymous Coward


    This is just brilliant. I love it. Babbage, Brunel and several other genial engineers and scientists continue to amaze today, especially taking into account the basic technology that was available back then, and that some of the work was done with calculations, measurements, and staking their reputations on their work.

    My hat off to Charles Babbage.

  21. Tony

    @ Ashley

    "If only Charles Babbage had stressed the military applications of his machine"

    I believe he did - the plan was to produce exactly the types of tables for use by Army & Naval artillery that you suggested. I can't remember what the reason given was, but apparantly, the LOTA decided it wasn't for them.

    I note that by the early 1900's when the Dreadnoughts were being built, Jackie Fisher, then First Sea Lord was appalled by the performance of naval gunnery - less than 10% accuracy. A hundred years earlier, the 32 pounder (firing round shot from an unrifled barrel) could hit a 3 yard target at a distance of 3 miles 90% of the time.

    If I'm not mistaken, the original plan for the colossii built at Bletchly Park were to produce similar tables - that was also rejected by the military.

    As I say, plus ca change.

  22. HFoster

    Nobody has mentioned

    That part of what scuppered Babbage's plans was that he was a miserable old git. He regularly fell out with workmen, and complained about street performers making too much noise for him to concentrate. The former is part of what kept the DE from being built, the latter led to laws about playing music in the street. Next time you see a busker getting a ticking off from the plod, spare a thought for Charles Babbage and the organ grinders that plagued him.

  23. Michael H.F. Wilkinson Silver badge

    Re: N-squared

    HMS Dreadnought actually had an analog computer to do the gunnery maths: look for Dreyer equipment or Dumaresq analog computer,

  24. Andy Davies

    Royal Navy would have loved a device that could churn out ...

    Ah! - but I'm old enough to remember the RN de-commissioning a device that must have been inspired by Babbage (analytical probably) - it was used for calculating tide tables, and was replaced in the 1960's with the biggest offering available from Big Blue, except that it wasn't quite as accurate. The analog device had been running since the mid to late 19th century and had been upgraded once in the 1930's when the hand crank was replaced by an electric motor.

    AndyD 8-)#

  25. DZ-Jay

    Beautiful indeed!

    The CRAY I has just been bumped down from my list of favorite computers ever, as I get swept off my feet by the mechanical beauty of this contraption. Fascinating!

    The original steam punk indeed. Charles Babbage was a genius and an artist.


  26. Anonymous Coward
    Anonymous Coward


    If I understand _Passages from the Life of a Philosopher_ correctly, difference engines built based on description of Babbage's plans were completed. One built by a Swede ended up at the Dudley Observatory in Albany, NY; a copy of this machine was used at the Registrar General's office in London.

    @HFoster: Babbage certainly was an early & ardent perpetrator of scope creep. And his battles with street musicians make for interesting reading.

    @Tony: I wonder about your numbers for 32-pounder accuracy for the early 1800s. Most of the butchery seemed to be done at very close quarters.

  27. A J Stiles

    Set the tone

    It went riduculously over budget and was delivered late. So, it pretty much set the tone for every public sector IT project since .....

  28. Jonathan Richards

    @Tony - gunnery accuracy

    <quote>A hundred years earlier, the 32 pounder (firing round shot from an unrifled barrel) could hit a 3 yard target at a distance of 3 miles 90% of the time</quote>

    That sounds wrong; I call for a URL. 3 yards in 3 miles is clearly one part in 1,760 which would have to be the combined precision of the mass of the shot and the impulse from the cartridge, even without atmospheric disturbance. I don't think even a shore battery could have got the target accuracy you quote.

  29. Kurt Guntheroth

    uninspired machinists

    My understanding was the Royal Navy wanted machine-perfect trig tables for navigation, as there are several clusters of wrecks partially attributable to faulty tables. Babbage had a hand in not getting the thing built, doing a bait-and-switch on his even-more-ambitious analytical engine. It was a classic defense procurement fustercluck.

    Is anyone else dissappointed by the raw 21st century austerity of the replica? In the 19th century, the gears would have been cast, with elegant spokes and a pebble finish, machined only on the working surfaces. It would have *looked* victorian. In replicating the function, I think the fabricators missed out on replicating the feeling of the piece. The replica looks big and fiddly, but it isn't *pretty*, as it probably would have been.

    The whole thing's a metaphor. A microsoft exec wants the thing enough to pay a million dollars for it, and wants it in his living room, and it works, but it's got no soul. Sigh.

  30. Brian
    Thumb Down


    will probably apply for a retrospective patent / copyright on this, given his current practices.

  31. Tony

    @ jonathon

    Sorry, this one wasn't from a web site, but an old history book. The 32 pounder was a very effective weapon and was the main stay of the ship of the line from the late 1700's. I imagine the tests done were from a ship at anchor with spring lines to stabilise it although I can't say for certain.

    However, you are also correct in saying that a lot of fighting was done at much closer range; hence Nelson's comment that "no captain can do very wrong if he lay his ship along side that of the enemy". In many cases they were just blasting away until someone had had enough - and the descriptions of the fighting and the devastation afterwards are truly horrific - it makes some of the modern slash movies look like the teletubbies.

    Note also that the limit of a country's jurisdiction around the coast was established by how far away a ship could sail without being pounded to bits by a shore based battery.

  32. dave

    32 pounder?

    I remember reading about artillery tests conducted at Madras in the early/mid 19th. Accuracy was crap. British ingenuity had solved the problem by the time of the Indian mutiny though:

    "...convicted mutineers were lashed to the muzzles of cannon and had a roundshot fired through their body..."

  33. Eduard Coli

    Difference engine + 800 HP V10?

    Nah, difference engine parts everywhere.

  34. Anonymous Coward
    Thumb Up

    To Quote Jakob Nielsen

    "Building the machine according to the original specifications resulted in a working computer - with one exception: the Difference Engine runs on human power: a person turns a crank. Unfortunately, it's beyond the strength of any person to actually turn that crank, given the many wheels and other parts that it drives. The modern builders had to install a gearing unit to make it possible for a human to supply power to the Difference Engine. (And even so, it was a pretty big guy who ran the machine in the exhibit.)

    I conclude that Babbage's machine, which is often called the world's first computer, had a human factors problem in its original design. Luckily it was easy to fix with some real-world testing - more than 150 years after it was designed."

  35. Mike

    One per desktop (et al)

    The reason it is the size it is: the range in sizes of the various parts meant that for the smallest to be strong enough (great enough cross-section), the largest are, well, the size they are. It is possible that a 1/4-scale model could be built today, using today's materials, today's fabrication processes, and designed with today's clustered supercomputers running FEA software. However, the _point_ of the original exercise was to determine if _Babbage_ could have built it, with the materials and processes available at the time.

    As to "It's a computer, just look at it", well, then EMERAC is a computer :-)

    (NOT! Nor is this)

    As to the "Swede" who built a difference engine, that one lacked many of the error-checking facilities of Babbage's and was as a result a bit "fiddly", IIRC.

    As to crank effort: the current machine has a 4:1 reduction gear. It takes a bit of patience, "feel", or whatever to turn, but I have done so and I am no giant. It would be tiring to turn it at 1:1, and more prone to jams (error-detecting, again), because of the variance in load during the machine cycle, but IMHO, not out of the question. You perhaps underestimate the strength, stamina, and flexibility of the typical Victorian Navvy. :-)

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