💻 The History of Computing

What you’ll learn

1. When 'Computer' Was a Job TitleExplain what 'computer' originally meant, and why the error-prone human tier of table-making created the demand for a machine.Until the twentieth century a computer was a person employed to do arithmetic, and the tables they produced — logarithms, tides, lunar positions — were infrastructure the age depended on. De Prony's application of the division of labour decomposed table-making until the largest tier needed no mathematical training, effectively inventing the program before any machine existed. Because that tier was purely mechanical yet still error-prone, the obvious question arose: why should it be human at all?
2. Babbage, Lovelace, and the Machine That Wasn't BuiltDescribe Babbage's two engines and the architecture of the Analytical Engine, and characterise the Lovelace authorship debate honestly alongside her undisputed insight about generality.Babbage's Difference Engine mechanised table-making by repeated addition but was never completed, though the Science Museum's 1991 build from his drawings proved the design sound. The Analytical Engine went far further — Store, Mill, punched-card instructions, conditional branching and loops — and was a computer in outline, designed in the 1830s. What exactly Lovelace contributed to the Bernoulli program is genuinely disputed among historians, but her observation that the engine manipulates symbols rather than merely numbers is undisputed and is the central idea of computing.
3. The Other Lineage: Holes in CardsTrace the punched-card lineage from Jacquard's loom to Hollerith's census machines, and distinguish instruction-carrying cards from data-carrying cards.Jacquard's 1804 loom attachment put the weaving pattern on punched cards while the loom stayed fixed — separating hardware from instructions a century and a half before the distinction was named, and giving Babbage his input mechanism. Hollerith then used cards to carry data rather than instructions, cutting US census tabulation from years to months and founding the company that became IBM. By 1900 there were two traditions: Babbage's, with the idea and no machine, and Hollerith's, with machines and no general-purpose ambition.
4. Turing's Idea: One Machine for Every TaskExplain the Turing machine and, crucially, the universal machine — the proof that one machine given a description can behave as any other.Turing's 1936 paper answered Hilbert's decision problem in the negative, which first required defining 'mechanical procedure' precisely — so he stripped a human calculator down to a tape, a read/write head, finite states, and a rule table. He then showed that because a rule table is finite it can be written on the tape, so a single universal machine can read a description of any other machine and behave as it does. That description is software, and it is why one device can be a camera, a map and a bank — Lovelace's insight arriving again with a proof attached.
5. War Makes It RealDistinguish the Bombe and Colossus from universal machines, and explain how wartime secrecy distorted the historical record.Bletchley Park mechanised cryptanalytic reasoning at industrial scale, but the Bombe was a fast special-purpose search device for Enigma settings and could do nothing else. Colossus, built by Tommy Flowers and running from December 1943, attacked the Lorenz cipher and was a genuine landmark in large-scale electronic digital computing — yet it too was not universal. Churchill ordered the Colossi destroyed and the programme classified, so Flowers could not describe his own work and credit for firsts went elsewhere, a reminder that the record reflects who was permitted to speak.
6. ENIAC and the People Who Programmed ItExplain ENIAC's paradox — electronic speed with physical reconfiguration — and account for the work and erasure of its six programmers.ENIAC was built to compute artillery firing tables, used roughly 17,468 vacuum tubes and about 30 tons of equipment, and performed some 5,000 additions per second. But its program was its physical wiring, so changing task meant days of replugging cables and setting switches: electronic, yet not universal. Its programmers — McNulty, Jennings, Snyder, Wescoff, Bilas and Lichterman — invented programming practice from wiring diagrams with no manual, and were long unnamed because programming was wrongly assumed to be clerical work.
7. The Stored Program: Software Is BornExplain the stored-program concept and its consequences, situate the von Neumann attribution dispute, and correct the origin myth of the word 'bug'.Putting instructions in memory alongside data turned reprogramming from days of rewiring into seconds of loading numbers, and made programs into objects that programs could manipulate — Turing's universal machine in hardware. The 1945 First Draft carried only von Neumann's name though the ideas came from group work at the Moore School, and its publication destroyed Eckert and Mauchly's patent position. Manchester's Baby ran the first stored program on 21 June 1948; separately, the famous 1947 moth is real but 'bug' was engineering usage since at least Edison in 1878, which is exactly why the log joked 'first actual case'.
8. The Transistor and the ChipExplain why vacuum tubes capped computing, how the transistor and integrated circuit removed that cap, and what the 'tyranny of numbers' was.Tube failure rates scale with quantity, so more computing power meant a machine permanently under repair — the limit was the switch, not the idea. Bardeen and Brattain's transistor at Bell Labs in December 1947 replaced the fragile bottle with solid material, but the next bottleneck was the millions of hand-soldered joints connecting cheap components. Kilby in 1958 and Noyce in 1959 independently made components within a single piece of material so the connections were part of the chip, and by 1971 Intel's 4004 put a whole processor on one flake of silicon.
9. The Computer Becomes PersonalExplain the shift from batch processing to interactive and then personal computing, and why generality found its mass audience.Batch processing existed because the machine cost more than the user's time, so programmers queued with card decks for hours-later printouts. Time-sharing made computing interactive and DEC's minicomputers — the PDP-8 at around $18,000, then the influential PDP-11 — made a machine something a department could own and walk up to. The microprocessor then collapsed the cost barrier: the Altair 8800 in 1975, the Apple I in 1976, and VisiCalc in 1979, which gave businesses a reason to buy a computer for a task nobody had designed it for.
10. The Machine Becomes a MediumExplain packet switching and the web's open release, and draw the course's argument together: every era is the same idea of generality getting closer to hardware that can hold it.ARPANET's packet switching gave the network no centre and kept intelligence at the edges, so nobody needed permission to build something new on it — the first message, on 29 October 1969, crashed after 'LO'. Berners-Lee combined the URL, HTTP and HTML at CERN in 1989, and CERN's 1993 decision to release the web royalty-free is why it beat the systems that charged. The through-line closes here: Babbage had the design without the workshops, Turing the proof without hardware, ENIAC the speed without universality — and a modern phone is simply the universal machine being handed different descriptions.

Questions this course answers

Grounded in trusted sources

• Ceruzzi, P. E., A History of Modern Computing (2nd ed., MIT Press, 2003)
• Swade, D., The Difference Engine: Charles Babbage and the Quest to Build the First Computer (Viking, 2001)
• Turing, A. M., 'On Computable Numbers, with an Application to the Entscheidungsproblem', Proceedings of the London Mathematical Society, 1936
• Hodges, A., Alan Turing: The Enigma (Burnett Books, 1983)
• Copeland, B. J. (ed.), Colossus: The Secrets of Bletchley Park's Codebreaking Computers (Oxford University Press, 2006)
• Haigh, T., Priestley, M. & Rope, C., ENIAC in Action: Making and Remaking the Modern Computer (MIT Press, 2016)
• Kleiman, K., Proving Ground: The Untold Story of the Six Women Who Programmed the World's First Modern Computer (Grand Central, 2022)
• Riordan, M. & Hoddeson, L., Crystal Fire: The Birth of the Information Age (W. W. Norton, 1997)

Every Wunder lesson is built from real, reputable sources — never invented.

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