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> The Difference Engine was not a computer, because all it did was add and subtract. The definition of computer is pretty grey for the pre-digital era, and it

> The Difference Engine was not a computer, because all it did was add and subtract. The definition of computer is pretty grey for the pre-digital era, and it wasn't turing complete, but is it actually controversial whether it was a computer?

exitb 2y ago
Difference Engine basically implemented one algorithm in hardware, while Analytical Engine was supposed to run a program. I believe that could make the latter one a computer.
- jandrese 2y ago
  The first stored program computer is a remarkable achievement, even if they didn't actually build it.
  - Manuel_D 2y ago
    The analytical engine wasn't a stored program computer. It most closely follows the Harvard architecture, with instructions read from punch card memory. The analytical engine's claim to fame is that it was the first Turing complete computer to be designed.
    - area51org 2y ago
      > with instructions read from punch card memory If that isn't a stored program, I don't know what is.
      - Manuel_D 2y ago
        A stored program computer refers to the computer architecture where program instructions and data are stored in the same memory. This is also referred to as the Von Neumann architecture. In contrast, a lot of early computers were built with separate instruction memory like punch cards. This is called the Harvard Architecture. If the instructions were immutable, which they usually were, then things like modifying the program at runtime were not possible. Concrete examples of this difference is the Harvard Mk 1 and the Manchester Mk 1, the former being a Harvard architecture computer and the latter is a stored program computer or a von Neumann architecture.
        adrian_b 2y ago
        "Babbage architecture" would have been much more accurate than "Harvard architecture", because Howard H. Aiken, the designer of Harvard Mark I, has been explicitly inspired by the work of Babbage into making his automatic computer at Harvard, which was intended as a modern implementation of what Babbage had failed to build. The "Harvard architecture" had nothing to do with Harvard and it was not a novel thing. Having separate memories for programs and for data has been the standard structure for all programmable computers that have been made before the end of WWII, in all countries, and the methods for storing computer programs had been derived from those used in programmable looms and in the much earlier music boxes, which are the earliest programmable sequencers. Like the computer keyboards have a history of millennia since their origin in musical instruments (i.e. organs), the computer program memories have also their origin in (automatic) musical instruments, more than a millennium ago.
- Wowfunhappy 2y ago
  > Difference Engine basically implemented one algorithm in hardware So, did Pong run on a computer?
  - ElevenLathe 2y ago
    No.
  - smitelli 2y ago
    Is my toilet tank a single-algorithm analog computer?
    - deleted 2y ago
      [deleted]
Avicebron 2y ago
Probably not, it's stated in the TFA, the controversy is because Lovelace was a woman and some people think propping her up is basically a DEI retcon in history, the rest of us don't care. But I don't think it's anything whatsoever to do with actual computers
- bazoom42 2y ago
  The parent asks about the Difference Engine. Lovelace wrote about the (more powerful) Analytical Engine. Nobody is denying the Analytical engine was a computer.
- nilamo 2y ago
  That's so funny... Mathematicians for 150 years: Ada Lovelace is kind of on top of it. Random from 2024: probably just a diversity footnote.
  - mrguyorama 2y ago
    Seriously. As the article states, while everyone else was like "Wow cool we will make a machine that makes calculating things easier" Meanwhile Ada over here going "Oh shit this can do literally anything that can be done by steps of math. Someday machines following that formula will make music" Ada is not the first programmer. Ada is the first computer scientist. She understood the ramifications of what we would eventually call "turing complete" systems, and understood the value of "general purpose" in a general purpose computer, and seemingly understood that more than just numbers could be represented and calculated in a computer.
    - grey-area 2y ago
      Yes this is the most interesting thing about her writing - she foresaw a lot of later work.
  - metalman 2y ago
    Funny indeed.Ada Lovelace has been persistantly recognised for a very long time, but has never been held up as a sufferget type mayrter, as by all accounts, she enjoyed herself out on the bleeding edge and is still making people uncomfortable 150 years after not fitting into any stereotypes then. Its clear from the footnotes that, whatever crowd around Babage and Lovelace, grasped the possibilities. Also interesting is that durring the apollo moon mission, the memory modules for the guidance computers were crafted by some of the last lace makers, working by hand, to survive the introduction of the jaquard looms and there punch cards.
SilasX 2y ago
I'm not sure I have a direct answer, but I agree something shouldn't be called a computer if it just does a one-shot, fixed-length calculation before requiring further human intervention. To be a "computer", and be associated with that general conceptspace, it should be Turing-complete and thus capable of running arbitrarily long (up to the limits of memory and hardware rot). Earlier comment expressing annoyance at a mislabeling: https://news.ycombinator.com/item?id=40077408 https://news.ycombinator.com/item?id=40077408
- SilasX 2y ago
  Separate comment to address a subtlety that comes up a lot: Often you'll hear about fully homomorphic encryption (FHE) being Turing-complete. But you can't actually have a Turing complete system with variable-run-time loops that's homomorphically encrypted, because that leaks information about the inputs. When they say FHE is Turing-complete, what they mean is that you can take an arbitrary program requiring Turing completeness, then time-bound it, unroll it into a fixed-length circuit, and run that homomorphically. Since you can keep upping the time bound, you can compute any function. So the system that translates your programs into those circuits, with no limit on the bound you set, could then be called Turing-complete -- but you couldn't say that about any of those circuits individually. Earlier related comment: https://news.ycombinator.com/item?id=40078494 https://news.ycombinator.com/item?id=40078494
jcranmer 2y ago
That the Difference Engine and Analytical Engine belong on the timeline of computing history isn't particularly controversial, but the Difference Engine itself I've never seen anyone try to claim was a computer (it's a mechanical calculator)--the Wikipedia page doesn't even try to link it directly to the history of computers, you have to go to the Analytical Engine to see the Difference Engine's place in the "history of computing" timeline.
- rsynnott 2y ago
  To confuse the issue, though, at one time it was somewhat common to call fixed function calculators like this ‘computers’.
_yb2s 2y ago
I don't think there is anything controversial here- the Difference Engine was a calculator that could only do a predefined set of hardwired computations, the Analytical Engine a true turing complete computer.
retrac 2y ago
Is an early 20th century mechanical desk calculator a computer? There is no consensus on definition but for me, a computer follows a program. Maybe even only one fixed program. But a program. If there is no stepping through a program it is not a computer. Does the iterative method used by the difference engine constitute a program?
- lazide 2y ago
  The term ‘computer’ originates from humans trained (and paid!) to explicitly do lots of math, so it seems to be.

exitb 2y ago

Difference Engine basically implemented one algorithm in hardware, while Analytical Engine was supposed to run a program. I believe that could make the latter one a computer.

jandrese 2y ago
The first stored program computer is a remarkable achievement, even if they didn't actually build it.
- Manuel_D 2y ago
  The analytical engine wasn't a stored program computer. It most closely follows the Harvard architecture, with instructions read from punch card memory. The analytical engine's claim to fame is that it was the first Turing complete computer to be designed.
  - area51org 2y ago
    > with instructions read from punch card memory If that isn't a stored program, I don't know what is.
    - Manuel_D 2y ago
      A stored program computer refers to the computer architecture where program instructions and data are stored in the same memory. This is also referred to as the Von Neumann architecture. In contrast, a lot of early computers were built with separate instruction memory like punch cards. This is called the Harvard Architecture. If the instructions were immutable, which they usually were, then things like modifying the program at runtime were not possible. Concrete examples of this difference is the Harvard Mk 1 and the Manchester Mk 1, the former being a Harvard architecture computer and the latter is a stored program computer or a von Neumann architecture.
      - adrian_b 2y ago
        "Babbage architecture" would have been much more accurate than "Harvard architecture", because Howard H. Aiken, the designer of Harvard Mark I, has been explicitly inspired by the work of Babbage into making his automatic computer at Harvard, which was intended as a modern implementation of what Babbage had failed to build. The "Harvard architecture" had nothing to do with Harvard and it was not a novel thing. Having separate memories for programs and for data has been the standard structure for all programmable computers that have been made before the end of WWII, in all countries, and the methods for storing computer programs had been derived from those used in programmable looms and in the much earlier music boxes, which are the earliest programmable sequencers. Like the computer keyboards have a history of millennia since their origin in musical instruments (i.e. organs), the computer program memories have also their origin in (automatic) musical instruments, more than a millennium ago.
Wowfunhappy 2y ago
> Difference Engine basically implemented one algorithm in hardware So, did Pong run on a computer?
- ElevenLathe 2y ago
  No.
- smitelli 2y ago
  Is my toilet tank a single-algorithm analog computer?
  - deleted 2y ago
    [deleted]

Avicebron 2y ago

Probably not, it's stated in the TFA, the controversy is because Lovelace was a woman and some people think propping her up is basically a DEI retcon in history, the rest of us don't care. But I don't think it's anything whatsoever to do with actual computers

bazoom42 2y ago
The parent asks about the Difference Engine. Lovelace wrote about the (more powerful) Analytical Engine. Nobody is denying the Analytical engine was a computer.
nilamo 2y ago
That's so funny... Mathematicians for 150 years: Ada Lovelace is kind of on top of it. Random from 2024: probably just a diversity footnote.
- mrguyorama 2y ago
  Seriously. As the article states, while everyone else was like "Wow cool we will make a machine that makes calculating things easier" Meanwhile Ada over here going "Oh shit this can do literally anything that can be done by steps of math. Someday machines following that formula will make music" Ada is not the first programmer. Ada is the first computer scientist. She understood the ramifications of what we would eventually call "turing complete" systems, and understood the value of "general purpose" in a general purpose computer, and seemingly understood that more than just numbers could be represented and calculated in a computer.
  - grey-area 2y ago
    Yes this is the most interesting thing about her writing - she foresaw a lot of later work.
- metalman 2y ago
  Funny indeed.Ada Lovelace has been persistantly recognised for a very long time, but has never been held up as a sufferget type mayrter, as by all accounts, she enjoyed herself out on the bleeding edge and is still making people uncomfortable 150 years after not fitting into any stereotypes then. Its clear from the footnotes that, whatever crowd around Babage and Lovelace, grasped the possibilities. Also interesting is that durring the apollo moon mission, the memory modules for the guidance computers were crafted by some of the last lace makers, working by hand, to survive the introduction of the jaquard looms and there punch cards.

SilasX 2y ago

I'm not sure I have a direct answer, but I agree something shouldn't be called a computer if it just does a one-shot, fixed-length calculation before requiring further human intervention. To be a "computer", and be associated with that general conceptspace, it should be Turing-complete and thus capable of running arbitrarily long (up to the limits of memory and hardware rot). Earlier comment expressing annoyance at a mislabeling: https://news.ycombinator.com/item?id=40077408 https://news.ycombinator.com/item?id=40077408

SilasX 2y ago
Separate comment to address a subtlety that comes up a lot: Often you'll hear about fully homomorphic encryption (FHE) being Turing-complete. But you can't actually have a Turing complete system with variable-run-time loops that's homomorphically encrypted, because that leaks information about the inputs. When they say FHE is Turing-complete, what they mean is that you can take an arbitrary program requiring Turing completeness, then time-bound it, unroll it into a fixed-length circuit, and run that homomorphically. Since you can keep upping the time bound, you can compute any function. So the system that translates your programs into those circuits, with no limit on the bound you set, could then be called Turing-complete -- but you couldn't say that about any of those circuits individually. Earlier related comment: https://news.ycombinator.com/item?id=40078494 https://news.ycombinator.com/item?id=40078494

jcranmer 2y ago

That the Difference Engine and Analytical Engine belong on the timeline of computing history isn't particularly controversial, but the Difference Engine itself I've never seen anyone try to claim was a computer (it's a mechanical calculator)--the Wikipedia page doesn't even try to link it directly to the history of computers, you have to go to the Analytical Engine to see the Difference Engine's place in the "history of computing" timeline.

rsynnott 2y ago
To confuse the issue, though, at one time it was somewhat common to call fixed function calculators like this ‘computers’.

_yb2s 2y ago

I don't think there is anything controversial here- the Difference Engine was a calculator that could only do a predefined set of hardwired computations, the Analytical Engine a true turing complete computer.

retrac 2y ago

Is an early 20th century mechanical desk calculator a computer? There is no consensus on definition but for me, a computer follows a program. Maybe even only one fixed program. But a program. If there is no stepping through a program it is not a computer. Does the iterative method used by the difference engine constitute a program?

lazide 2y ago
The term ‘computer’ originates from humans trained (and paid!) to explicitly do lots of math, so it seems to be.