What if Babbage..?
Written by Mike James   
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What if Babbage..?
Gears and the Mill
Victorian Programming
The alternative now

It was on this day 220 years ago (December 26 1791) that Charles Babbage was born. The calculating machines he invented in the 19th century, although  never fully  realised in his lifetime, are rightly seen as the forerunners of modern programmable computers. What if he had succeeded? Babbage already had plans for games arcades, chess playing machines, sound generators and desktop publishing. A Victorian computer revolution was entirely possible.




What if the computer had been invented 100 years earlier, in Victorian times?

This isn’t a silly idea.



Charles Babbage
(December 26, 1791- October 18, 1871)


Charles Babbage had conceived of the basic principles of a stored digital computer in 1833 - and no I’m not talking of a glorified calculator. This was the real thing, CPU, memory and programs - and it could have been built.

If you visit the Science Museum in London you can see a working model of Babbage’s “Difference Engine”. It looks like a beautiful work of precision engineering and yet it was built using engineering tolerances that were available at the time. Babbage never built his difference engine, although others did build machines like it during his life time.



Working model of Babbage’s Difference Engine


Although the difference engine attracts most attention it isn’t a computer. It isn’t really even a straightforward calculator. It is specialised machine that will perform a particular type of calculation. One of the reasons Babbage didn’t complete his work on the difference engine is simply that he thought of something much better - the “Analytical Engine”.

So why didn’t he build the analytical engine, was this really a step too far?

One reason was that after people had funded the difference engine to no good result he wasn’t in a good position to raise funds for what looked like an even more risky bet. If he had raised the money then it seems fairly likely that the machine would have worked.

In 1910 his son, Henry P Babbage, built a large hand-operated calculator plus printer based on the CPU of the analytical engine - and it worked.



Working Analytical Engine


Now,170 years after Babbage drafted his original plans for the Analytical Engine, author, journalist and computer scientist  John Graham-Cumming has an embarked on an ambitious, but realistic project to build one for public display. It is called Plan 28, is reference to the extensive documentation which Babbage left  in a mahogany case that Babbage had constructed especially for the purpose.

Graham-Cumming enlisted the help of Doron Swade, who, as curator of computing at the Science Museum in London, masterminded the  building ofd the Difference Engine and as a preliminary step towards Plan 28 the the Science Museum has begun to digitise Babbage's entire archive of plans and notes.

A Design Before Its Time?

But surely even if Babbage had been successful it wouldn’t have changed anything?

Babbage was so far ahead of his time that it would have just been a curiosity not a useful instrument?

Not so.

You would be surprised at just how sophisticated his ideas were. He had invented a notation for designing the calculating mechanisms - something like one of the chip design languages we use today - and he could have gone much further.

More to the point with a working analytical engine other engineers and scientists would have understood what he was getting at. As it was, with only complex plans and his difficult to follow descriptions, very few grasped the fundamental idea of a computer. Imagine what the effect would have been had the idea of a computing engine spread like the idea of a steam engine.






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