Eniac, the First General-Purpose Digital Computer, Turns 80(spectrum.ieee.org) |
Eniac, the First General-Purpose Digital Computer, Turns 80(spectrum.ieee.org) |
Though the article is very US focussed, keeping quiet that German engineer Konrad Zuse completed the Z3 in May 1941, five years before ENIAC, effectively creating the world's first working programmable and fully automatic digital computer. While ENIAC required days of manual cable patching to program, the Z3 was quickly programmed by a punched tape ("Lochstreifen"), and Zuse also has invented Plankalkül between 1942 and 1945, which is widely recognized as the world's first high-level programming language. The cooperation between Zuse and ETH Zurich eventually led to the first self-compiling compiler and eventually Algol 60 (see "The European Side of the Last Phase of the Development of ALGOL 60" by Peter Naur in ACM SIGPLAN "History of Programming Languages" from 1978). And there was also the British Colossus, which was also a "programmable computer" and successfully utilized vacuum tubes for code-breaking by early 1944.
ENIAC is notable because it was the first intentionally general purpose computer to be built.
[0] https://www.inf.fu-berlin.de/inst/ag-ki/rojas_home/documents...
ENIAC was built for a special purpose, the computation of artillery tables.
It was a bespoke computer built for a single customer: the United States Army's Ballistic Research Laboratory.
This is why it has been designed as the digital electronic equivalent of the analog mechanical computers that were previously used by the Army and why it does not resemble at all what is now meant by "general-purpose computer".
The computers of Aiken and Zuse were really intentionally general-purpose, their designers did not have in mind any specific computation, which is why they were controlled by a program memory, not by a wiring diagram.
What you claim about Z3 being general purpose by accident does not refer to the intention of its designer, but only to the fact that its instruction set was actually powerful enough by accident, because at that early time it was not understood which kinds of instructions are necessary for completeness.
All the claims made now about ENIAC being general-purpose are retroactive. Only after the war ended and the concept of a digital computer became well understood, the ENIAC was repurposed to also do other tasks than originally planned.
The first truly general-purpose electronic digital computers that were intentionally designed to be so were those designed based on the von Neumann report.
Before the completion of the first of those, there were general-purpose hybrid electronic-electromechanical digital computers, IBM SSEC being the most important of them, which solved a lot of scientific and technical problems, before electronic computers became available.
That's a pretty academic take. Neither Eckert, nor Mauchly, nor Zuse knew about Alan Turing’s 1936 paper when they designed their machines. The classification of ENIAC (and the Z3) as a "universal Turing machine" is entirely a retroactive reinterpretation by later computer scientists. John von Neumann knew the paper and was aware of its significance, but he only turned up in the ENIAC project when the design was complete. At this time, Eckert and Mauchly were already well aware of ENIAC's biggest flaw (the massive effort to reprogram the machine, and in fact they came up with the stored-program concept which von Neumann later formalized). ENIAC’s funding and primary justification were for the very specific purpose of calculating artillery firing tables for the military. The machine was built for this purpose, which included the feature which retroactively led to the mentioned classification.
The most obvious of the problems is that a computer isn't a singular technology that springs up de novo, but something that develops from antecedents over a long, messy transition problem that requires a judgement call as to when the proto-computer becomes an actual computer. A judgement call which is obviously going to be biased based on the other considerations. Consider, for a more contemporary example, what you would argue as the "first smartphone" or the "first LLM." Personally, I think the ENIAC is still somewhat too proto-computer for my tastes: I'd prefer a "first" that uses binary arithmetic and has stored programs, neither of which is true for the ENIAC.
The second major issue is it's also instructive to look at the candidates' influence on later development. Among the contenders for "first computer," it's unfortunately kinda clear that ENIAC has the most lasting influence. ENIAC's development produced the papers that directly inspires the next generation of machines. Colossus is screwed here because of the secrecy of the code-breaking effort. Meanwhile, Zuse and Z3 suffer from being on the losing end of WW2. ABC has a claim here, but it's not clear whether or not the developers of ENIAC drew influence from ABC or not.
The final major issue isn't so much an issue by itself but rather something that colors the interpretation of the first two issues: national pride. An American is far more likely to weight the influence and ingenuity of the ENIAC and similar machines to label one of them the "first computer." A UK person would instead prefer to crown Colossus or the Manchester Baby. A German would prefer the Z3.
If this is correct, it was not a von Neuman machine originally, but it eventually became one, and at approximately the same time as the Manchester Baby.
The problem is that anything that gets into Wikipedia becomes ingrained in the Internet's collective mind, which then can't be changed.
What the article says is different: "the first large-scale, general-purpose, programmable electronic digital computer".
The claim of the article can be considered correct, and "electronic" is a part that cannot be deleted from it without falsifying the claim.
Before ENIAC, there have been digital computers that were much more general-purpose, because they run programs written on punched tape, instead of requiring a rewiring like ENIAC.
ENIAC, which evolved from the analog computers known as differential analyzers, had a structure closer to an FPGA than to a modern digital computer.
In contrast, an earlier relay computer like Harvard Mark I was intended as a successor of the mechanical digital computer designed by Charles Babbage, so it already had the same structure with a modern digital computer, except that it used different kind of memories for data and for programs, hence the name "Harvard architecture". The same was true for the Zuse computer.
The earlier ABC digital computer was electronic, but it can be considered as special-purpose, not general-purpose. The first relay computers at Bell Labs may also be considered as special purpose.
https://www.cs.drexel.edu/~bls96/eniac/simulator.html
And a programming manual:
https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=846...
It's really got a nice archaic character.
They had to program it by physically rewiring patch cables and flipping switches. There was no programming language, no stored program. The "software" was the hardware configuration itself.
It took another decade before FORTRAN (1957) gave programmers a way to write instructions in something resembling human language.
The transition period where patch cables and stored programs coexisted is one of the most interesting eras in computing history.
The tube circuit resembled the ones shown in the photo linked below (although none of those in the photo are from ENIAC).
https://en.wikipedia.org/wiki/File:Women_holding_parts_of_th...
Surprisingly light though...
Perhaps AI aided?
Vacuum tubes break too often. Once per year? But if you have a thousand of them you have to change one very often. So I guess they have a lot of space for humans repairing it.
https://mitpress.mit.edu/9780262334433/eniac-in-action/
An interesting revelation here is that, although ENIAC was not originally conceived as a stored program computer, it was quite early converted to one. They repurposed a lookup table intended to calculate functions to store instructions instead. Many of the well-known ENIAC calculations, such as Monte Carlo simulations, were programmed in this mode.
That is, they were not trying to follow the notion of a universal computing device that had already been defined by Turing and Church at the time. They were just trying to build something like a huge programmable calculator, but they ended up building a universal computation device anyway.
The Harvard Mark 1 ran its first program in 1944, but didn’t have branches as we understand them until 1946:
https://en.wikipedia.org/wiki/Harvard_Mark_I
Apparently, you could achieve loops by taping the input program into a physical loop, even in 1944.
> Mauchly's teaching career truly began in 1933 at Ursinus College where he was appointed head of the physics department, where he was, in fact, the only staff member.
It was a balloon?
next 20 years ;)
The earlier relay computers were Turing complete.
For ENIAC it also does not make sense to claim that it was Turing complete. Such a claim can be made for a computer controlled by a program memory, where you have a defined instruction set, and the instruction set may be complete or not. If you may rewire arbitrarily the execution units, any computer is Turing complete.
The earlier ABC electronic computer was built for a special purpose, the solution of systems of linear algebraic equations, like ENIAC was built only for a special purpose, the computation of artillery tables.
By rewiring the ABC electronic computer you could have also computed anything, so you can say that it was Turing complete, if rewiring is allowed.
The only difference is that rewiring was simpler in ENIAC, because it had been planned to be easy, so there were special panels where you could alter the connections.
Neither ABC nor ENIAC had enough memory to be truly general-purpose, and by the end of the war it was recognized that this was the main limitation for extending the domain of applications, so the ENIAC team proposed ultrasonic delay lines as the solution for a big memory (inspired by the use of delay lines as an analog memory in radars), while von Neumann proposed the use of a cathode ray tube of the kind used in video cameras (iconoscope; this was implemented first in the Manchester computers).
Because ENIAC was not really designed as general-purpose, its designers originally did not think about high-capacity memories. On the other hand, John Vincent Atanasoff, the main designer of the ABC computer, has written a very insightful document about the requirements for memories in digital computers, years before ENIAC, where he analyzed all the known possibilities and where he invented the concept of DRAM, but implemented with discrete capacitors. Later, the proposal of von Neumann was also to use a DRAM, but to use a cheaper and more compact iconoscope CRT, instead of discrete capacitors.
While the ABC computer was not general-purpose as built, the document written by Atanasoff in 1940, “Computing Machine for the Solution of Large Systems of Linear Algebraic Equations”, demonstrated a much better understanding of the concept of a general-purpose electronic digital computer than the designers of ENIAC would demonstrate before the end of 1944 / beginning of 1945, when they realized that a bigger memory is needed to make a computer suitable for any other applications, i.e. for really making it "general purpose".
Soon after that publication, many teams in many places and in several countries have started designing computers and a lot of research results have been published by them, which has lead to the establishment of the computer industry.
The first computer company was a flop, they got lucky that they were bought eventually, otherwise they would not have been able to deliver a useful product. UNIVAC was indeed the first important commercial computer (not the first commercial computer). Nevertheless, UNIVAC was mostly already obsolete at the time of its introduction, due to the use of the delay line memories, for which better alternatives were known. UNIVAC did have a technical first nonetheless, it was the first to use magnetic tapes. However soon the competition (i.e. IBM) made more reliable and also cheaper magnetic tape units.
In USA, UNIVAC had the advantage of being the first on the market, but the IBM computers that followed shortly were more innovative, so IBM deserved becoming the leader of the market instead of UNIVAC. Moreover, IBM was more open at that time and they published a lot of useful technical information about their computers, which contributed to the advancement of the entire computing industry.
The ENIAC team and their successors had a quite minor contribution to the early years of the US computing industry, in comparison with research centers like IAS, universities like MIT, government agencies like NBS (the predecessor of NIST) or companies like IBM, ATT and a few others, all of which introduced essential innovations in computers and they also published the results of their work, enabling the reuse by others.
The report was not published formally, but it was "leaked", so it does not have any credits for the ideas contained in it.
Because of this, with few exceptions it is impossible to determine with certainty which parts of the report are original ideas of von Neumann and which parts are ideas that von Neumann might have learned during the discussions with the ENIAC team.
An example of an idea that certainly did not come from the ENIAC team was the proposal to use an iconoscope CRT as the main memory (which was implemented first in the British Manchester computers, so such a memory became known as a Williams-Kilburn tube). The ENIAC team had a different idea of what to use as a memory, i.e. delay lines taken from radars. Von Neumann replaced this suggestion with a CRT, because he thought that a random-access memory is better.
The von Neumann report had an exceptional importance because it defined with perfect clarity what a digital computer should be, which should be its structure and then provided a detailed description of how such a computer should be designed, which was good enough to enable anyone who read the report to build such a computer. This effect really happened, and a great number of teams at universities, government agencies, independent research centers like IAS and various companies, both in USA and in other countries, have built electronic computers in the following decade, exploring various design options.
There is no doubt that the clarity of the report is due to von Neumann and whichever were the ideas of the ENIAC team about a future computer, they were much more jumbled.
Because the ENIAC team did not publish their ideas (and they did not intend to, because they already wanted to monetize what they had learned about computers, by founding a private company), it does not really matter what they thought. The world has learned how to make general-purpose electronic computers from the von Neumann report.
ENIAC was a programmable computing automaton, but it was not a digital computer in the modern sense of the word, i.e. a digital system with 4 levels of closed positive-feedback loops (the complexity of a digital system is determined by the number of levels of nested positive-feedback loops, combinational logic has 0 levels, a memory has 1 level, an automaton has 2 levels, a processor has 3 levels and a computer has 4 levels; these are minimum numbers, as a real device may have more levels than strictly necessary, to achieve various advantages).
Programming the IBM ASCC (a.k.a. Harvard Mark I) was much closer to the programming a modern computer in comparison with ENIAC, as it had an instruction set and programmers wrote a sequence of instructions on punched tapes. However even ASCC had some panels where it was possible to rewire some of the execution units to change their behavior, i.e. to change what some of the instructions from the instruction set did, but that was not the primary means for programming the computer. In ASCC the rewiring was akin to the microprogramming available in some later electronic computers, where you could change what some instructions did or you could add custom instructions.
Among the programmers of the IBM ASCC, Grace Hopper became later famous due to her contributions to the first high-level programming languages.
Therefore the profession of programmer has not started with ENIAC, even if the ENIAC programmers were among the first programmers.
The hardware was the prestigious work, the programming was considered clerical.
That framing took decades to reverse.
As for the objection that it wasn’t stored program, I was interested to learn that it was converted to stored program operation after only two years or so of operation, using the constant table switches as the program store. But the Manchester Baby, which used the same memory for code and data was more significant in the history of stored program machines.
On the general question of “first computer”, I think the answer is whatever machine you want it to be if you heap enough conditional adjectives on it.
True. Mauchly was a physics professor interested in meterology, and he knew that predicting the weather and calculating an artillery shell's flight are mathematically the same type of problem, which was important to get funding. In the fifties, Eniac was even used to calculate weather forecasts (see https://ams.confex.com/ams/2020Annual/webprogram/Manuscript/...). So these were just two related special problems, and it would be a stretch to interpret this as an intention to build a general-purpose computer. The latter had to wait until the sixties.
It seems like you’re not trying particularly hard to avoid the idea of “monetizing” the computer to sound pejorative. It was the creation of the computer _industry_ that transformed the world and established the import of computers, was it not? You were never getting there without monetization. What good is the spread of ideas if someone, somewhere doesn’t eventually start selling computers? This grates especially hard given that the academics were the ones who acted unscrupulously by lifting their ideas and publicizing them without permission or credit. (“Leaked” is a charitable way to say “deliberately disseminated without caution”).
I agree the stored program is important, but the stored program is of ENIAC vintage, even if it wasn’t implemented on it. And Eckert and Mauchly definitively came to this idea before the involvement of Von Neumann. The thing is, they had an obligation to finish the machine they had promised to build for the army before pursuing such a major redesign. So all they COULD do was informally collect their ideas for a 2.0. Von Neumann arrives, absorbs what they’re up to, synthesizes it (including ‘the big idea’ that ENIAC was missing), and the rest is history. That synthesis is published without their names, and that is why we talk about the Von Neumann architecture. Look, I’m sure it’s true that the crispness of that paper can be attributed to Von Neumann, but it’s a non-sequitur to assume that Eckert and Mauchly’s ideas were jumbled. They were at least organized enough to be building a working machine in the background, and if we’re going to argue that the important thing was promulgation of enough information for others to replicate, than the practicum is more important than mathematical tidiness.
In fact, if we’re talking about how the ideas spread, the paper is frankly overblown. The Moore school lectures were really what caused the Cambrian explosion of electronic computing. There, you can find Eckert and Mauchly utterly central to the elucidation of how to build a general purpose electronic computer. And hey look, there they are, deliberately sharing the ideas out to interested practitioners, in a more pragmatic and direct way than the paper.
What I’m building to here is that E&M starting a company was not evidence that they were just out to make a buck. On the contrary, what it shows is that they had _foresight_ about what the next interesting chapter was bound to be. With the Moore School Lecrures, the ‘publishing of the ideas’ stage was over - the next step was to begin building more machines that could do more computation for more users. And while there was plenty that happened afterward to refine the theoretical model, they were absolutely correct that that’s where the action was. In fact, I think that if you look at what many of these proposed fathers of computing did next, it’s an excellent litmus test of how central they actually were. Some of the sillier ones like Atanasoff just forget about their supposed invention and go on with life - that’s a tell that they weren’t that interested in general-purpose, high speed computing. Whereas E&M’s follow-on work was to advance the field even in the face of great setback. This also completely deconstructs the idea that they were just thinking about artillery, or just thinking about weather. They were thinking about _computing_, and their careers afterwards demonstrate this.
While ENIAC, being completely electronic, remained faster than SSEC for a few problems, most problems could not be solved at all on ENIAC, because it had no big-capacity memory, so for most computing problems SSEC was the best choice until the completion of the first electronic computers with memories based either on cathode-ray tubes or on delay lines or on magnetic drums.
IBM SSEC was available as a public computing service, so it was used by many companies and institutions. Besides SSEC, before the first electronic computers there were a few others electromechanical computers, e.g. at Bell Labs or at Harvard, but those were slower and had fewer users.
She had to fight to convince people that programs could be written in English-like words, her colleagues thought the idea was absurd because "computers don't understand English."
I kind of think she was at White Sands at the time, so... maybe look at what White Sands was using for missile trajectory calculations around 1954 or 1955?
