Skip to main content

First opinion on whether the Analytical Engine could be built

I asked John Walker who maintains a lovely web site of information about the Analytical Engine whether he knew of any serious attempt to build it. He was kind enough to reply.

To my knowledge, nobody has made a serious attempt to build the Analytical Engine or even a seriously scaled down version of it. I think the general consensus (which, in part, informed the various British commissions which decided not to fund the project) is that it is unlikely in the extreme that a machine which would be necessarily so large would not fall victim to "tolerance creep", where tolerances in individual components would eventually add to make large scale interfaces (for example, between the Mill and the Store) unreliable.

Babbage was aware of this problem and addressed it in his papers. His solution was to design the machinery so that it would jam in case of error, but then the question is, how often would it jam? If it jammed every second and a typical computation took several hours, a room full of people with log tables could out-compute the Analytical Engine.

I'd think it would be beyond crazy to try to raise the funds to construct the complete Analytical Engine. After the Singularity, when we're all 10^16 times as wealthy as at present and can build diamonoid machinery with atomic precision, I'd say go for it, but then tens of thousands of people will have done so within the first 24 hours after the Transition.

Gen. Henry P. Babbage's description of an attempt to build just a component of the Engine:

is instructive of the problems of mechanical tolerances. We can build things much more precisely than in his day (although much of the progress in our technology has been in coping with sloppiness, not improving precision), but ultimately large scale computation depends upon robust digital storage which is immune to noise:

Any macroscopic mechanical system has at best a modest level of noise immunity, and when you imagine a machine the size of an auditorium with hundreds of thousands of parts, the challenge seems overwhelming.

I'm a balding engineer, and I've seen many great ideas founder on the rocky shore of reality. I think the British were *right* not to fund the Analytical Engine; it was a superb idea a century before its time.

So go prove me wrong.

(And ask yourself, as I often do, "What are the superb ideas we have today which are a century before their time?")

I shall continue to investigate. If you care about this topic you can follow the label babbage. If you have an informed technical opinion on this please contact me.


Popular posts from this blog

How to write a successful blog post

First, a quick clarification of 'successful'. In this instance, I mean a blog post that receives a large number of page views. For my, little blog the most successful post ever got almost 57,000 page views. Not a lot by some other standards, but I was pretty happy about it. Looking at the top 10 blog posts (by page views) on my site, I've tried to distill some wisdom about what made them successful. Your blog posting mileage may vary. 1. Avoid using the passive voice The Microsoft Word grammar checker has probably been telling you this for years, but the passive voice excludes the people involved in your blog post. And that includes you, the author, and the reader. By using personal pronouns like I, you and we, you will include the reader in your blog post. When I first started this blog I avoid using "I" because I thought I was being narcissistic. But we all like to read about other people, people help anchor a story in reality. Without people your bl

Your last name contains invalid characters

My last name is "Graham-Cumming". But here's a typical form response when I enter it: Does the web site have any idea how rude it is to claim that my last name contains invalid characters? Clearly not. What they actually meant is: our web site will not accept that hyphen in your last name. But do they say that? No, of course not. They decide to shove in my face the claim that there's something wrong with my name. There's nothing wrong with my name, just as there's nothing wrong with someone whose first name is Jean-Marie, or someone whose last name is O'Reilly. What is wrong is that way this is being handled. If the system can't cope with non-letters and spaces it needs to say that. How about the following error message: Our system is unable to process last names that contain non-letters, please replace them with spaces. Don't blame me for having a last name that your system doesn't like, whose fault is that? Saying "Your

The Elevator Button Problem

User interface design is hard. It's hard because people perceive apparently simple things very differently. For example, take a look at this interface to an elevator: From flickr Now imagine the following situation. You are on the third floor of this building and you wish to go to the tenth. The elevator is on the fifth floor and there's an indicator that tells you where it is. Which button do you press? Most people probably say: "press up" since they want to go up. Not long ago I watched someone do the opposite and questioned them about their behavior. They said: "well the elevator is on the fifth floor and I am on the third, so I want it to come down to me". Much can be learnt about the design of user interfaces by considering this, apparently, simple interface. If you think about the elevator button problem you'll find that something so simple has hidden depths. How do people learn about elevator calling? What's the right amount of