[squeak-dev] The Old Man

Andres Valloud AVALLOUD at roadrunner.com
Mon Mar 31 03:31:45 UTC 2008


I can't help the feeling that this is derogatory of the work of Babbage 
on the grounds that he never completed anything.  I thought that without 
knowing the specifics, it's easy to dismiss the fact that Babbage was 
trying to do what had not been achieved before.  Moreover, I think it is 
just as easy to miss the fact that we enjoy about 150 years of 
efficiencies gained in our work processes that were not available at his 

I suspected there was something wrong here, particularly from what I had 
studied about history of mathematics, so I did a little research.  From 
Wikipedia, we find out the following...

"*Charles Babbage* FRS <http://en.wikipedia.org/wiki/Royal_Society> (26 
December <http://en.wikipedia.org/wiki/December_26> 1791 
<http://en.wikipedia.org/wiki/1791> London 
<http://en.wikipedia.org/wiki/London>, England 
<http://en.wikipedia.org/wiki/England> – 18 October 
<http://en.wikipedia.org/wiki/October_18> 1871 
<http://en.wikipedia.org/wiki/1871> Marylebone 
<http://en.wikipedia.org/wiki/Marylebone>, London 
<http://en.wikipedia.org/wiki/London>, England 
<http://en.wikipedia.org/wiki/England> ^[1] 
<http://en.wikipedia.org/wiki/Charles_Babbage#cite_note-0> ) was an 
English <http://en.wikipedia.org/wiki/England> mathematician 
<http://en.wikipedia.org/wiki/Mathematician>, philosopher 
<http://en.wikipedia.org/wiki/Philosopher>, and mechanical engineer 
<http://en.wikipedia.org/wiki/Mechanical_engineer> who originated the 
idea of a programmable computer <http://en.wikipedia.org/wiki/Computer>. 
Parts of his uncompleted mechanisms are on display in the London Science 
Museum <http://en.wikipedia.org/wiki/London_Science_Museum>. In 1991 a 
perfectly functioning difference engine 
<http://en.wikipedia.org/wiki/Difference_engine> was constructed from 
Babbage's original plans. Built to tolerances achievable in the 19th 
century, the success of the finished engine indicated that Babbage's 
machine would have worked. Nine years later, the Science Museum 
completed the printer <http://en.wikipedia.org/wiki/Computer_printer> 
Babbage had designed for the difference engine, an astonishingly complex 
device for the 19th century. Babbage is credited with inventing the 
first mechanical computer that eventually led to more complex designs."

In particular,

"In 1991 a perfectly functioning difference engine 
<http://en.wikipedia.org/wiki/Difference_engine> was constructed from 
Babbage's original plans. Built to tolerances achievable in the 19th 
century, the success of the finished engine indicated that Babbage's 
machine would have worked."


But it gets better.  Furthermore,

"Soon after the attempt at making the difference engine crumbled, 
Babbage started designing a different, more complex machine called the 
Analytical Engine <http://en.wikipedia.org/wiki/Analytical_Engine>. The 
engine is not a single physical machine but a succession of designs that 
he tinkered with until his death in 1871. The main difference between 
the two engines is that the Analytical Engine could be programmed using 
punch cards <http://en.wikipedia.org/wiki/Punch_cards>, an idea unheard 
of in his time. He realized that programs could be put on similar cards 
so the person had to only create the program initially, and then put the 
cards in the machine and let it run. The analytical engine was also 
proposed to use loops of Jacquard 
<http://en.wikipedia.org/wiki/Jacquard_loom>'s punched cards to control 
a mechanical calculator, which could formulate results based on the 
results of preceding computations. This machine was also intended to 
employ several features subsequently used in modern computers, including 
sequential control, branching, and looping, and would have been the 
first mechanical device to be Turing-complete 

 From this, it would appear to be that Lord Moulton missed the point.  I 
wouldn't blame him for that.


PS: either the 1870 or 1880 US census was the first one done with the 
assistance of punched cards.  IIRC, it was the 1880 one.

Marcus Denker wrote:
> "One of the sad memories of my life is a visit to the celebrated 
> mathematician and inventor, Mr Babbage. He was far advanced in age, 
> but his mind was still as vigorous as ever. He took me through his 
> work-rooms. In the first room I saw parts of the original Calculating 
> Machine, which had been shown in an incomplete state many years before 
> and had even been put to some use. I asked him about its present form. 
> 'I have not finished it because in working at it I came on the idea of 
> my Analytical Machine, which would do all that it was capable of doing 
> and much more. Indeed, the idea was so much simpler that it would have 
> taken more work to complete the Calculating Machine than to design and 
> construct the other in its entirety, so I turned my attention to the 
> Analytical Machine.'"
> "After a few minutes' talk, we went into the next work-room, where he 
> showed and explained to me the working of the elements of the 
> Analytical Machine. I asked if I could see it. 'I have never completed 
> it,' he said, 'because I hit upon an idea of doing the same thing by a 
> different and far more effective method, and this rendered it useless 
> to proceed on the old lines.' Then we went into the third room. There 
> lay scattered bits of mechanism, but I saw no trace of any working 
> machine. Very cautiously I approached the subject, and received the 
> dreaded answer, 'It is not constructed yet, but I am working on it, 
> and it will take less time to construct it altogether than it would 
> have token to complete the Analytical Machine from the stage in which 
> I left it.' I took leave of the old man with a heavy heart."
> --    Lord Moulton
> -- 
> Marcus Denker  --  denker at iam.unibe.ch
> http://www.iam.unibe.ch/~denker

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