5 ms·

> After all, Babbage's machine could have been built in his time if funding hadn't run out. Funding ran out in large part because of cost overruns due to the f

> After all, Babbage's machine could have been built in his time if funding hadn't run out. Funding ran out in large part because of cost overruns due to the fact that the technology of the time wasn’t capable of building the analytic engine design.

irrational 8y ago
This was my understanding as well. The tight machining tolerances required simply didn't exist in his time.
- ddingus 8y ago
  Given resources, they could potentially have made a machine to machine. The ability was potentially there, but the need perhaps was not. It would have required a generation dedicated to that one task.
- frostburg 8y ago
  It was likely possible with a lot of effort and extensive hand-fitting, just not economically at scale.
randomwalker 8y ago
That's possible, but an alternative explanation for the cost overruns that I've read is that Babbage had terrible project management skills. Wikipedia has this to say: In 1991, the London Science Museum built a complete and working specimen of Babbage's Difference Engine No. 2, a design that incorporated refinements Babbage discovered during the development of the Analytical Engine. This machine was built using materials and engineering tolerances that would have been available to Babbage, quelling the suggestion that Babbage's designs could not have been produced using the manufacturing technology of his time. https://en.wikipedia.org/wiki/Analytical_Engine https://en.wikipedia.org/wiki/Analytical_Engine
- chubot 8y ago
  I just finished reading The Difference Engine yesterday, an entire book about this project, by the project lead! https://www.amazon.com/Difference-Engine-Charles-Babbage-Computer/dp/0142001449 https://www.amazon.com/Difference-Engine-Charles-Babbage-Com... (unfortunately overshadowed in Google Search results by a William Gibson book of the same name) It gives a lot of color on Babbage, but yes the conclusion was that Babbage design basically worked, and could have been built. There were errors in his drawings that they had to correct, but nothing fundamental. The group at the Science Museum spent over 6 years doing this! This is the group that holds most of his papers, drafts, and unfinished machines. Although there are a couple things I want to follow up on. They weren't that specific about what computation they did. And does it still work today? It was extraordinarily finicky. It produced a lot of bit errors, as did mechanical computing devices that came later, which sort of defeated the purpose (it was supposed to calculate tables of logarithms and such with higher accuracy than humans.)
  - azernik 8y ago
    The examples built do indeed keep on working with non-prohibitive maintenance - the 2nd #2-design engine (built in the 2000s for Nathan Myhrvold), was on display at the CHM in Mountain View for 8 years with daily or twice-daily demonstration runs. It sadly went off display in 2016 (probably to go to Myhrvold's private collection) but I saw the demonstration a couple of times and can answer some of your questions: 1. The concrete computation performed was to use the Finite Difference Method (https://en.wikipedia.org/wiki/Finite_difference_method https://en.wikipedia.org/wiki/Finite_difference_method - hence the "Difference Engine" name) to calculate arbitrary polynomials of degree up to IIRC 10. By using Taylor Series, this method could be used to calculate arbitrary functions, like log and sine. This was in fact the same method used to construct logarithmic tables by hand at the time, and had similar nominal precision; the singular goal was to eliminate the bit errors rampant in the old, manual process. 2. The machine removed not just errors in calculation, but also in typesetting; about half the part-count of the original design was in its printer, which could be configured with all kinds of options for typesetting the results. It would output a "print preview" onto paper locally (this was not publicly demonstrated at the CHM because of the enormous mess of ink spills, but the machinery was run dry), and an identical wax mold ready for use in mass printing. This was because many of the bit errors in the existing log/sine/etc. tables were introduced not by the (human) computers, but by the multiple copying steps involved in transforming calculated values into printed pages. 3. Computation was quite reliable - the machine worked in base 10, and mechanisms were carefully designed to freeze up (and be easily resettable to a known-good state, as demonstrations showed) before introducing errors. As far as I know bit errors were unheard of in the demonstration runs. This reliability, like in later electronic computation, was the motivation for using digital rather than analog logic. (Finickiness was mostly limited to those halting conditions - it proved quite sensitive to clock speed (rate of crank turn), but only by the standards of the hand cranking used in demonstrations; connected up to a steam engine with 19th-century rate governors, input power could have been kept clean enough to run with long MTTF.)
kevin_thibedeau 8y ago
Had anyone in the 19th century realized the generality of computing in binary there would have been successful mechanical computers of the age. Doing everything in decimal was part of the problem.
- abecedarius 8y ago
  Charles S. Peirce in the 1880s understood that switching circuits embody Boolean logic, though he never published except in a letter to a student/colleague who was going to work on this but abandoned it. That Babbage and Peirce both had trouble dealing with people may have had a pretty big effect on history.
  - gowld 8y ago
    That's the trick of "autistic" personalities -- better with computers but worse with people. A person better with people but worse with computers wouldn't have succeeded either. Being better at both is rare.
- garmaine 8y ago
  According to the London museum of science, Babbage looked at binary, as well as many other bases and made an informed decision against it. The supremacy of binary is not as obvious with mechanical systems as it is with electrical semiconductors. These machines are built with gears, not switches.
ncmncm 8y ago
Probably if Babbage had employed watchmakers, he could have got it done, but clockwork run on springs isn't as impressive as massive, clanking machinery driven by steam engines. He would still have had the problem of driving typesetting equipment, but that seems like a smaller problem. Output on punched paper tape was the solution the later generation chose, and would have worked. Amusingly, the original telegraph inventions (plural) output dots on paper, but accidents of finance left us with the inferior audio clickery. Sort of like how we are still using x86.
- deleted 8y ago
  [deleted]

irrational 8y ago

This was my understanding as well. The tight machining tolerances required simply didn't exist in his time.

ddingus 8y ago
Given resources, they could potentially have made a machine to machine. The ability was potentially there, but the need perhaps was not. It would have required a generation dedicated to that one task.
frostburg 8y ago
It was likely possible with a lot of effort and extensive hand-fitting, just not economically at scale.

randomwalker 8y ago

That's possible, but an alternative explanation for the cost overruns that I've read is that Babbage had terrible project management skills. Wikipedia has this to say: In 1991, the London Science Museum built a complete and working specimen of Babbage's Difference Engine No. 2, a design that incorporated refinements Babbage discovered during the development of the Analytical Engine. This machine was built using materials and engineering tolerances that would have been available to Babbage, quelling the suggestion that Babbage's designs could not have been produced using the manufacturing technology of his time. https://en.wikipedia.org/wiki/Analytical_Engine https://en.wikipedia.org/wiki/Analytical_Engine

chubot 8y ago
I just finished reading The Difference Engine yesterday, an entire book about this project, by the project lead! https://www.amazon.com/Difference-Engine-Charles-Babbage-Computer/dp/0142001449 https://www.amazon.com/Difference-Engine-Charles-Babbage-Com... (unfortunately overshadowed in Google Search results by a William Gibson book of the same name) It gives a lot of color on Babbage, but yes the conclusion was that Babbage design basically worked, and could have been built. There were errors in his drawings that they had to correct, but nothing fundamental. The group at the Science Museum spent over 6 years doing this! This is the group that holds most of his papers, drafts, and unfinished machines. Although there are a couple things I want to follow up on. They weren't that specific about what computation they did. And does it still work today? It was extraordinarily finicky. It produced a lot of bit errors, as did mechanical computing devices that came later, which sort of defeated the purpose (it was supposed to calculate tables of logarithms and such with higher accuracy than humans.)
- azernik 8y ago
  The examples built do indeed keep on working with non-prohibitive maintenance - the 2nd #2-design engine (built in the 2000s for Nathan Myhrvold), was on display at the CHM in Mountain View for 8 years with daily or twice-daily demonstration runs. It sadly went off display in 2016 (probably to go to Myhrvold's private collection) but I saw the demonstration a couple of times and can answer some of your questions: 1. The concrete computation performed was to use the Finite Difference Method (https://en.wikipedia.org/wiki/Finite_difference_method https://en.wikipedia.org/wiki/Finite_difference_method - hence the "Difference Engine" name) to calculate arbitrary polynomials of degree up to IIRC 10. By using Taylor Series, this method could be used to calculate arbitrary functions, like log and sine. This was in fact the same method used to construct logarithmic tables by hand at the time, and had similar nominal precision; the singular goal was to eliminate the bit errors rampant in the old, manual process. 2. The machine removed not just errors in calculation, but also in typesetting; about half the part-count of the original design was in its printer, which could be configured with all kinds of options for typesetting the results. It would output a "print preview" onto paper locally (this was not publicly demonstrated at the CHM because of the enormous mess of ink spills, but the machinery was run dry), and an identical wax mold ready for use in mass printing. This was because many of the bit errors in the existing log/sine/etc. tables were introduced not by the (human) computers, but by the multiple copying steps involved in transforming calculated values into printed pages. 3. Computation was quite reliable - the machine worked in base 10, and mechanisms were carefully designed to freeze up (and be easily resettable to a known-good state, as demonstrations showed) before introducing errors. As far as I know bit errors were unheard of in the demonstration runs. This reliability, like in later electronic computation, was the motivation for using digital rather than analog logic. (Finickiness was mostly limited to those halting conditions - it proved quite sensitive to clock speed (rate of crank turn), but only by the standards of the hand cranking used in demonstrations; connected up to a steam engine with 19th-century rate governors, input power could have been kept clean enough to run with long MTTF.)

kevin_thibedeau 8y ago

Had anyone in the 19th century realized the generality of computing in binary there would have been successful mechanical computers of the age. Doing everything in decimal was part of the problem.

abecedarius 8y ago
Charles S. Peirce in the 1880s understood that switching circuits embody Boolean logic, though he never published except in a letter to a student/colleague who was going to work on this but abandoned it. That Babbage and Peirce both had trouble dealing with people may have had a pretty big effect on history.
- gowld 8y ago
  That's the trick of "autistic" personalities -- better with computers but worse with people. A person better with people but worse with computers wouldn't have succeeded either. Being better at both is rare.
garmaine 8y ago
According to the London museum of science, Babbage looked at binary, as well as many other bases and made an informed decision against it. The supremacy of binary is not as obvious with mechanical systems as it is with electrical semiconductors. These machines are built with gears, not switches.

ncmncm 8y ago

Probably if Babbage had employed watchmakers, he could have got it done, but clockwork run on springs isn't as impressive as massive, clanking machinery driven by steam engines. He would still have had the problem of driving typesetting equipment, but that seems like a smaller problem. Output on punched paper tape was the solution the later generation chose, and would have worked. Amusingly, the original telegraph inventions (plural) output dots on paper, but accidents of finance left us with the inferior audio clickery. Sort of like how we are still using x86.

deleted 8y ago
[deleted]